METHODS AND SYSTEMS FOR PRODUCING SOLID INORGANIC CARBONATE AND BICARBONATE COMPOUNDS

Abstract

The present disclosure includes a method of producing solid inorganic carbonate compounds by capturing, converting, and storing carbon dioxide comprising providing one or more precursor compound; providing one or more carbon dioxide capture solvent or capture additive; and reacting said one or more precursor compound with said one or more carbon dioxide capture solvent or capture additive under conditions effective to produce one or more solid inorganic carbonate compound. Also disclosed is a method of producing solid inorganic bicarbonate compounds by capturing, converting, and storing carbon dioxide comprising providing one or more precursor compound; providing one or more carbon dioxide capture solvent or capture additive; and reacting said one or more precursor compound with said one or more carbon dioxide capture solvent or capture additive under conditions effective to produce one or more solid inorganic bicarbonate compound. Also disclosed herein are systems for producing solid inorganic carbonate and bicarbonate compounds.

Claims

1-166. (canceled)

167. A method of producing one or more solid inorganic carbonate compound or inorganic bicarbonate compound by capturing, converting, and storing carbon dioxide, said method comprising: providing one or more precursor compound; providing one or more carbon dioxide capture solvent or capture additive; and reacting said one or more precursor compound with said one or more carbon dioxide capture solvent or capture additive under conditions effective to produce one or more solid inorganic carbonate compound.

168. The method of claim 167, wherein the one or more precursor compound is a non-carbonate metal species or a non-bicarbonate metal species.

169. The method of claim 167, wherein the one or more precursor compound is a solid precursor compound or a liquid precursor compound.

170. The method of claim 167, wherein the one or more precursor compound is selected from the group consisting of a silicate compound, an oxide compound, a chloride compound, a hydroxide compound, a nitrate compound, a nitrite compound, a sulfite compound, and a sulfate compound.

171. The method of claim 167, wherein the one or more precursor compound is a calcium-, magnesium-, lithium-, or aluminum-bearing silicate or a calcium-, magnesium-, lithium-, or aluminum-bearing oxide.

172. The method of claim 170, wherein the one or more precursor compound is selected from the group consisting of CaO, CaSiO3, MgO, LiCl, MgCl2, CaCl.sub.2, NaCl, heterogeneous mineral and rock matrices, and combinations thereof.

173. The method of claim 167, wherein the one or more precursor compound comprises fly ash, steel slag, minerals, mine-tailings, industrial residues, or rocks.

174. The method of claim 167, wherein the one or more carbon dioxide capture solvent or capture additive comprises an amine, an amino acid, an amino acid salt, an amine functional group, for carbon dioxide capture, or a carboxyl functional group for carbon dioxide capture.

175. The method of claim 174, wherein, when the one or more carbon dioxide capture solvent or capture additive comprises an amine, the amine is selected from the group consisting of monoethanolamine, piperazine, diethanolamine, 2-amino-2-methyl-1-propanol, and methyldiethanolamine.

176. The method of claim 174, wherein, when the one or more carbon dioxide capture solvent or capture additive comprises Monoethanolamine, Diethanolamine, Monoethanoldiamine, 2-Amino-2-methyl-1-propanol, methyldiethanolamine, Imidazole, 1-Methylimidazole, 2-Methylimidazole, 4(5)-Methylimidazole, 2-Ethylimidazole, 1,2-Dimethylimidazole, 2-Ethyl 4-methylimidazole, Triethylenediamine (TEDA), 3-Quinuclidinol (3-QD), 4-Hydroxy-1-methylpiperidine (HMPD), 1-(2-Hydroxyethyl) piperidine (HEPD), 4-(2-Hydroxyethyl) morpholine (HEMor), Tropine, Dimethylaminoethoxyethanol (DMAEE), 2-(Diethylamino) ethanol (DEEA), 3-(Aminomethyl), piperidine (3AM-PD), N-methyl-diethanolamine (MDEA), 2-Amino-2-methyl-1-propanol (AMP), 1,3-Diaminopentane (1,3-DAP), 2-(Aminomethyl) piperidine (2AM-PD), 4-Aminopiperidine (4A-PD), Diisopropanolamine (DIPA), 2-Amino-1-butanol (2-AB), 2-Amino-2-ethyl-1,3-propanediol (AEPD), 2-(Isopropylamino) ethanol (IPAE), N,N-Dimethylglycine (DMG), L-Proline (L-Pro), L-Proline (L-Pro), 4-Hydroxy-L-proline (HL-Pro), Benzylamine, N-benzylethanolamine, 4-(Aminomethyl) piperidine (4AM-PD), 2,2,6,6-tetramethyl-piperidin-4-one, 4-(3-Aminopropyl) morpholine (APMor), 1-(2-Hydroxyethyl) piperazine (HEP), 1,2-Bis(2-aminoethoxy) ethane (BAEE), Bis[2-(N,N-dimethylamino) ethyl] ether (BDMAEE), 3-(Dimethylamino)-1,2-propanediol (DMA-PDL), 3-(Diethylamino)-1,2-propanediol (DEA-PDL), 2-(Diisopropylamino) ethanol (DIPAE), 3-Methoxypropylamine (MOPA), 2-(2-dimethylaminoethoxy)-ethanol, 3-dimethyl-amino-propan-1-ol, Pyridine, N,N,N,N-tetramethylethylenediamine (TMEDA), or any combinations thereof.

177. The method of claim 174, wherein, when the one or more carbon dioxide capture solvent or capture additive comprises an amino acid or amino acid salt.

178. The method of claim 177, wherein the glycine compound is glycinate.

179. The method of claim 167, wherein the one or more solid inorganic carbonate compound is selected from the group consisting of magnesite, hydrated magnesium carbonates, calcite, vaterite, aragonite, calcium carbonate (CaCO3), magnesium carbonate (MgCO3), and lithium carbonate (LiCO.sub.3), sodium carbonate (Na.sub.2CO.sub.3), potassium carbonate (K.sub.2CO.sub.3), caesium carbonate (Cs.sub.2CO.sub.3), ammonium bicarbonate ((NH.sub.4).sub.2HCO.sub.3), and any combination thereof, or wherein the one or more solid inorganic bicarbonate compound is selected from the group consisting of calcium bicarbonate (Ca(HCO3)), magnesium bicarbonate (Mg(HCO.sub.3).sub.2), and lithium bicarbonate (LiHCO.sub.3), sodium bicarbonate (NaHCO.sub.3), potassium bicarbonate (KHCO.sub.3), caesium bicarbonate (CsHCO.sub.3), ammonium bicarbonate (NH4HCO3), carbonic acid (H2CO3), and any combination thereof.

180. The method of claim 174, wherein a concentration of the amino acid or the amino acid salt ranges from between about 0.1 wt % to about 20.0 wt % or between about 0.1 M and about 10.0 M.

181. The method of claim 167, wherein said reacting said one or more precursor compound with said one or more carbon dioxide capture solvent or capture additive occurs at a temperature below about 100 C.

182. The method of claim 167 further comprising: regenerating the one or more carbon dioxide capture solvent or capture additive.

183. The method of claim 167, wherein the one or more carbon dioxide capture solvent or capture additive repeatedly captures gaseous carbon dioxide and releases carbon dioxide to the one or more solid inorganic carbonate compound in a loop process, and wherein the solid inorganic carbonate compound in the loop process comprises one or more magnesium-bearing compound.

184. The method of claim 167 further comprising: providing a carbonate compound size modulator wherein the size modulator is a surfactant.

185. The method of claim 167 further comprising: producing one or more acid and one or more base by electrochemical decomposition of waste water.

186. A system for producing one or more solid inorganic carbonate compound or bicarbonate compound by capturing, converting, and storing carbon dioxide comprising: one or more precursor compound; one or more carbon dioxide capture solvent or capture additive; and a reactor, wherein said one or more precursor compound and said one or more carbon dioxide capture solvent or capture additive react in said reactor under conditions effective to produce one or more solid inorganic carbonate compound or inorganic bicarbonate compound.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] FIG. 1 is a schematic representation of the alkaline aqueous amine looping process for the carbon mineralization of magnesium oxide to produce magnesium carbonate.

[0020] FIG. 2 shows extent of carbon mineralization of MgO reacted with water, 10 wt %, 20 wt %, 30 wt %, and 50 wt % at 25 C., 50 C., 75 C., and 90 C. at P.sub.CO.sub.2=1 atm for 3 hrs and stirring rate of 300 rpm. Experiments were performed in duplicate.

[0021] FIGS. 3A-3B show the functional groups present in reacted solid and fluid obtained from MgO and MEA. FIG. 3A shows the identification of the functional groups present in the reacted solid. FIG. 3B shows the identification of the functional groups present in the reacted fluid obtained from reacting MgO with 30 wt % MEA at 50 C. with P.sub.CO.sub.2=1 atm for 3 hours and stirring rate of 300 rpm, using ATR-FTIR measurements.

[0022] FIGS. 4A-4B show a comparison of the morphological changes in MgO. FIG. 4A shows unreacted magnesium oxide. FIG. 4B shows MgO reacted with 30 wt % MEA. Experimental conditions for the images shown in FIG. 4B represent 50 C. with P.sub.CO.sub.2=1 atm for 3 hours and stirring rate of 300 rpm. The needle-shaped particles in FIG. 4B correspond to nesquehonite particles.

[0023] FIGS. 5A-5C show changes in the combined slit-smeared USAXS/SAXS data as MgO is reacted with CO.sub.2-loaded MEA. FIG. 5A shows changes to produce magnesium carbonate. FIGS. 5B and 5C respectively show the characteristic peak of lansfordite at q=0.5 .sup.1 and the normalized integrated intensity. The integrated intensity is normalized to the highest peak intensity which is noted at 385 minutes.

[0024] FIGS. 6A-6D show the Power law scop, pore size distribution, and cumulative pore volume. FIG. 6A shows a power law slope and radius of gyration (R.sub.g) values obtained from the fitting of experimental USAXS/SAXS curves in the q-range of 0.02-0.8 .sup.1. FIGS. 6B and 6C show the pore size distribution and cumulative pore volume for unreacted MgO and MgO reacted with 30 wt % MEA for 3 hours are represented, respectively. The pore size distributions were determined by using the BJH method on N.sub.2 desorption isotherm. FIG. 6C show the emergence of (001) lansfordite (MgCO.sub.3.Math.5H.sub.2O) (Giester et al., The Crystal Structure of Nesquehonite, MgCO.sub.3.Math.3H.sub.2O, From Lavrion, Greece, Mineral. Petrol. 70:153-163 (2000) and Ming et al., Synthesis and Characterization of Lansfordite and Nesquehonite, Soil Sci. Soc. Am. J. 49:1303-1308 (2010), both of which are hereby incorporated by reference in their entirety) peak from MgO.

[0025] FIGS. 7A-7D show results of magnesium carbonate particles. FIG. 7A SHOWS the in-situ cell for Grazing Incidence-Small Angle X-Ray Scattering (GI-SAXS) measurements. FIG. 7B shows a representative scattering image and FIG. 7B shows the scattering curve that correspond to the nucleation of magnesium carbonate particles on quartz (0 0 1) surface. FIG. 7D shows the size distribution obtained from fitting the scattering curve using the Guinier-Porod slope. The experiments were performed at 25 C. 0.1988 mL 30 wt % CO.sub.2-loaded MEA solution was injected into 5 mL 0.1 M Mg(NO.sub.3).sub.2 solution, which marked the beginning of the in-situ measurement.

[0026] FIGS. 8A-8C show identification of the functional groups present in the solid obtained after reacting MgO with water, 10 wt %, and 20 wt % MEA at 25 C., 50 C., 75 C., and 90 C. with P.sub.CO.sub.2=1 atm for 3 hours and stirring rate of 300 rpm5 rpm, using ATR-FTIR measurements.

[0027] FIGS. 9A-9C show identification of the functional groups present in the fluid obtained from reacting MgO with water (FIG. 9A), 10 wt % (FIG. 9B), and 20 wt % (FIG. 9C) MEA at 25 C., 50 C., 75 C., and 90 C. with P.sub.CO.sub.2=1 atm for 3 hours and stirring rate of 300 rpm5 rpm, using ATR-FTIR measurements.

[0028] FIG. 10 shows an experimental configuration of aqueous alkaline amine looping process for accelerated carbon mineralization.

[0029] FIG. 11 shows an experimental configuration of MgO reacting with CO.sub.2-loaded MEA in the USAXS/SAXS measurement.

[0030] FIG. 12 shows changes in the combined slit-smeared USAXS/SAXS data as MgO is reacted with CO.sub.2-loaded MEA to produce magnesium carbonate (full data set).

[0031] FIGS. 13A-13D shows intensity results. FIGS. 13A-13D shows experimental USAXS/SAXS scattering curves and fitted models for samples reacted for (FIG. 13A) 0 min, (FIG. 13B) 122 min, (FIG. 13C) 239 min, and (FIG. 13D) 385 min. The data were fitted using the Modelling-II tool in Irena package embedded in Igor Pro. The curve in FIG. 13A was modeled using two unified fit levels between the q-ranges of 0.001-0.02 .sup.1 and 0.02-0.8 .sup.1. FIGS. 13B-13D shows curves in panels besides two unified fit levels in q-ranges of 0.001-0.02 .sup.1 and 0.02-0.3 .sup.1, and a Lorentzian diffraction peak was also fitted between q values of 0.3-0.8 .sup.1.

[0032] FIG. 14 is a schematic representation of the alkaline aqueous amine looping process for the carbon mineralization, including the reactions of CO.sub.2 hydration, cation dissolution, CO.sub.2 capture by amino acids, amino acid regeneration, and carbonation formation.

[0033] FIG. 15 shows changes of aqueous species during CO.sub.2 capture using Na-glycinate determined using ATR-FTIR analyses. HCO.sub.3.sup. at 1005 cm.sup.1, 1300 cm.sup.1, and 1365 cm.sup.1. Milella et al., Estimating Speciation of Aqueous Ammonia Solutions of Ammonium Bicarbonate: Application of Least Squares Methods to Infrared Spectra, React. Chem. Eng. 4:1284-1302 (2019), which is hereby incorporated by reference in its entirety. CO.sub.3.sup.2 at 1395 cm.sup.1. Davis et al., A Vibrational-Spectroscopic Study of the Species Present in the CO.sub.2H.sub.2O System, J. Solution Chem. 1:329-339 (1972), which is hereby incorporated by reference in its entirety. NH.sub.2COO.sup. at 1120 cm.sup.1, 1413 cm.sup.1, and 1545 cm.sup.1. Milella et al., Estimating Speciation of Aqueous Ammonia Solutions of Ammonium Bicarbonate: Application of Least Squares Methods to Infrared Spectra, React. Chem. Eng. 4:1284-1302 (2019); Pretsch et al., Structure Determination of Organic Compounds, Berlin: Springer-Verlag 108 (2000); and Hisatsune, Low-temperature Infrared Study of Ammonium Carbamate Formation, Can. J. Chem. 62:945-948 (1984), all of which are hereby incorporated by reference in their entirety.

[0034] FIGS. 16A-16C show extent of carbonation of CaO (red) and CaSiO.sub.3 (blue) with 1 M sodium glycinate at different temperatures of 25, 50, 75, and 90 C. for 3 h in (FIG. 16A), with different concentration of 0, 0.5, 1, and 3 M sodium glycinate at 75 C. for 3 h in (FIG. 16B), with 1 M sodium glycinate at 75 C. for different reaction time of 1, 3, and 5 hr in (FIG. 16C). The experimental configuration is shown in FIG. 21. All the experiments are performed at P.sub.CO2=1 atm and a stirring rate of 300 rpm.

[0035] FIGS. 17A-17C show changes in the species present in the aqueous phase recovered after the carbon mineralization of CaO using ATR-FTIR analyses. FIGS. 17A-17C represent experiments performed to investigate the influence of temperature (FIG. 17A), amino acid salt concentration (FIG. 17B), and reaction time (FIG. 17C), respectively. Ramachandran et al., XRD, Thermal, FTIR and SEM Studies on Gel Grown -glycine Crystals, Cryst. Res. Technol. 42:73-77 (2007); Doki et al., Process Control of Seeded Batch Cooling Crystallization of the Metastable -Form Glycine Using an In-Situ ATR-FTIR Spectrometer and an In-Situ FBRM Particle Counter, Cryst. Growth. Des. 4:949-953 (2004); and Ahmed et al., Comparison Between FTIR and XPS Characterization of Amino Acid Glycine Adsorption onto Diamond-like Carbon (DLC) and Silicon Doped DLC, Appl. Surf Sci. 273:507-514 (2013), all of which are hereby incorporated by reference in their entirety.

[0036] FIGS. 18A-18C show changes in the species present in the aqueous phase recovered after the carbon mineralization of CaSiO.sub.3 using ATR-FTIR analyses. FIGS. 18A-18C represent experiments performed to investigate the influence of temperature (FIG. 18A), amino acid salt concentration (FIG. 18B), and reaction time (FIG. 18C), respectively. Ramachandran et al., XRD, Thermal, FTIR and SEM Studies on Gel Grown -glycine Crystals, Cryst. Res. Technol. 42:73-77 (2007); Doki et al., Process Control of Seeded Batch Cooling Crystallization of the Metastable -Form Glycine Using an In-Situ ATR-FTIR Spectrometer and an In-Situ FBRM Particle Counter, Cryst. Growth. Des. 4:949-953 (2004); and Ahmed et al., Comparison Between FTIR and XPS Characterization of Amino Acid Glycine Adsorption onto Diamond-like Carbon (DLC) and Silicon Doped DLC, Appl. Surf Sci. 273:507-514 (2013), all of which are hereby incorporated by reference in their entirety.

[0037] FIGS. 19A-19F show changes in the phases present in calcium oxide on carbon mineralization. FIG. 19A shows changes in the presence of 1 M sodium glycinate at 25, 50, 75, and 90 C. reacted for 3 hour. FIG. 19B shows different concentration of 0, 0.5, 1, and 3 M sodium glycinate at 75 C. for 3 hours. FIG. 19C shows results with 1 M sodium glycinate at 75 C. for different reaction time of 1, 3, and 5 hours. All the experiments are performed at P.sub.CO2=1 atm and a stirring rate of 300 rpm. Peaks are identified based on the crystallographic data reported for calcium oxide, calcite, vaterite, and aragonite. Crystallographic phases are identified based on the data presented in references. Mller et al., Crystal Structure Refinement: A Crystallographer's Guide to SHELXL, Oxford Scholarship Online (2010); Chessin et al., Positions and Thermal Parameters of Oxygen Atoms in Calcite, Acta Cryst. 18:689-693 (1965); Wang et al., Structure and Carbonited Orientation of Vaterite (CaCO.sub.3), Am. Minerl. 94:380-386 (2009); Dal Negro et al., Refinement of the Crystal Structure of Aragonite, Am. Mineral. 56:768-772 (1971); Primak et al., X-Ray Diffraction Studies of Systems Involved in the Preparation of Alkaline Earth Sulfide and Selenide Phosphors, J. Am. Chem. Soc. 70:2043-2046 (1948); and Petch, The Hydrogen Positions in Portlandite, Ca(OH).sub.2, as Indicated by the Electron Distribution, Acta Cryst. 14:950-957 (1961), all of which are hereby incorporated by reference in their entirety. The morphological changes of the CaO samples on carbonation are probed by SEM. FIG. 19D represents the unreacted CaO. FIG. 19E represents the reaction with H.sub.2O at 75 C. for 3 hours. FIG. 19F represents CaO after the reaction with 1 M sodium glycinate at 75 C. for 3 hr. Mller et al., Crystal Structure Refinement: A Crystallographer's Guide to SHELXL, Oxford Scholarship Online (2010); Wang et al., Structure and Carbonited Orientation of Vaterite (CaCO.sub.3), Am. Minerl. 94:380-386 (2009); Dal Negro et al., Refinement of the Crystal Structure of Aragonite, Am. Mineral. 56:768-772 (1971); Chessin et al., Positions and Thermal Parameters of Oxygen Atoms in Calcite, Acta Cryst. 18:689-693 (1965); and Maslen et al., X-ray Study of the Electron Density in Calcite, CaCO.sub.3, Acta Cryst. 49:636-641 (1993), all of which are hereby incorporated by reference in their entirety.

[0038] FIGS. 20A-20F show changes in the phases present in calcium silicate on carbon mineralization. FIG. 20A shows changes in the phases present in calcium silicate on carbon mineralization in the presence of 1 M sodium glycinate at 25, 50, 75, and 90 C. reacted for 3 hours. FIG. 20B shows changes with different concentration of 0, 0.5, 1, and 3 M sodium glycinate at 75 C. for 3 hours. FIG. 20C shows changes with 1 M sodium glycinate at 75 C. for different reaction time of 1, 3, and 5 hours. All the experiments are performed at P.sub.CO2=1 atm and a stirring rate of 300 rpm. Peaks are identified based on the crystallographic data reported for calcium silicate (or wollastonite), calcite, vaterite, and aragonite. Crystallographic phases are identified based on the data presented in Mller et al., Crystal Structure Refinement: A Crystallographer's Guide to SHELXL, Oxford Scholarship Online (2010); Chessin et al., Positions and Thermal Parameters of Oxygen Atoms in Calcite, Acta Cryst. 18:689-693 (1965); Wang et al., Structure and Carbonited Orientation of Vaterite (CaCO.sub.3), Am. Minerl. 94:380-386 (2009); Dal Negro et al., Refinement of the Crystal Structure of Aragonite, Am. Mineral. 56:768-772 (1971); Primak et al., X-Ray Diffraction Studies of Systems Involved in the Preparation of Alkaline Earth Sulfide and Selenide Phosphors, J. Am. Chem. Soc. 70:2043-2046 (1948); and Petch, The Hydrogen Positions in Portlandite, Ca(OH).sub.2, as Indicated by the Electron Distribution, Acta Cryst. 14:950-957 (1961), all of which are hereby incorporated by reference in their entirety. The morphological changes of the CaSiO.sub.3 samples on carbonation are probed by SEM. FIG. 20D represents the unreacted CaSiO.sub.3. FIG. 20E represents the reaction with H.sub.2O at 75 C. for 3 hours. FIG. 20F represents CaSiO.sub.3 after the reaction with 1 M sodium glycinate at 75 C. for 3 hr. Mller et al., Crystal Structure Refinement: A Crystallographer's Guide to SHELXL, Oxford Scholarship Online (2010); Wang et al., Structure and Carbonited Orientation of Vaterite (CaCO.sub.3), Am. Minerl. 94:380-386 (2009); Dal Negro et al., Refinement of the Crystal Structure of Aragonite, Am. Mineral. 56:768-772 (1971); Chessin et al., Positions and Thermal Parameters of Oxygen Atoms in Calcite, Acta Cryst. 18:689-693 (1965); and Maslen et al., X-ray Study of the Electron Density in Calcite, CaCO.sub.3, Acta Cryst. 49:636-641 (1993), all of which are hereby incorporated by reference in their entirety. FIG. 20E shows calcite crystals are identified as c.

[0039] FIG. 21 shows experimental set up and characterization.

[0040] FIGS. 22A-22C show changes in the bonds present in calcium oxide on carbon mineralization. FIG. 22A shows changes in the bonds present in calcium oxide on carbon mineralization in the presence of 1 M sodium glycinate at different temperatures of 25, 50, 75, and 90 C. for 3 hr. FIG. 22B shows changes with different concentration of 0, 0.5, 1, and 3 M sodium glycinate at 75 C. for 3 h. FIG. 22C shows changes with 1 M sodium glycinate at 75 C. for different reaction time of 1, 3, and 5 hr, represented by ATR-FTIR spectra. All the experiments are performed at P.sub.CO2=1 atm and a stirring rate of 300 rpm.

[0041] FIGS. 23A-23C show changes in the bonds present in calcium silicate on carbon mineralization. FIG. 23A shows changes in the presence of 1 M sodium glycinate at different temperatures of 25, 50, 75, and 90 C. for 3 h. FIG. 23B shows changes with different concentration of 0, 0.5, 1, and 3 M sodium glycinate at 75 C. for 3 h. FIG. 23C shows changes with 1 M sodium glycinate at 75 C. for different reaction time of 1, 3, and 5 hr, represented by ATR-FTIR spectra. All the experiments are performed at P.sub.CO2=1 atm and a stirring rate of 300 rpm.

[0042] FIG. 24 shows annual production rate in the United States and average calcium and magnesium concentrations in fly ash, cement kiln dust, steel slag, and red mud.

[0043] FIG. 25 shows a schematic representation of the TC.sup.3 reactor integrated with an absorber for CO.sub.2 capture to produce carbonates with inherent solvent regeneration.

[0044] FIG. 26 shows effect of temperature on the extent of carbon mineralization with MEA (50 wt % MEA for CaO, 30 wt % MEA for MgO and 50 wt % MEA for CaSiO.sub.3, 15 wt % solid precursors, p(CO.sub.2)=1 atm, 3 h stirring at 300 rpm).

[0045] FIG. 27 shows effect of temperature on the extent of carbon mineralization with 1.0 M sodium glycinate, 15 wt % solid precursors, p(CO.sub.2)=1 atm, 3 h stirring at 300 rpm.

[0046] FIG. 28 shows compressive strengths of cementitious composites prepared with no additives (control case), 20% Si-rich materials and 10% carbonated stainless steel slag (cSSS).

[0047] FIG. 29 shows annual emission rate of CO.sub.2 produced from each industrial sector and corresponding co-generated alkaline industrial wastes.

[0048] FIGS. 30A-30B shows a schematic representation of a Taylor-Couette reactor. FIG. 30A shows an image of a Taylor-Couette (T-C) reactor. FIG. 30B shows layout of flow visualization setup.

[0049] FIGS. 31A-31B show change in particle size distribution. FIG. 31A shows change in the particle size distributions (PSD) measured via DLS of precipitated calcium carbonate (PCC) formed under 0.02 L/min CO.sub.2 flowrate. FIG. 31B shows change in the particle size distributions (PSD) measured via DLS of precipitated calcium carbonate (PCC) formed under 0.1 L/min CO.sub.2 flowrate.

[0050] FIG. 32 shows chemical structures of aqueous solvents.

[0051] FIG. 33 is a schematic representation of acceleration carbon mineralization of mine tailings using CO.sub.2 captured from air and the electrochemical generation of acids and based from chloride brines.

[0052] FIG. 34 shows a schematic representation of the Taylor-Couette device representing the inlet and outlet streams. The reactions associated with the dissolution of CaO species, reactions with CO.sub.2-loaded amines to produce Ca-bearing carbonates.

DETAILED DESCRIPTION

[0053] A first aspect relates to a method of producing one or more solid inorganic carbonate compound by capturing, converting, and storing carbon dioxide. The method includes providing one or more precursor compound; providing one or more carbon dioxide capture solvent or capture additive; and reacting said one or more precursor compound with said one or more carbon dioxide capture solvent or capture additive under conditions effective to produce one or more solid inorganic carbonate compound.

[0054] As used herein, about or approximately, when used in connection with a numerical variable, generally refers to the value of the variable and to all values of the variable that are within the experimental error (e.g., within the 95% confidence interval for the mean) or within 10% of the indicated value, whichever is greater.

[0055] Where a range of values is provided, it is understood that each intervening value, to the tenth of the unit of the lower limit unless the context clearly dictates otherwise, between the upper and lower limit of that range and any other stated or intervening value in that stated range, is encompassed within the present disclosure. The upper and lower limits of these smaller ranges may independently be included in the smaller ranges and are also encompassed within the present disclosure, subject to any specifically excluded limit in the stated range. Where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included in the present disclosure.

[0056] Certain ranges are presented herein with numerical values being preceded by the term about. The term about is used herein to provide literal support for the exact number that it precedes, as well as a number that is near to or approximately the number that the term precedes. In determining whether a number is near to or approximately a specifically recited number, the near or approximating unrequited number may be a number, which, in the context in which it is presented, provides the substantial equivalent of the specifically recited number.

[0057] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present disclosure belongs. Although any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present disclosure, representative illustrative methods and materials are now described.

[0058] It is noted that, as used herein and in the appended claims, the singular forms a, an, and the include plural references unless the context clearly dictates otherwise. It is further noted that the claims may be drafted to exclude any optional element. As such, this statement is intended to serve as antecedent basis for use of such exclusive terminology as solely, only and the like in connection with the recitation of claim elements, or use of a negative limitation.

[0059] As will be apparent to those of skill in the art upon reading this disclosure, each of the individual embodiments described and illustrated herein has discrete components and features which may be readily separated from or combined with the features of any of the other several embodiments without departing from the scope or spirit of the invention. Any recited method can be carried out in the order of events recited or in any other order, which is logically possible.

[0060] The present disclosure generally relates new methods, processes, and systems for producing solid inorganic carbonates by capture, conversion, storage, extraction, reduction, disposal, or sequestration of carbon dioxide (CO.sub.2), particularly from the air, and involves new processes to reduce or eliminate CO.sub.2, e.g., greenhouse gas CO.sub.2, from the environment. The processes described herein are aimed at effective and efficient carbon management, including cost effectiveness and efficient heat management. Thus, the processes and products of the present disclosure provide useable and economically viable technologies for tackling and handling the escalating problem of global warming.

[0061] The sequestration of carbon dioxide gas in repositories that are isolated from the atmosphere is a developing technology that is widely recognized as an essential element in global attempts to reduce carbon dioxide emissions to the atmosphere. The rapid increase in atmospheric carbon dioxide concentrations is of concern due to its properties as greenhouse gas and its contribution to the phenomena of global warming and climate change.

[0062] As described herein, the methods and systems include capturing, converting, and storing carbon dioxide (CO.sub.2). The source of CO.sub.2 may be any convenient CO.sub.2 source. The CO.sub.2 source may be a gas, a liquid, a solid (e.g., dry ice), a supercritical fluid, or CO.sub.2 dissolved in a liquid. In some embodiments, the CO.sub.2 source is a gaseous CO.sub.2 source. The gaseous stream may be substantially pure CO.sub.2 or comprise multiple components that include CO.sub.2 and one or more additional gases and/or other substances such as ash and other particulates. The CO.sub.2 may be, for example, anthropogenic, or originating from human activity. In some embodiments, the gaseous CO.sub.2 source may be a waste gas stream (for example, a by-product of an active process of the industrial plant) such as exhaust from an industrial plant. The nature of the industrial plant may vary and may include, for example, power plants, chemical processing plants, mechanical processing plants, refineries, cement plants, steel plants, and other industrial plants that produce CO.sub.2 as a by-product of fuel combustion or another processing step.

[0063] Waste gas streams comprising CO.sub.2 may include both reducing (e.g., syngas, shifted syngas, natural gas, hydrogen, and the like) and oxidizing condition streams (e.g., flue gases from combustion). Waste gas streams that may be useful in accordance with the present disclosure may include oxygen-containing combustion industrial plant flue gas, for example, from coal or another carbon-based fuel with little or no pretreatment of the flue gas; turbo charged boiler product gas; coal gasification product gas; shifted coal gasification product gas; anaerobic digester product gas; wellhead natural gas stream; reformed natural gas or methane hydrates; and the like. Combustion gas from any convenient source may be used in methods and systems of the present disclosure. In some embodiments, combustion gases in post-combustion effluent stacks of industrial plants such as power plants, cement plants, and coal processing plants may be used.

[0064] Thus, a waste stream may be produced from a variety of different types of industrial plants. Suitable waste streams in accordance with the present disclosure may include waste streams produced by industrial plants that combust fossil fuels (e.g., coal, oil, natural gas) and anthropogenic fuel products of naturally occurring organic fuel deposits (e.g., tar sands, heavy oil, oil shale). In some embodiments, waste streams suitable for systems and methods of the present disclosure are sourced from a coal-fired power plant, such as a pulverized coal power plant, a supercritical coal power plant, a mass burn coal power plant, or a fluidized bed coal power plant. In some embodiments, the waste stream is sourced from gas or oil-fired boiler and steam turbine power plants, gas or oil-fired boiler simple cycle gas turbine power plants, or gas or oil-fired boiler combined cycle gas turbine power plants. In some embodiments, waste streams produced by power plants that combust syngas, or, gas that is produced by the gasification of organic matter, for example, coal, or biomass may be used. In other embodiments, waste streams from integrated gasification combined cycle plants may be used. In other embodiments, waste streams produced by Heat Recovery Steam Generator plants may be used in accordance with systems and methods of the present disclosure.

[0065] Waste streams produced by cement plants are also suitable sources of carbon dioxide for the systems and methods of the present disclosure. Cement plant waste streams include waste streams from both wet process and dry process plants, which plants may employ shaft kilns or rotary kilns, and may include pre-calciners. These industrial plants may burn a single fuel, or may burn two or more fuels sequentially or simultaneously. Other industrial plants such as smelters and refineries are also useful sources of waste streams that include carbon dioxide.

[0066] Industrial waste gas streams may contain carbon dioxide as the primary non-air derived component, or may, especially in the case of coal-fired power plants, contain additional components such as nitrogen oxides (NOx), sulfur oxides (SOx), and one or more additional gases. Additional gases and other components may include carbon monoxide, mercury and other heavy metals, and dust particles, for example, from calcining and combustion processes. Additional components in the gas stream may also include halides like hydrogen chloride and hydrogen fluoride; particulate matter such as fly ash, dusts, and metals including arsenic, beryllium, boron, cadmium, chromium, chromium VI, cobalt, lead, manganese, mercury, molybdenum, selenium, strontium, thallium, and vanadium; and organics such as hydrocarbons, dioxins, and PAH compounds. Suitable gaseous waste streams that may be treated have, for example, CO.sub.2 present in amounts of 10 ppm to 1,000,000 ppm, for example, about 10 ppm to about 200,000 ppm, including about 1000 ppm to about 200,000 ppm, about 2000 ppm to about 200,000 ppm, about 3000 ppm to about 200,000 ppm, about 4000 ppm to about 200,000 ppm, about 5000 ppm to about 200,000 ppm, about 6000 ppm to about 200,000 ppm, about 7000 ppm to about 200,000 ppm, about 8000 ppm to about 200,000 ppm, about 9000 ppm to about 200,000 ppm, and about 10,000 ppm to about 200,000 ppm, or any amount between 10 ppm and 1,000,000 ppm. The waste streams, particularly various waste streams of combustion gas, may include one or more additional components, for example, water, NOx (mononitrogen oxides: NO and NO.sub.2), SOx (monosulfur oxides: SO, SO.sub.2 and SO.sub.3), VOC (volatile organic compounds), heavy metals such as mercury, and particulate matter (particles of solid or liquid suspended in a gas).

[0067] The precursor compound as described herein includes any compound that is capable of reacting with one or more CO.sub.2 capture solvents and/or capture additives under conditions effective to produce one or more solid inorganic carbonate compounds and/or one or more solid inorganic bicarbonate compounds. For example, the precursor compounds described herein may include any non-carbonate metal species and/or non-bicarbonate metal species. In one embodiment, the one or more precursor compounds are a non-carbonate metal species or a non-bicarbonate metal species.

[0068] The precursor compound may be a solid compound or a liquid compound. In one embodiment, the one or more precursor compound is a solid precursor compound or a liquid precursor compound. In one embodiment, the one or more precursor compound includes, but is not limited to, a silicate compound, an oxide compound, a chloride compound, a hydroxide compound, a nitrate compound, a nitrite compound, a sulfite compound, and a sulfate compound, and/or any combination thereof.

[0069] The precursor compound described herein may, in one embodiment, may be a silicate compound, an oxide compound, a chloride compound, a hydroxide compound, a nitrate compound, a nitrite compound, a sulfite compound, sulfate compound, or a combination thereof. The one or more a silicate compound, an oxide compound, a chloride compound, a hydroxide compound, a nitrate compound, a nitrite compound, a sulfite compound, or sulfate compound as described herein may include any compound that contains a calcium-, magnesium-, lithium-, or aluminum-bearing silicate, or a calcium-, magnesium-, lithium-, or aluminum-bearing oxide group, or a combination of a calcium-, magnesium-, lithium-, or aluminum-bearing silicate and/or a calcium-, magnesium-, lithium-, or aluminum-bearing oxide group. In one embodiment, the one or more calcium- or magnesium-bearing compounds may be calcium-bearing silicate, magnesium-bearing silicate (e.g., Mg.sub.2SiO.sub.4), lithium-bearing silicate, or aluminum-bearing silicate, or may be a calcium-bearing hydroxide, magnesium-bearing hydroxide, lithium-bearing hydroxide, or aluminum-bearing hydroxide.

[0070] In one embodiment, the one or more calcium-, magnesium-, lithium-, or aluminum-bearing compounds may be a synthetic compound or, alternatively, the one or more calcium-, magnesium-, lithium-, or aluminum-bearing compounds may be a naturally-occurring compound. Alternatively, the one or more calcium-, magnesium-, lithium-, or aluminum-bearing compounds may be a combination of synthetic and naturally-occurring compounds. High purity silica-free Ca- and Mg-hydroxides may, in one embodiment, be synthesized from CaSiO.sub.3 and Mg.sub.2SiO.sub.4, respectively. In one embodiment, the one or more precursor compound is a calcium-, magnesium-, lithium-, or aluminum-bearing silicate or a calcium-, magnesium-, lithium-, or aluminum-bearing oxide. In one embodiment, the one or more precursor compound comprises coal, fly ash, steel slag, minerals, mine-tailings, industrial residues, or rocks. The precursor compound may from a waste gas stream, a liquid waste stream, or solid waste. In one embodiment, the one or more precursor compound is selected from the group consisting of CaO, CaSiO.sub.3, MgO, LiCl, MgCl.sub.2, CaCl.sub.2, NaCl, heterogeneous mineral and rock matrices, and combinations thereof.

[0071] The calcium-, magnesium-, lithium-, or aluminum-bearing silicate and/or hydroxide as described herein includes silicates and/or hydroxides comprising magnesium, calcium, lithium, aluminum, or any combination thereof. Part of the magnesium, calcium, lithium, or aluminum may be replaced by other metals, for example iron or manganese. Any magnesium, calcium, lithium, or aluminum silicate or hydroxide belonging to the group of sheet silicates may be used in the methods and processes of the present disclosure. Examples of suitable silicates or hydroxides are serpentine, talc, and sepiolite. Serpentine and talc are examples of useful silicate hydroxides.

[0072] The methods and processes described herein may use, for example, silicate-based minerals or materials. A non-limiting example of a silicate based material is serpentine, which occurs naturally and may be generally described by the formula of X.sub.2-3Si.sub.2O.sub.5(OH).sub.4, where X is selected from the following: Mg, Ca, Fe.sup.2+, Fe.sup.3+, Ni, Al, Zn, and Mn, where the serpentine material is a heterogeneous mixture comprised primarily of magnesium hydroxide and silica. Other examples of silicate-based minerals include, but are not limited to, olivine, which is a natural magnesium-iron silicate ((Mg, Fe).sub.2SiO.sub.4), and can be generally described by the formula X.sub.2(SiO.sub.4).sub.n, where X is selected from Mg, Ca, Fe.sup.2+, Fe.sup.3+, Ni, Al, Zn, and Mn, and n=2 or 3; and a calcium silicate, for example wollastonite, which naturally occurs in metamorphic rocks. The silicate-based minerals may be used individually or in combination with each other. Additionally, the silicate based materials may be found in nature or may be manufactured. Examples of industrial by-products include but are not limited to waste cement and calcium-rich fly ash.

[0073] Slag as described herein includes conventional commercial slag which includes or comprises of dicalcium silicate. Any other slag known commercially is within the scope of this application. Accordingly, slag used herein, may contain between about 25-60 wt % CaO. Slag solid as described herein includes solid slag. Typically, slag is a large-grain solid which may be milled down to a smaller size. The size of the grain in slag may vary and may be between 1 micron-5 mm; or between 1 micron-1 mm; or between 1 micron-500 micron; or between 1 micron-100 micron. Slag and slag solid may be used interchangeably herein.

[0074] In some embodiments, the silica present in methods and processes of the present disclosure is provided by material comprising metal silicates or a combination of materials comprising metal silicates with supplemental sources of silica (e.g., fly ash, cement kiln dust, and/or other anthropogenic sources).

[0075] Rock, a naturally occurring solid aggregate comprising minerals and/or mineraloids, is suitable for use in the present disclosure, particularly rock comprising magnesium and/or calcium (e.g., peridotite, basalt, gabbro, diabase) that, upon processing like size reduction or digestion, provides one or more calcium- or magnesium-bearing compounds. Rock may also provide silica content to compounds of the present disclosure. Minerals, which have characteristic compositions with highly ordered atomic structure and distinct physical properties, may be useful in some embodiments. Minerals comprising magnesium and/or calcium may also provide silicates (e.g., metal silicates, which contain at least one metal along with silicon such as such as calcium silicates, magnesium silicates, aluminosilicates, iron-bearing silicates, and mixtures thereof) that, upon processing, provide silica to compositions of the present disclosure. As rock may be used in the present disclosure, both pure or impure minerals are suitable for the methods and processes of the present disclosure.

[0076] Many different materials comprising metal silicates are suitable for use in accordance with the present disclosure, including naturally occurring materials comprising metal silicates such as those present in rocks, minerals, and mineral-rich clays. Metal silicates that may be used in the present disclosure include, but are not limited to, orthosilicates, inosilicates, phyllosilicates, and tectosilicates. Orthosilicates may include, for example, olivine group minerals ((Mg,Fe).sub.2SiO.sub.4). Inosilicates, which are often referred to as chain silicates, include, for example, single chain inosilicates such as pyroxene group minerals (XY(Si,Al).sub.2O.sub.6), where X represents ions of calcium, sodium, iron (e.g., Fe.sup.2+), or magnesium and Y represents ions of smaller size, like chromium, aluminum, iron (e.g., Fe.sup.3+ or Fe.sup.2+), magnesium, manganese, scandium, titanium, and vanadium, and where pyroxene group minerals richer in magnesium may be used in some embodiments. Single chain inosilicates may also include, for example, pyroxenoid group minerals such as wollastonite (CaSiO.sub.3), commonly in contact-metamorphosed limestone, and pectolite (NaCa.sub.2(Si.sub.3O.sub.8)(OH)), which are also suitable for use in the present disclosure. Double chain inosilicates may include, for example, amphibole group minerals such as anthophyllite ((Mg,Fe).sub.7Si.sub.8O.sub.22(OH).sub.2). Phyllosilicates (i.e., sheet silicates) include, for example, serpentine group minerals (e.g., antigorite, chrysotile, and/or lizardite polymorphs of serpentine), phyllosilicate clay minerals (e.g., montmorillonite and talc), and mica group minerals (e.g., biotite). Tectosilicates (i.e., framework silicates), which are aluminosilicates (with the exception of quartz group minerals), include, for example, plagioclase feldspars such as labradorite and anorthite.

[0077] Mafic and ultramafic minerals (i.e., silicate-containing minerals rich in magnesium and iron, sometimes referred to as magnesium silicates) are examples of metal silicates described above. As such, mafic minerals and ultramafic minerals, and products or processed forms thereof, are also suitable for use in accordance with the present disclosure. Mafic and ultramafic rocks, which include mafic and ultramafic minerals, are suitable for use in accordance with the present disclosure as well. Such rocks may include, but are not limited to, pyroxenite, troctolite, dunite, peridotite, basalt, gabbro, diabase, and soapstone. Common rock-forming mafic minerals include olivine, pyroxene, amphibole, and biotite. Significant masses of olivine- and serpentine-bearing rocks exist around the world, particularly in ultramafic complexes, and in large serpentinite bodies. As described herein, serpentine is an abundant naturally occurring mineral having minor amounts of elements such as chromium, manganese, cobalt, and nickel. Serpentine may refer to any of more than twenty varieties belonging to the serpentine group. Olivine is a naturally occurring magnesium-iron silicate ((Mg,Fe).sub.2SiO.sub.4), which ranges from forsterite (Fo) (MgSiO.sub.4) to fayalite (Fa) (Fe.sub.2SiO.sub.4). Wollastonite is a naturally occurring calcium silicate that may be used in accordance with the present disclosure.

[0078] Mg(OH).sub.2, in one embodiment, may be produced by recycling ammonium sulphate salts as the extraction agents with magnesium silicates. In this extraction route, a solid-solid reaction of ammonium sulfate with magnesium silicate-bearing minerals such as serpentine (e.g., Mg.sub.3Si.sub.2O.sub.5(OH).sub.4) may be completed at temperature in the range of 400 C.-550 C. extracts Mg into magnesium sulfate (MgSO.sub.4). The gaseous by-products may include ammonia, water vapor, and sulfur dioxide. Ammonia and water may be recovered to produce ammonium hydroxide. Magnesium sulfate and ammonia hydroxide may be reacted in the aqueous phase at pH 11-12 and room temperature to produce high purity magnesium hydroxide and regenerate ammonium sulfate. In one embodiment, iron may be precipitated as FeO(OH) at pH 8-9.

[0079] The one or more silicate compound, an oxide compound, a chloride compound, a hydroxide compound, a nitrate compound, a nitrite compound, a sulfite compound, and a sulfate compound (e.g., Ca- and Mg-hydroxides or silicates) may have a varying and adjustable pH. For example, the pH of the calcium- or magnesium-bearing compounds may be 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12, or any amount therebetween and may be adjusted. For example, in various embodiments, the precipitation of silica may occur at pH 2-3, iron oxide precipitation may occur at pH of 8-9 (if iron is present in the silicates), and precipitation of hydroxides may occur at a pH of 11-12.

[0080] The methods and systems described herein further include one or more carbon dioxide capture solvent or capture additive. As described herein, a carbon dioxide capture solvent or capture additive may include a carbon dioxide loaded aqueous solvent such as sodium glycinate, monoethanoamine (MEA), diethanolamine (DEA), piperazine (PZ), 2-amino-2-methyl-1-propanol (AMP) and methyl diethanolamine (MDEA). In one embodiment, the one or more carbon dioxide capture solvent or capture additive comprises an amine, an amino acid, an amino acid salt, an amine functional group for carbon dioxide capture, or a carboxyl functional group for carbon dioxide capture. Table 1 provides a list of examples of carbon dioxide capture solvent or capture additive.

TABLE-US-00001 TABLE 1 List of solvents for CO.sub.2 capture Monoethanolamine 3-(Aminomethyl) piperidine 4-(3-Aminopropyl) morpholine Diethanolamine (3AM-PD) (APMor) Monoethanoldiamine N-methyl-diethanolamine 1-(2-Hydroxyethyl) piperazine 2-Amino-2-methyl-1-propanol (MDEA) (HEP) Imidazole 2-Amino-2-methyl-1- 1,2-Bis(2-aminoethoxy) ethane 1-Methylimidazole propanol (AMP) (BAEE) 2-Methylimidazole 1,3-Diaminopentane (1,3- Bis[2-(N,N-dimethylamino) 4(5)-Methylimidazole DAP) ethyl] ether (BDMAEE) 2-Ethylimidazole 2-(Aminomethyl) piperidine 3-(Dimethylamino)-1,2- 1,2-Dimethylimidazole (2AM-PD) propanediol (DMA-PDL) 2-Ethyl 4-methylimidazole 4-Aminopiperidine (4A-PD) 3-(Diethylamino)-1,2- Triethylenediamine (TEDA) Diisopropanolamine (DIPA) propanediol (DEA-PDL) 3-Quinuclidinol (3-QD) 2-Amino-1-butanol (2-AB) 2-(Diisopropylamino) ethanol 4-Hydroxy-1-methylpiperidine 2-Amino-2-ethyl-1,3- (DIPAE) (HMPD) propanediol (AEPD) 3-Methoxypropylamine (MOPA) 1-(2-Hydroxyethyl) piperidine 2-(Isopropylamino) ethanol 2-(2-dimethylaminoethoxy)- (HEPD) (IPAE) ethanol 4-(2-Hydroxyethyl) morpholine N,N-Dimethylglycine (DMG) 3-dimethyl-amino-propan-1-ol (HEMor) L-Proline (L-Pro) Pyridine Tropine L-Proline (L-Pro) N,N,N,N- Dimethylaminoethoxyethanol 4-Hydroxy-L-proline (HL- tetramethylethylenediamine (DMAEE) Pro) (TMEDA) 2-(Diethylamino) ethanol Benzylamine Piperazine (DEEA) N-benzylethanolamine 4-(Aminomethyl) piperidine (4AM-PD) 2,2,6,6-tetramethyl-piperidin- 4-one

[0081] In one embodiment, when the carbon dioxide capture solvent or capture additive comprises an amine, the amine is selected from the group consisting of monoethanolamine, piperazine, diethanolamine, 2-amino-2-methyl-1-propanol, and methyldiethanolamine. In one embodiment, the carbon dioxide capture solvent or capture additive is not monoethanolamine. In another embodiment, when the carbon dioxide capture solvent or capture additive includes an amino acid or amino acid salt, that amino acid or amino acid salt is a glycine compound. In one embodiment, the glycine compound is glycinate. In yet another embodiment, the glycinate is sodium glycinate or potassium glycinate.

[0082] The concentration of the carbon dioxide capture solvent or capture additive may be any concentration suitable for the methods and processes of the present disclosure. In one embodiment, where the carbon dioxide capture solvent or capture additive includes an amino acid or amino acid salt, the concentration of the amino acid or the amino acid salt ranges from between about 0.1 wt % to about 50.0 wt %. For example, the amino acid or the amino acid salt may be about 0.1 wt %, about 0.5 wt %, about 1.0 wt %, about 2.0 wt %, about 3.0 wt %, about 4.0 wt %, about 5.0 wt %, about 6.0 wt %, about 7.0 wt %, about 8.0 wt %, about 9.0 wt %, about 10.0 wt %, about 11.0 wt %, about 12.0 wt %, about 13.0 wt %, about 14.0 wt %, about 15.0 wt %, about 16.0 wt %, about 17.0 wt %, about 18.0 wt %, about 19.0 wt %, about 20.0 wt %, about 25.0 wt %, about 30.0 wt %, about 35.0 wt %, about 40.0 wt %, about 45.0 wt %, or about 50.0 wt % of the capture solvent or capture additive, or any amount therebetween. In one embodiment, the concentration of the amino acid or the amino acid salt is between about 0.1 M and about 10.0 M. For example, the amino acid salt may be about 0.1 M, 0.2 M, 0.3 M, 0.4 M, 0.5 M, 0.6 M, 0.7 M, 0.8 M, 0.9 M, 1.0 M, 2.0 M, 3.0 M, 4.0 M, 5.0 M, 6.0 M, 7.0 M, 8.0 M, 9.0 M, 10.0 M, or any amount therebetween.

[0083] In one embodiment, where the carbon dioxide capture solvent or capture additive includes an amine, the concentration of the amine is between about 0 wt % to about 50 wt %. For example, the amine may be about 0 wt %, 0.5 wt %, 1.0 wt %, 2.0 wt %, 3.0 wt %, 4.0 wt %, 5.0 wt % 6.0 wt % 7.0 wt % 8.0 wt % 9.0 wt % 10 wt %, 15 wt %, 20 wt %, 25 wt %, 30 wt %, 35 wt %, 40 wt %, 45 wt %, 50 wt %, or any amount therebetween.

[0084] The CO.sub.2 capture solvent and/or capture additive may, in one embodiment, be aqueous solvent with amine dissolved therein. The CO.sub.2 capture solvent and/or capture additive may, in one embodiment, further comprise providing one or more additional solvents. The additional solvent may be used to create a liquid or aqueous solution. The one or more additional solvent may be, for example, water.

[0085] The methods and systems described herein are effective to produce one or more solid inorganic carbonate compounds and/or one or more solid inorganic bicarbonate compounds. In one embodiment, the one or more solid inorganic carbonate compounds and/or one or more solid inorganic bicarbonate compounds may be, for example, magnesite, hydrated magnesium carbonates, calcite, vaterite, aragonite, lithium carbonate, CaCO.sub.3, MgCO.sub.3, LiCO.sub.3, or any combination thereof.

[0086] The solid inorganic carbonate compounds of the present disclosure may be, for example, magnesite, hydrated magnesium carbonates, calcite, vaterite, aragonite, calcium carbonate (CaCO.sub.3), magnesium carbonate (MgCO.sub.3), and lithium carbonate (LiCO.sub.3), sodium carbonate (Na.sub.2CO.sub.3), potassium carbonate (K.sub.2CO.sub.3), caesium carbonate (Cs.sub.2CO.sub.3), ammonium bicarbonate ((NH.sub.4).sub.2HCO.sub.3), and any combination thereof.

[0087] A calcium-bearing carbonate may include, for example, calcite, vaterite, and/or aragonite. A desirable feature of the disclosed reaction is to optimize the conditions to allow formation of desirable and stable carbonates. Calcite, for example, is a stable form and desirable product. A magnesium-bearing carbonate may include, for example, magnesite and hydrated magnesium carbonates. Magnesium, for example, is stable and desirable product.

[0088] In one embodiment, the method further includes producing water soluble carbonates via anti-solvent crystallization. Water soluble carbonates as described herein may include but are not limited to NaHCO.sub.3 and KHCO.sub.3.

[0089] The reaction conditions used in the methods and systems described herein may occur at a temperature range of between about 0 C. to about 200 C., in particular 100 C. or below, or between about 0 C. and about 100 C. For example, the temperature range may be between about 0 C. to about 200 C.; between about 0 C. and about 175 C.; between about 0 C. and about 150 C.; between about 0 C. and about 125 C.; between about 0 C. and about 100 C.; between about 25 C. and about 175 C.; between about 25 C. and about 150 C.; between about 25 C. and about 125 C.; between about 25 C. and about 100 C.; and any range therebetween. In one embodiment, the temperature may be 100 C. or less. For example, the temperature range may be between about 50 C. and about 100 C.; between about 0 C. and about 50 C.; between about 25 C. and about 75 C.; and any range therebetween. The temperature may be, for example, about 1 C., about 5 C., about 10 C., about 15 C., about 20 C., about 25 C., about 30 C., about 35 C., about 40 C., about 45 C., about 50 C., about 55 C., about 60 C., about 65 C., about 70 C., about 75 C., about 80 C., about 85 C., about 90 C., about 95 C., about 100 C., or any temperature therebetween. In one embodiment, reacting said one or more precursor compounds with said one or more CO.sub.2 capture solvents and/or capture additives occurs at a temperature below 100 C. In one embodiment, said reacting occurs at a temperature between about 25 C. and about 90 C.

[0090] The reaction conditions used in the methods and systems described herein may occur at a pressure range of between about 0.01 atm and about 10 atm. In one embodiment, reacting said one or more precursor compound with said one or more CO.sub.2 capture solvents and/or capture additives occurs at a pressure of between about 0.1 atm and about 10 atm. The pressure may be, for example, between about 0.01 atm and about 25 atm; between about 0.01 atm and about 20 atm; between about 0.01 atm and about 15 atm; between about 0.01 atm and about 10 atm; between about 0.01 atm and about 5 atm; between about 0.01 atm and about 4 atm; between about 0.01 atm and about 3 atm; between about 0.01 atm and about 2 atm; between about 0.01 atm and about 1.5 atm; between about 0.01 atm and about 1.25 atm; between about 0.01 atm and about 1.0 atm; between about 0.5 atm and about 1.5 atm; between about 0.75 atm and about 1.25 atm, or any pressure therebetween. The pressure may, for example, be between 0.5 atm and about 10 atm; between about 0.5 atm and about 9 atm; between about 0.5 atm and about 8 atm; between about 0.5 atm and about 7 atm; between about 0.5 atm and about 6 atm; between about 0.5 atm and about 5 atm; between about 0.5 atm and about 1.5 atm; between about 1 atm and 10 atm; between about 0.1 atm and about 5 atm; between about 5 atm and about 10 atm, or any pressure therebetween. The pressure may be, for example about 0.1 atm, about 0.2 atm, about 0.3 atm, about 0.4 atm, about 0.5 atm, about 0.6 atm, about 0.7 atm, about 0.8 atm, about 0.9 atm, about 1 atm, about 1.5 atm, about 2 atm, about 2.5 atm, about 3 atm, about 3.5 atm, about 4 atm, about 4.5 atm, about 5 atm, about 5.5 atm, about 6 atm, about 6.5 atm, about 7 atm, about 7.5 atm, about 8 atm, about 8.5 atm, about 9 atm, about 9.5 atm, about 10 atm, or any pressure therebetween. In one embodiment, the pressure may be at or about 1 atm. In one embodiment, said reacting occurs at about atmospheric pressure. Alternatively, the pressure may be between about 10 atm and about 25 atm; between about 10 atm and about 20 atm; between about 10 atm and about 15 atm; between about 15 atm and about 30 atm; between about 20 atm and about 30 atm; between about 25 atm and about 30 atm, and/or any range therebetween. In other examples, the pressure may be as high as 200 atm.

[0091] In the methods and processes described herein, in one embodiment, the reacting occurs under continuous stirring conditions. The rate of stirring may be, for example, between about 10 rpm and about 500 rpm. For example, the rate of stirring may be between about 15 rpm and about 475 rpm; between about 25 rpm and about 450 rpm; between about 50 rpm and about 425 rpm; between about 75 rpm and about 400 rpm; between about 100 rpm and about 375 rpm; between about 125 rpm and about 350 rpm; between about 150 rpm and about 325 rpm; between about 175 rpm and about 300 rpm; between about 200 rpm and about 400 rpm; between about 225 rpm and about 375 rpm; between about 250 rpm and about 350 rpm; between about 275 rpm and about 325 rpm, and/or any range therebetween. In one embodiment, the continuous stirring conditions occur at a rate between about 250 rpm and about 350 rpm. In one embodiment, the continuous stirring conditions occur at a rate between about 250 rpm and about 350 rpm. For example, the rate may be about 250 rpm, about 275 rpm, about 300 rpm, about 325 rpm, about 350 rpm, or any rate therebetween. Alternatively, the reacting may occur in non-continuous stirring conditions or intermittent stirring conditions.

[0092] The reaction conditions used in the methods described herein may occur for varying periods of time. Reaction conditions may occur for between about 30 minutes and about 25 hours, for example, between about 1 hour and about 25 hours; between about 5 hours and about 20 hours; between about 10 hours and about 15 hours; between about 1 hours and about 10 hours; between about 1 hour and about 9 hours; between about 1 hour and about 8 hours; between about 1 hour and about 7 hours; between about 1 hour and about 6 hours; between about 1 hour and about 5 hours; between about 1 hour and about 4 hours; between about 1 hour and about 3 hours; between about 1 hour and about 2 hours; between about 2 hours and about 7 hours; and/or any range therebetween. For example, the reaction conditions may occur for about 1 hour, about 2 hours, about 3 hours, about 4 hours, about 5 hours, about 6 hours, about 7 hours, about 8 hours, about 9 hours, and/or any amount of time therebetween. In one embodiment of the methods and processes described herein, there is a reaction time of between about 1 hour and about 15 hours or any amount of time therebetween. For example, the reaction time may be about 1 hour, about 1.5 hours, about 2 hours, about 2.5 hours, about 3 hours, about 3.5 hours, about 4 hours, about 4.5 hours, about 5 hours, about 5.5 hours, about 6 hours, about 6.5 hours, about 7 hours, about 7.5 hours, about 8 hours, about 8.5 hours, about 9 hours, about 9.5 hours, about 10 hours, about 10.5 hours, about 11 hours, about 11.5 hours, about 12 hours, about 12.5 hours, about 13 hours, about 13.5 hours, about 14 hours, about 14.5 hours, about 15 hours, or any amount of time therebetween.

[0093] The reaction conditions may occur in a single step or in two or more steps. In one embodiment, the reacting occurs in a single step. In another embodiment, the reacting occurs in two or more steps and wherein carbon dioxide capture is decoupled from production of one or more carbonate compound. In one embodiment, the one or more carbon dioxide capture solvent or capture additive is loaded with carbon dioxide.

[0094] The method may in certain examples regenerate a CO.sub.2 capture solvent and/or a capture additive. In one embodiment, the method further comprises regenerating the one or more CO.sub.2 capture solvents and/or capture additives.

[0095] In one embodiment, the method further includes providing one or more additional solvents. In another embodiment, the method further includes regenerating the one or more carbon dioxide capture solvent or capture additive. In one embodiment, the method further includes capturing carbon dioxide via the one or more carbon dioxide capture solvent or capture additive under conditions effective to form a carbon dioxide loaded state of the one or more carbon dioxide capture solvent or capture additive. In another embodiment, the one or more carbon dioxide capture solvent or capture additive changes from a carbon dioxide loaded state to a carbon dioxide release state upon converting carbon dioxide to one or more solid inorganic carbonate compound. In yet another embodiment, the one or more carbon dioxide capture solvent or capture additive repeatedly captures gaseous carbon dioxide and releases carbon dioxide to the one or more solid inorganic carbonate compound in a loop process.

[0096] As described herein, the methods and process may further include, in one embodiment, providing a carbonate compound size modulator. The carbonate compound size modulator may be a surfactant. In one embodiment, the surfactant is a cationic surfactant. Suitable cationic surfactants include, but are not limited to, C.sub.12-C.sub.18 alkyl dimethylammonium acetamide, C.sub.12-C.sub.18 alkyl trimethylammonium, and mixtures thereof. Examples of such cationic surfactants are cetyldimethylammonium acetamide, octadecyl-dimethylammonium acetamide, tetradecyl-dimethylammonium acetamide, dodecyl-dimethylammonium acetamide, cetyltrimethylammonium, octadcecyl-trimethylammonium, tetradecyl-trimethylammonium, dodecyl-trimethylammonium, dimethyldioctadecylammonium, dioctadecyldimethylammonium, and mixtures thereof. Suitable sources of these cations of the cationic surfactant include, but are not limited to, alkyltrimethylammonium salts: such as cetyl trimethylammonium bromide (CTAB) or cetyl trimethylammonium chloride (CTAC); cetylpyridinium chloride (CPC); dimethyldioctadecylammonium chloride; dioctadecyldimethylammonium bromide (DODAB); cetyldimethylammonium acetamide bromide; or other cationic surfactant alike, including lipids. Alternatively, the surfactant may be benzyl hexadecyl dimethyl ammonium chloride (BHDC).

[0097] In one embodiment, the method includes producing one or more acid and one or more base by electrochemical decomposition of waste water. Such an embodiment is particularly useful when carbon mineralization is sought in remote locations with silica materials, industrial residues, and mine-tailings (e.g., kimberlite tailings generated during diamond mining), where lack of access to point-source emissions of carbon dioxide and processing water with low salt concentrations are otherwise barriers to deployment. In such an embodiment, carbon dioxide from air may be captured by use of regenerable, environmentally benign solvents including, for example, sodium glycinate as described herein. Carbon dioxide-loaded solvents may react to produce magnesium carbonate, while regenerating the solvent. Simultaneously, acids (e.g., HCl) and bases (e.g., NaOH, Ca(OH).sub.2, and Mg(OH).sub.2) may be electrochemically produced from brines recovered from geological carbon storage in remote locations. Acids may then, in one embodiment, be used to accelerate dissolution of magnesium silicate materials abundant in mine tailings, and the alkaline earth bases may be mineralized into Ca- and Mg-carbonates. The NaOH may, in one embodiment, be used to regenerate sodium glycinate solvents.

[0098] A second aspect relates to a method of producing one or more solid inorganic bicarbonate compound by capturing, converting, and storing carbon dioxide. The method includes providing one or more precursor compound; providing one or more carbon dioxide capture solvent or capture additive; and reacting said one or more precursor compound with said one or more carbon dioxide capture solvent or capture additive under conditions effective to produce one or more solid inorganic bicarbonate compound.

[0099] This aspect is carried out in accordance with the previously described aspect.

[0100] In one embodiment, the one or more precursor compound is a non-bicarbonate metal species.

[0101] In one embodiment, the one or more solid inorganic bicarbonate compound includes calcium bicarbonate (Ca(HCO.sub.3)), magnesium bicarbonate (Mg(HCO.sub.3).sub.2), and lithium bicarbonate (LiHCO.sub.3), sodium bicarbonate (NaHCO.sub.3), potassium bicarbonate (KHCO.sub.3), caesium bicarbonate (CsHCO.sub.3), ammonium bicarbonate (NH.sub.4HCO.sub.3), carbonic acid (H.sub.2CO.sub.3), or any combination thereof.

[0102] A third aspect relates to a system for producing one or more solid inorganic carbonate compound by capturing, converting, and storing carbon dioxide. The system includes one or more precursor compound; one or more carbon dioxide capture solvent or capture additive; and a reactor, wherein said one or more precursor compound and said one or more carbon dioxide capture solvent or capture additive react in said reactor under conditions effective to produce one or more solid inorganic carbonate compound.

[0103] This aspect is carried out in accordance with the previously described aspects.

[0104] The system described herein may, in one embodiment, include a rotating inner chamber. The system may in one embodiment include a fixed outer chamber. The rotating inner chamber and fixed outer chamber are exemplified in FIGS. 25 and 34.

[0105] In one embodiment, the reactor comprises a first inlet, and said first inlet is positioned to accept carbon dioxide loaded capture solvent or capture additive. For example, the first inlet may accept 10-50 wt % carbon dioxide loaded aqueous solvents. The aqueous solvents may be, in one example, sourced from flue gas from power plants or industrial facilities. The solvents may be regenerated in one example. The first inlet is exemplified in FIGS. 25 and 34.

[0106] In one embodiment, the reactor comprises a second inlet, and said second inlet is positioned to accept one or more precursor compound. For example, the second inlet may accept 5-50 wt % slurry of calcium- or magnesium-bearing materials in water and calcium- or magnesium-bearing solutions obtained from dissolving alkaline materials. In one embodiment, the reactor comprises an outlet, and said outlet comprises an exit stream for said one or more solid inorganic carbonate compound. The second inlet and the outlet are exemplified in FIGS. 25 and 34.

[0107] The system may include a variety of additional features to improve functionality. For example, in one embodiment, the system further includes one or more pH probe. In another embodiment, the system further includes one or more sample withdrawal port. In yet another embodiment, the system further includes one or more temperature sensor. In another embodiment, the reactor controls particle size of one or more solid inorganic carbonate compound.

[0108] A fourth aspect relates to a system for producing one or more solid inorganic bicarbonate compound by capturing, converting, and storing carbon dioxide. The system includes one or more precursor compound; one or more carbon dioxide capture solvent or capture additive; and a reactor, wherein said one or more precursor compound and said one or more carbon dioxide capture solvent or capture additive react in said reactor under conditions effective to produce one or more solid inorganic bicarbonate compound.

[0109] This aspect is carried out in accordance with the previously described aspects.

[0110] In the following description, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration specific embodiments which may be practiced. These embodiments are described in detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that structural, logical, and electrical changes may be made without departing from the scope of the present invention. The following description of example embodiments is, therefore, not to be taken in a limited sense.

[0111] The present disclosure may be further illustrated by reference to the following examples.

EXAMPLES

[0112] The following examples are intended to illustrate, but by no means are intended to limit, the scope of the present disclosure as set forth in the appended claims.

Example 1Schematic Representation of Use of Amine-Bearing Solvents to Enhance Carbon Dioxide Hydration Via the Enhanced Formation of Bicarbonate and Carbonate Species

[0113] The hypothesis is evaluated that utilizing aqueous amine-bearing solvents such as monoethanolamine (MEA) enhances CO.sub.2 hydration via the enhanced formation of bicarbonate and carbonate species in the aqueous phase at relatively low temperature and low pressure. Carbonate and bicarbonate ions then react with dissolved Ca and Mg in the aqueous phase to produce Ca- and Mg-carbonates. FIG. 1 is a schematic representation of the proposed mechanism. The integrated gas-liquid-solid reaction pathways shown in FIG. 1 represents the coupling of multiple reactions including enhanced CO.sub.2 capture and hydration using MEA solvents, mineral dissolution and carbonate precipitation. Alternatively, CO.sub.2-loaded amine-bearing solutions can be directly reacted with oxides, hydroxides or silicates of Ca and Mg in a slurry reaction environment to produce Ca- and Mg-carbonates. Both pathways involve the looping of the amine-bearing solvents from the CO.sub.2-loaded to CO.sub.2-release states by converting CO.sub.2 to Ca- and Mg-carbonates. This novel aqueous alkaline amine looping process was successfully demonstrated for the accelerated mineralization of calcium oxide and calcium chloride to produce calcium carbonate. Liu & Gadikota, Integrated CO.sub.2 Capture, Conversion, and Storage To Produce Calcium Carbonate Using an Amine Looping Strategy, Energy & Fuels 33:1722-1733 (2018); Ji et al., Integrated Absorption-Mineralisation for Low-energy CO.sub.2 Capture and Sequestration, Appl. Energy 225:356-366 (2018); and Arti et al., Single Process of CO.sub.2 Capture and Mineralization in Various Alkanolamines Using Calcium Chloride, Energy and Fuels 31:763-69 (2017), all of which are hereby incorporated by reference in their entirety. Carbonate-induced solidification of calcium silicate using MEA was extensively studied. Bobicki et al., Carbon Capture and Storage Using Alkaline Industrial Wastes, Prog. Energy Combust. Sci. 38:302-320 (2012); Li et al., A Novel Strategy for Carbon Capture and Sequestration by rHLPD Processing, Front. Energy Res. 3:53 (2016); and U.S. Patent Application Publ. No. 2011/0182799 to Riman et al., all of which are hereby incorporated by reference in their entirety.

[0114] However, the carbon mineralization of Mg-bearing oxides, hydroxides or silicates using aqueous alkaline amine looping approach has not been established. Given the abundance of Mg-bearing minerals around the world, evaluating the reactivity of Mg-bearing minerals to produce Mg-bearing carbonates using the aqueous alkaline amine looping approach needs to be explored. Shand, M. A., THE CHEMISTRY AND TECHNOLOGY OF MAGNESIA Wiley-Interscience (2006) and Falkowski et al., The Global Carbon Cycle: A Test of our Knowledge of Earth as a System, Science 290:291-296 (2000), both of which are hereby incorporated by reference in their entirety. The successful demonstration of the proposed process will allow for the unlocking of the potential of vast resources of Mg-bearing minerals for the accelerated capture, conversion and storage of CO.sub.2 in a single step. The aim of this is to explore the feasibility of using Mg-bearing materials using simple precursors such as magnesium oxide for the accelerated capture, conversion and storage of CO.sub.2 to produce magnesium carbonates. To achieve this aim, several research questions need to be addressed: (i) What is the influence of reaction temperature and MEA composition on the extent of carbon mineralization of magnesium oxide? (ii) What is the chemical composition of the carbonate-bearing materials? (3) How do the structural and morphological features of MgO dynamically evolve in these fluidic environments?

[0115] To address these research questions, laboratory-scale experiments were designed to probe the sensitivity of carbon mineralization behavior on the reaction conditions such as temperature and the composition of the MEA. This gas-liquid-solid reaction environment was designed for a constant pressure of 1 atm. The influence of aqueous phase compositions of 10-50 wt % MEA at temperatures in the range of 25 C.-90 C. on the carbon mineralization behavior of MgO was probed. A slurry composition of 15 wt % solid was held constant for all the experiments. Continuous stirring at the rate of 300 rpm5 rpm was maintained to reduce mass transfer limitations. A second of experiments were designed to probe dynamic time-resolved structural and microstructural evolution of magnesium oxide as it is reacted to produce magnesium carbonate using Ultra Small/Small/Wide Angle X-Ray Scattering (USAXS/SAXS/WAXS) measurements. Liu & Gadikota, Probing the Influence of Thermally Induced Structural Changes on the Microstructural Evolution in Shale Using Multiscale X-ray Scattering Measurements, Energy & Fuels 32:8193-8201 (2018); Liu & Gadikota, Phase Evolution and Textural Changes During the Direct Conversion and Storage of CO.sub.2 to Produce Calcium Carbonate From Calcium Hydroxide, Geosciences 8:445 (2018); Gadikota et al., In Situ Angstrom-to-Micrometer Characterization of the Structural and Microstructural Changes in Kaolinite on Heating Using Ultrasmall-Angle, Small-Angle, and Wide-Angle X-ray Scattering (USAXS/SAXS/WAXS), Ind. Eng. Chem. Res., 56:11791-11801 (2017); Ilavsky et al., Ultra-Small-Angle X-Ray Scattering at the Advanced Photon Source, J. Appl. Crystallogr. 42:469-479 (2009); Ilavsky et al., Ultra-Small-Angle X-Ray Scattering Instrument at the Advanced Photon Source: History, Recent Development, and Current Status, Metall. Mater. Trans. A Phys. Metall. Mater. Sci. 44:68-76 (2013); and Benedetti et al., Analysis of Textural Properties of CaO-Based CO.sub.2 Sorbents by Ex Situ USAXS, Chem. Eng. J. 355:760-776 (2019); and Ilavsky et al., Development of Combined Microstructure and Structure Characterization Facility for In Situ and Operando Studies at the Advanced Photon Source, J. Appl. Crystallogr. 51:867-882 (2018), all of which are hereby incorporated by reference in their entirety. Further, Grazing Incidence-Small Angle X-Ray Scattering (GI-SAXS) measurements were performed to determine the size of the nucleating magnesium carbonate particles on silica interfaces. This comprehensive research approach was used to evaluate the effectiveness of the coupled reaction pathways in directing the synthesis of magnesium carbonates in multiphase reaction environments and the underlying structural and morphological basis for the observed reactivity.

Example 2Experimental Materials and Methods for Examples 3-5

[0116] Magnesium oxide used in this integrated carbon mineralization approach with aqueous alkaline amine looping approach was procured from Sigma-Aldrich. The mean particle size, surface area, and cumulative pore volume of magnesium oxide are 8.54 m, 3.59 m.sup.2/g, and 0.0078 cm.sup.3/g, respectively. Monoethanolamine (MEA) with a purity of 98% used in these studies was procured from Alfa Aesar.

[0117] Aqueous alkaline amine looping process for accelerated carbon mineralizationThe experiments to evaluate the influence of temperature and MEA concentrations on the accelerated conversion of magnesium oxide to magnesium carbonate using the aqueous alkaline amine looping process were performed in a batch environment (Parr Reactor, Series 4590 Micro Stirred Reactor). The slurry environment comprised 17 g of liquid and 3 g of solid sample. Aqueous phase compositions comprising deionized water, 10, 30, and 50 wt % MEA were used. CO.sub.2 partial pressure of 1 atm was maintained throughout the length of the experiments. A constant stirring rate of 300 rpm5 rpm was applied. Each experiment was performed over a length of 3 hours. Extents of carbon mineralization at reaction temperatures of 25 C., 50 C., 75 C. and 90 C. were evaluated. About 5-10 minutes were needed to reach the desired reaction temperature, which marked the beginning of the experiment. All experiments were performed over 3 hours. At the end of 3 hours, vacuum filtration was used to separate the liquid contents from the solids. The recovered solid was dried in a vacuum oven for 24 hours at 90 C. to remove any residual water in the solid sample.

[0118] Characterization of chemical and morphological propertiesThe carbon mineralization efficiency using the aqueous alkaline amine looping process was evaluated based on the extent of magnesium mineralized to produce magnesium carbonate. The carbonate content used in these calculations was determined using Thermogravimetric Analyses (TGA, TGA 550, TA Instruments). TGA data provides quantitative information into the changes in the weight of the samples on heating at specific temperatures. The heating rate was set to 5 C./min from 25 C. to 800 C. and the flow rate of the N.sub.2 gas was 25 mL/min. The carbonate content in nesquehonite was determined from the weight change in the temperature range of 350 C.-450 C. Swanson et al., Directed Precipitation of Hydrated and Anhydrous Magnesium Carbonates for Carbon Storage, Phys. Chem. Chem. Phys. 42:23440-23450 (2014), which is hereby incorporated by reference in its entirety. The stoichiometric mass of MgO needed for storing a unit mass of CO.sub.2 was defined as R.sub.CO.sub.2. Gadikota et al., Experimental Design and Data Analysis for Accurate Estimation of Reaction Kinetics and Conversion for Carbon Mineralization, Ind. Eng. Chem. Res. 53:6664-6676 (2014) and Gerdemann et al., Ex Situ Aqueous Mineral Carbonation, Environ. Sci. Technol. 41:2587-2593 (2007), both of which are hereby incorporated by reference in their entirety. As reported in previous studies, the extent of carbon mineralization, Y.sub.CO.sub.2.sub.,TGA, a measure of the ratio of the amount of CO.sub.2 present in the sample with respect to the CO.sub.2 storage capacity was determined by the following relationship: Y.sub.CO.sub.2.sub.,TGA=R.sub.CO.sub.2(TGA/100TGA)100% where TGA represents the weight change that corresponds to the carbonate content in the reacted materials. To identify the species in the aqueous and solid phases, Attenuated Total Reflection-Fourier Transform Infrared spectroscopy analyses were performed (ATR-FTIR, Thermo Fisher Nicolet iS 10). The spectra were collected in the range of 6504000 cm.sup.1. The morphological features of the products were determined using Scanning Electron Microscopy (SEM, Hitachi High Technologies America, Hitachi S3400-N). The changes in the porosity and specific surface area of the powders were determined using the Brunauer-Emmett-Teller technique (BET, Quantachrome NOVAtouch Analyzer, Boynton Beach, FL).

[0119] Time-resolved structural and microstructural features as MgO is reacted in the aqueous amine looping process were determined using in-operando Ultra Small/Small/Wide Angle X-Ray Scattering (USAXS/SAXS/WAXS) measurements at Sector 9-ID at the Advanced Photon Source (APS) in Argonne National Laboratory (ANL). Liu & Gadikota, Probing the Influence of Thermally Induced Structural Changes on the Microstructural Evolution in Shale Using Multiscale X-ray Scattering Measurements, Energy & Fuels 32:8193-8201 (2018); Liu & Gadikota, Chemo-morphological Coupling During Serpentine Heat Treatment for Carbon Mineralization, Fuel 227:379-385 (2018); Gadikota et al., In Situ Angstrom-to-Micrometer Characterization of the Structural and Microstructural Changes in Kaolinite on Heating Using Ultrasmall-Angle, Small-Angle, and Wide-Angle X-ray Scattering (USAXS/SAXS/WAXS), Ind. Eng. Chem. Res., 56:11791-11801 (2017); Liu & Gadikota, Phase Evolution and Textural Changes During the Direct Conversion and Storage of CO.sub.2 to Produce Calcium Carbonate From Calcium Hydroxide, Geosciences 8:445 (2018); Ilavsky et al., Ultra-Small-Angle X-Ray Scattering at the Advanced Photon Source, J. Appl. Crystallogr. 42:469-479 (2009); Ilavsky et al., Development of Combined Microstructure and Structure Characterization Facility for In Situ and Operando Studies at the Advanced Photon Source, J. Appl. Crystallogr. 51:867-882 (2018); Gadikota et al., Towards Understanding the Microstructural and Structural Changes in Natural Hierarchical Materials for Energy Recovery: In-operando Multi-Scale X-Ray Scattering Characterization of Na- and Ca-Montmorillonite on Heating to 1150 C., Fuel 196:195-209 (2017), all of which are hereby incorporated by reference in their entirety. The arrangement comprised of a cell with a continuous flow of CO.sub.2 at the rate of 10 mL/min. In this in-situ measurement, 1 mL 30 wt % CO.sub.2-loaded MEA and 0.15 g MgO were added to an NMR tube with an internal diameter of 4 mm. CO.sub.2 was continuously supplied to the aqueous phase to ensure high concentrations of inorganic carbon in the aqueous phase. The acquisition times for USAXS, SAXS, and WAXS were 90 s, 20 s, and 30 s respectively. Silver behenate was used to calibrate SAXS and LaB6 was used to calibrate WAXS measurements. Black et al., Certification of NIST Standard Reference Material 640d, Powder Diffr. 25:187-190 (2010), which is hereby incorporated by reference in its entirety. The total X-ray flux, energy and corresponding wavelength were 10.sup.13 photon s.sup.1, 21.0 keV, and 0.59 , respectively. Irena (Ilavsky et al., Irena: Tool Suite for Modeling and Analysis of Small-Angle Scattering, J. Appl. Crystallogr. 42:347-353 (2009), which is hereby incorporated by reference in its entirety) and Nika (Ilavsky, J., Nika: Software for Two-Dimensional Data Reduction, J. Appl. Crystallogr. 45:324-326 (2012), which is hereby incorporated by reference in its entirety) software packages embedded in IgorPro (Wavemetrics, Lake Oswego, OR) were used for data analyses. Ilavsky et al., Irena: Tool Suite for Modeling and Analysis of Small-Angle Scattering, J. Appl. Crystallogr. 42:347-353 (2009) and Frykstrand et al., On the Pore Forming Mechanism of Upsalite, a Micro- and Mesoporous Magnesium Marbonate, Microporous Mesoporous Mater. 190:99-104 (2014), both of which are hereby incorporated by reference in their entirety. To capture the hierarchical morphological features during the carbonation of MgO, the combined USAXS/SAXS data were modeled using the Modeling II tool in Irena package. Ilavsky et al., Irena: Tool Suite for Modeling and Analysis of Small-Angle Scattering, J. Appl. Crystallogr. 42:347-353 (2009), which is hereby incorporated by reference in its entirety.

[0120] In-situ Grazing IncidenceSmall Angle X-Ray Scattering (GI-SAXS) measurements were performed to determine the sizes of the nucleating particles. These measurements were conducted at the beamline 12 ID-B at the Advanced Photon Source (Argonne National Laboratory, USA). A custom designed cell was used for these measurements. The internal dimensions of this cell are 10 mm10 mm15 mm. 30 wt % CO.sub.2-loaded MEA solution with a volume of 0.1988 mL was injected into 5 mL of 0.1 M Mg(NO.sub.3).sub.2 solution, which marked the beginning of the in-situ measurement. The X-ray beam was directed to the substrate with an incidence angle of .sub.i=0.11 through the two Kapton windows. This incident angle is lower than the critical angle for total reflection (.sub.c-quartz=0.14 at 14 KeV incident X-ray energy). The scattered intensity from the nucleated magnesium carbonate particles was collected using a 2-dimensional Pilatus 2 M detector (Dectris Ltd., Baden, Switzerland). The incidence X-Ray energy, a sample-to-detector distance (ds-d), and q-range for these measurements were 14 keV, 2060 mm, and 0.005 .sup.1 to 0.6 .sup., respectively. After background subtraction and 2D data reduction, the reduced data was fitted by Guinier-Porod fit.sup.60 as shown in FIG. 7C. The equations that describe the relationships of the generalized Guinier Law are listed below. Hammouda, B., A New Guinier-Porod Model, J. Appl. Crystallogr. 43:716-719 (2010), which is hereby incorporated by reference in its entirety.

[00001]$\begin{array}{cc}I\left(Q\right)=\frac{G}{Q_s}\exp \left(\frac{-Q^2{R}_g^2}{3-s}\right)\mathrm{for}Q{Q}_1& \left(\mathrm{Equation}1\right)\end{array}$$\begin{array}{cc}I\left(Q\right)=\frac{D}{Q^d}Q{Q}_1& \left(\mathrm{Equation}2\right)\end{array}$$\begin{array}{cc}{Q}_1=\frac{1}{R_g}{\left(\frac{3d}{2}\right)}^{1/2}& \left(\mathrm{Equation}3\right)\end{array}$$\begin{array}{cc}D=G\exp \left(\frac{-Q^2{R}_g^2}{3}\right)Q_1^d=G\exp \left(\frac{-d}{2}\right){\left(\frac{3d}{2}\right)}^{\frac{d}{2}}\frac{1}{R_g^d}& \left(\mathrm{Equation}4\right)\end{array}$

G and D are the Guinier and Porod scale factors. Q is the scattering variable, I(Q) is the scattered intensity, R.sub.g is the radius of gyration, d is the Porod exponent. Q.sub.1 is set up to ensure the continuity of the slopes (derivatives). A dimensionality parameter (3-s) is defined to provide more flexibility for modeling different shapes of objects. For example, objects with spherical, rod-like, and lamellae or platelet dimensions, s=0, 1; or 2, respectively. Hammouda, B., A New Guinier-Porod Model, J. Appl. Crystallogr. 43:716-719 (2010), which is hereby incorporated by reference in its entirety. The R.sub.g and Porod scale factors are calculated based on the equations represented above.

Example 3Effect of Temperature and MEA Concentration

[0121] To evaluate the influence of temperature and MEA concentration on the extent of carbon mineralization of MgO, multiphase reaction environments are constructed. The pressure of CO.sub.2 in the gas phase is held at 1 atm over the course of the experiment. The slurry was composed of 15 wt % solid. MEA compositions were evaluated as 10, 20, 30 and 50 wt % at temperatures of 25 C., 50 C., 75 C., and 90 C. Reaction times were set to 3 hours and the stirring rates at 300 rpm5 rpm. The extents of carbon mineralization of MgO as a function of MEA concentration and temperature are noted in FIG. 2 and summarized in Table 2.

TABLE-US-00002 TABLE 2 The extents of carbon mineralization of MgO as a function of MEA concentrations and temperatures. 10 wt % 20 wt % 30 wt % 50 wt % Temperature H.sub.2O MEA MEA MEA MEA 25 C. 8.1 2.1 1.6 1.5 4.2 50 C. 18.1 32.7 46.9 70.2 12.2 75 C. 42.0 46.3 52.4 62.2 52.7 90 C. 27.8 32.4 37.5 35.6 24.2
A non-linear relationship of the influence of temperature and MEA on the carbon mineralization of MgO was noted. The highest conversion of MgO to magnesium carbonate achieved with 30 wt % MEA at 50 C. is 70%. Subsequent increase in reaction temperature resulted in a lower extent of carbon mineralization. This is a result of the competing effects of temperature on CO.sub.2 absorption and carbon mineralization. Temperatures below 50 C. favor CO.sub.2 absorption in MEA.sup.61 but the kinetics of carbon mineralization are slow. Higher temperatures favor carbon mineralization but the equilibrium constant associated with CO.sub.2 uptake in MEA decreases as the reaction temperature increases. Gupta et al., Modeling Temperature Dependency of Amine Basicity Using PCM and SM8T Implicit Solvation Models, J. Phys. Chem. B. 116:1865-1875 (2012) and Kim et al, Heat of Absorption of Carbon Dioxide (CO.sub.2) in Monoethanolamine (MA) and 2-(Aminoethyl)ethanolanine (AEE A) Solutions, Ind. Eng. Chem. Res. 46:5803-5809, both of which are hereby incorporated by reference in their entirety. As a result, there is a non-monotonic dependence in the combined absorption-mineralization behavior of MgO with temperature.

[0122] At similar experimental conditions, 100% conversion of CaO to calcium carbonate was reported. Liu & Gadikota, Integrated CO.sub.2 Capture, Conversion, and Storage To Produce Calcium Carbonate Using an Amine Looping Strategy, Energy & Fuels 33:1722-1733 (2018), which is hereby incorporated by reference in its entirety. As MEA concentrations are increased starting from DI water to 10 wt % and 20 wt % MEA, high conversions of MgO to magnesium carbonate are achieved at 75 C. At 30 wt % MEA, higher extents of carbon mineralization were achieved at 50 C. At 50 wt % MEA, gel formation was noted with MgO which made it challenging to separate the solid and liquid constituents. The hypothesis is that the enhanced hydrogen bonding resulting from the interactions between the dissolved fluidic constituents result in gel formation. This observation is consistent with the formation of magnesium carbonate-based porous gels. Frykstrand et al., On the Pore Forming Mechanism of Upsalite, a Micro- and Mesoporous Magnesium Marbonate, Microporous Mesoporous Mater. 190:99-104 (2014), which is hereby incorporated by reference in its entirety. The hypothesis for the limited reactivity of MgO at high concentrations of MEA, i.e., 50 wt % emerges from the mass transfer limitations caused by gel formation.

[0123] To identify the constituents in the solid phase and aqueous phase, ATR-FTIR analyses were performed. A wide range of phases were identified. Absorption bands at 1471 cm.sup.1 and 1515 cm.sup.1 indicates 3 asymmetric CO.sub.3.sup.2 stretching mode, which matches with features of nesquehonite (MgCO.sub.3.Math.3H.sub.2O), and lansfordite (MgCO.sub.3.Math.5H.sub.2O). Morgan et al., Increased Thermal Stability of Nesquehonite (MgCO.sub.3.Math.3H.sub.2O) in the Presence of Humidity and CO.sub.2: Implications for Low-Temperature CO.sub.2 Storage, Int. J. Greenh. Gas Control 39:366-376 (2015); Yin et al., Synthesis and Formation Mechanism of Micro/nano Flower-like MgCO.sub.3.Math.5H.sub.2O, Int. J. Minerals Metallurgy Mater. 21:304-310 (2014); and Hopkinson et al., Phase Transitions in the System MgOCO.sub.2H.sub.2O During CO.sub.2 Degassing of Mg-Bearing Solutions, Geochim. Cosmochim. Acta 76:1-13 (2012), all of which are hereby incorporated by reference in their entirety. The bands at 1097 cm.sup.1 and 852 cm.sup.1 reflect the 1 symmetric CO, and the 2 CO non-planar bending vibrations, respectively. These observations are consistent with previous studies that show the formation of hydrated magnesium carbonates at the experimental conditions of interest (FIGS. 3A and 8). Analyses of the liquid recovered post-reaction at 30 wt % MEA and 50 C. showed that MEAH.sup.+, MEACOO.sup., and CO.sub.3.sup.2 ions are the dominant species present in the aqueous phase (FIGS. 3B and 9). At lower MEA concentrations of 10 wt % and 20 wt %, the relative intensities of these liquid species, in particular carbonate species is lower compared to that at 30 wt % MEA. The aqueous species are identified using FT-IR analyses in this with MgO as the reactant are consistent with the observations reported by others with CaO as the reactant. Ji et al., Integrated Absorption-Mineralisation for Low-energy CO.sub.2 Capture and Sequestration, Appl. Energy 225:356-366 (2018), which is hereby incorporated by reference in its entirety. The CO.sub.2 uptake and release behavior of MEA is evident from the multiple MEA species detected in the ATR FT-IR spectra.

Example 4Morphological Characterization of Magnesium Carbonates

[0124] The morphological features before and after reacting CO.sub.2 with MgO were determined using scanning electron microscopy images. The sizes of the unreacted MgO grains is to the order of a few micrometers (FIG. 4A). Needle-shaped nesquehonite (MgCO.sub.3.Math.3H.sub.2O) is dominant after MgO is reacted with 30 wt % MEA at 50 C. in pCO.sub.2=1 atm (FIG. 4B). Further, in-operando Ultra Small and Small Angle X-Ray Scattering (USAXS/SAXS) measurements were performed to determine the dynamic evolution in the structural and morphological features as MgO is reacted with CO.sub.2-loaded MEA (FIG. 5A). The experimental conditions at which these measurements were performed are 25 C., 1 atm, and CO.sub.2-loaded MEA concentrations of 30 wt %. These time-resolved measurements show the emergence of carbonate phases in the high q regimes that corresponds to the SAXS regime. The peaks at q1.02 .sup.1 and q0.51 .sup.1 correspond to the (0 0 2) and (0 0 1) reflections of lansfordite (MgCO.sub.3.Math.5H.sub.2O). Giester et al., The Crystal Structure of Nesquehonite, MgCO.sub.3.Math.3H.sub.2O, From Lavrion Greece, Mineral. Petrol. 70:153-163 (2000) and Ming et al., Synthesis and Characterization of Lansfordite and Nesquehonite, Soil Sci. Soc. Am. J. 49:1303-1308 (2010), both of which are hereby incorporated by reference in their entirety. These data suggest that lansfordite growth is a precursor to the formation of nesquehonite. In hydrothermal environments where the effects of temperature and MEA compositions on the accelerated carbon mineralization of MgO to magnesium carbonate are evaluated as shown in FIG. 2, it is hypothesized that lansfordite undergoes pseudomorphic transformations to produce nesquehonite.

[0125] Since the characteristic peak for (001) plane of lansfordite (MgCO.sub.3.Math.5H.sub.2O) emerged after 89 min of reaction time, the data were modeled in two stages. Morgan et al., Increased Thermal Stability of Nesquehonite (MgCO.sub.3.Math.3H.sub.2O) in the Presence of Humidity and CO.sub.2: Implications for Low-Temperature CO.sub.2 Storage, Int. J. Greenh. Gas Control 39:366-376 (2015); Yin et al., Synthesis and Formation Mechanism of Micro/nano Flower-like MgCO.sub.3.Math.5H.sub.2O, Int. J. Minerals Metallurgy Mater. 21:304-310 (2014); and Hopkinson et al., Phase Transitions in the System MgOCO.sub.2H.sub.2O During CO.sub.2 Degassing of Mg-Bearing Solutions, Geochim. Cosmochim. Acta 76:1-13 (2012), all of which are hereby incorporated by reference in their entirety. In the first stage, the USAXS/SAXS curves were modeled using two unified fit levels in two different q regions, where q=(4/)sin(/2) and is the wavelength of incident X-ray and is the scattering angle. The two q-regions 0.001-0.02 .sup.1 and 0.02-0.8 .sup.1, were modeled based on the approach proposed by Beaucage. Beaucage, Approximations Leading to a Unified Exponential/Power-law Approach to Small-angle Scattering, J. Appl. Crystallogr. 28:717-728 (1995) and Giester et al., The Crystal Structure of Nesquehonite, MgCO.sub.3.Math.3H.sub.2O, From Lavrion, Greece, Mineral. Petrol. 70:153-163 (2000), both of which are hereby incorporated by reference in their entirety. The fit in each level can be described by a Guinier regime and a power-law regime. Typically, the model assumes a spherical and centrosymmetric shape of the scattering objects. However, it can be applied to a broad range of scatterer shapes, including spheres, rods, lamellae, cylinders etc. based on its formulation in terms of radius of gyration (R.sub.g) and free power-law slope. In the second stage of fitting, for all the data curves after 89 min, the scattering profiles were fitted using three levels of fits. Like the approach in first stage, two regions of unified fit were modeled in q ranges of 0.001-0.02 .sup.1 and 0.02-0.3 .sup.1, respectively. Additionally, a Lorentzian diffraction peak was fitted in the q range of 0.3-0.8 .sup.1. The representative model fits overlaid on experimental data are shown in FIG. 13. The normalized integrated intensity of (001) peak of lansfordite is presented in FIG. 5B. Morgan et al., Increased Thermal Stability of Nesquehonite (MgCO.sub.3.Math.3H.sub.2O) in the Presence of Humidity and CO.sub.2: Implications for Low-Temperature CO.sub.2 Storage, Int. J. Greenh. Gas Control 39:366-376 (2015); Yin et al., Synthesis and Formation Mechanism of Micro/nano Flower-like MgCO.sub.3.Math.5H.sub.2O, Int. J. Minerals Metallurgy Mater. 21:304-310 (2014); and Hopkinson et al., Phase Transitions in the System MgOCO.sub.2H.sub.2O During CO.sub.2 Degassing of Mg-Bearing Solutions, Geochim. Cosmochim. Acta 76:1-13 (2012), all of which are hereby incorporated by reference in their entirety. Additionally, the modeling results from the unified fit in q range of 0.02-0.8 .sup.1, were of interest and are discussed further. The power-law slope and radius of gyration (R.sub.g) obtained from the unified fit are presented in FIG. 6A. The R.sub.g values are representative of pore dimensions.

[0126] The evolution in the pore morphology as MgO is converted to MgCO.sub.3 is determined by tracking changes in the characteristic radius of gyration, R.sub.g. Initially, an R.sub.g value of 5 nm was noted for the precursor, MgO. This value is comparable to the representative pore size determined from N.sub.2 BET adsorption measurements (FIG. 6B). The increase in R.sub.g values noted until 61 minutes of reaction time, is attributed to the dissolution of MgO. As discussed earlier, the (001) peak for lansfordite first emerged after 89 minutes of reaction time (FIG. 5B), the R.sub.g values started to decrease and achieved a value of 3.4 nm as the carbonation of MgO began. The changes in the R.sub.g values corresponding to the phase change of MgO to MgCO.sub.3 during reaction are mapped in (FIG. 6C). These values of R.sub.g remained persistent till the end of reaction (385 minutes). For comparison, the pore dimensions of MgCO.sub.3 powder obtained after reaction of MgO with 30 wt. % MEA in a batch reactor for 3 hours was compared with the R.sub.g value at 183 minutes. The N.sub.2 BET data determined at these experimental conditions and shown in FIG. 6D) is mapped to FIG. 6A). The Rg values determined from USAXS/SAXS measurements are comparable to the pore radius data determined from N.sub.2 BET measurements. The reduction in the pore radius as carbon mineralization occurs suggests that the diffusion limitations may contribute to the changes in reactivity.

[0127] Insights into the evolution of pore-solid interfaces can be obtained from the porod exponent. Porod exponent between 2 and 3 represents scattering from branched networks or mass fractals. Porod exponents between 2.2-2.8 are noted prior to the development of the lansfordite phase. Concurrent dissolution of MgO and lansfordite phase growth result in Porod slopes in the range of 1.6-2.4. These data show that the fractal character of the pore-solid interfaces evolves as MgO reacts to produce MgCO.sub.3. While USAXS/SAXS measurements provide insights into the influence of bulk morphological changes and structural evolution during the carbon mineralization of magnesium oxide, it is challenging to determine the sizes of the magnesium carbonate particles in the proposed process. The research question in this context is as follows: How can the sizes of the carbonate particles once the Mg cations are mobilized in the aqueous phase be determined? To address this research question, in-operando Grazing Incidence-Small Angle X-Ray Scattering (GI-SAXS) measurements to determine the sizes of the magnesium carbonate particles is used. FIG. 7A is a schematic of the GI-SAXS cell. 0.1988 mL of 30 wt % CO.sub.2-loaded MEA solution was injected into 5 mL 0.1 M Mg(NO.sub.3).sub.2 solution. The reaction vessel used in these experiments was made from silica. To mimic the formation of magnesium carbonate particles on these silica surfaces, solid quartz substrate (100) was used. These quartz surfaces were rinsed with acetone to remove any organic contaminants. Fernandez-Martinez et al., In Situ Determination of Interfacial Energies between Heterogeneously Nucleated CaCO.sub.3 and Quartz Substrates: Thermodynamics of CO.sub.2 Mineral Trapping, Environ. Sci. Technol. 47:102-109 (2013), which is hereby incorporated by reference in its entirety. FIG. 7B is an example of raw 2D GISAXS scattering pattern from quartz (100) substrates with MgO. The original image is shown, without background subtraction and further processing. After background subtraction and 2D data reduction, the reduced data was fitted by Guinier-Porod fit (Hammouda, B., A New Guinier-Porod Model, J. Appl. Crystallogr. 43:716-719 (2010), which is hereby incorporated by reference in its entirety) as shown in FIG. 7C.

[0128] The formation of magnesium carbonate particles was noted after about 60 minutes. The scattering curves were obtained by reducing the data contained in the 2-D images. Fernandez-Martinez et al., In Situ Determination of Interfacial Energies between Heterogeneously Nucleated CaCO.sub.3 and Quartz Substrates: Thermodynamics of CO.sub.2 Mineral Trapping, Environ. Sci. Technol. 47:102-109 (2013), which is hereby incorporated by reference in its entirety. The sizes of the particles are obtained by fitting the Guinier-Porod fit based on Equations 1-4. Hammouda, B., A New Guinier-Porod Model, J. Appl. Crystallogr. 43:716-719 (2010), which is hereby incorporated by reference in its entirety. Also, the factor s was set as 1 based on the formation of rod-like shape particles observed in the SEM images in FIG. 4B. The size distribution in FIG. 7D was extrapolated from the FIG. 7C based on the maximum entropy method using Irena and Nika packages. From these data, the sizes of the precipitates are inferred to the order of 15-16 nm (FIG. 7D). At these experimental conditions, the formation of hydrated magnesium carbonates is expected. Fernandez-Martinez et al., In Situ Determination of Interfacial Energies between Heterogeneously Nucleated CaCO.sub.3 and Quartz Substrates: Thermodynamics of CO.sub.2 Mineral Trapping, Environ. Sci. Technol. 47:102-109 (2013), which is hereby incorporated by reference in its entirety. In comparison, the sizes of the calcium carbonate is approximately 2 nm. Fernandez-Martinez et al., in Situ Determination of Interfacial Energies between Heterogeneously Nucleated CaCO.sub.3 and Quartz Substrates: Thermodynamics of CO.sub.2 Mineral Trapping, Environ. Sci. Technol. 47:102-109 (2013) and Radha et al., Energetic and Structural Studies of Amorphous Ca1-xMgxCO.sub.3.Math.nH.sub.2O (0x1), Geochim. Cosmochim. Acta 90:83-95 (2012), both of which are hereby incorporated by reference in their entirety. These GI-SAXS data provide insights into the size of the magnesium carbonate particles on silica surfaces, while the USAXS/SAXS data show the emergence of metastable lansfordite and the characteristic pore size as MgO is converted to metastable magnesium carbonate phases.

Example 5Discussion of Examples 1-4

[0129] In the above examples, the effectiveness of utilizing aqueous alkaline amine looping process for the directed synthesis of magnesium carbonate starting from magnesium oxide as the precursor is examined. Experiments were performed in a multiphase reaction environment comprising CO.sub.2 at a pressure of 1 atm with temperature varying between 25 C. to 90 C., and aqueous concentrations of MEA varying from 0 to 50 wt %. The maximum extent of carbon mineralization achieved with magnesium oxide was 70% in 30 wt % MEA solution at 50 C. for a reaction time of 3 hours. The formation of hydrated phases of magnesium carbonate such as nesquehonite (MgCO.sub.3.Math.3H.sub.2O) was noted. Small angle X-ray scattering measurements showed the formation of lansfordite at system conditions as likely precursors prior to the formation of nesquehonite. The high carbonate conversions achieved with the use of magnesium oxide using the aqueous alkaline amine looping demonstrate the effectiveness of using the proposed approach for the direct capture, conversion and storage of CO.sub.2 or can be adapted for the reactive separation of CO.sub.2. In the context of Carbon Capture and Storage (CCS) or more broadly processes needed for decarbonization or carbon removal, a single integrated process is presented that combines CO.sub.2 capture and storage as Mg-bearing carbonates. The end-product of this process which is magnesium carbonate produced from anthropogenic CO.sub.2 can be utilized in filler materials. The high extents of carbon mineralization with MgO at significantly lower temperatures of 50 C. demonstrate that the proposed reaction pathways are promising alternatives to the high pressure and high temperature routes or chemically intensive routes for carbon mineralization previously reported in literature. Having demonstrated the feasibility of these chemical pathways with pure precursor MgO, subsequent research efforts will be directed towards exploring the use of alkaline industrial residues with high Ca and Mg content and naturally occurring Ca- and Mg-bearing silicate minerals for the low temperature and integrated capture, conversion and storage of CO.sub.2 as Ca- and Mg-bearing carbonates.

Example 6Experimental Materials and Methods for Examples 7-8

[0130] The alkaline precursors used in the present disclosure calcium oxide (CaO) and calcium silicate (CaSiO.sub.3) were procured from Sigma-Aldrich. Glycine was purchased from Alfa Aesar with 99% purity. Sodium hydroxide was procured from Fisher Scientific. Na-glycinate solutions with varying concentrations was prepared by combining pre-determined concentrations of NaOH with glycine and stirring at 500 rpm for 60 minutes. The reaction associated with producing Na-glycinate is as follows: CH.sub.2COOHNH.sub.2+NaOH.Math.CH.sub.2COOHNH.sup.+Na.sup.++H.sub.2O. As noted in this reaction, the stoichiometric ratio of NaOH and glycine is 1:1. Hu et al., Carbon Dioxide Capture by Solvent Absorption Using Amino Acids: A Review, Chinese J. Chem. Eng. 26:2229-2237 (2018), which is hereby incorporated by reference in its entirety.

[0131] Aqueous alkaline amino acid looping process for accelerated carbon mineralizationThe experiments were performed in the Parr Reactor (Series 4590 Micro Stirred Reactor). The solid to liquid ratio is maintained at 3:17 by weight for all the experiments. Experiments were performed in water and Na-glycinate concentrations of 0.5 M and 1.0 M. The reactor was purged with pure CO.sub.2 for 1 min to remove air from the headspace. CO.sub.2 partial pressure was maintained at 1 atm for all the experiments. A stirring rate of 300 rpm5 rpm was held constant for all the experiments. The experiments were performed for 1 hour, 3 hours, and 5 hours. Reaction temperatures of 25 C., 50 C., 75 C. and 90 C. were studied. At the end of the experiment, the liquid and solid contents were separated using vacuum filtration. Residual water in the solid samples was removed by drying in a vacuum oven for 12 hours at 90 C. A schematic of the experimental setup is shown in FIG. 21.

[0132] Quantification of Carbonate Formation and the Corresponding Morphological FeaturesThe effectiveness of Na-glycinate in enabling the mineralization of CO.sub.2 was determined using the extent of carbon mineralized. The carbonate content was determined using Thermogravimetric Analyses (SDT, TA Instruments, SDT 650). The heating rate was set to 5 C./min, with starting and ending temperatures of 25 C. and 800 C., respectively. The flow rate of the N.sub.2 gas in the TGA balance was set to 10 mL/min. The carbonate content in the recovered samples was determined based on the change in the weight of the samples. Calcium carbonate decomposition to produce CaO and CO.sub.2 occurs in the temperature range of 600-800 C. Li et al., Decomposition Kinetic Characterists of Calcium Carbonate Containing Organic Acids by TGA, Arab. J. Chem. 10:52534-52538 (2017), which is hereby incorporated by reference in its entirety. The following relationship was used to determine the extent of carbon mineralized, where TGA represents the weight change that corresponds to the carbonate content in the reacted materials and R.sub.CO.sub.2 represents to the amount of the mineral needed to store a unit mass of CO.sub.2. Gadikota et al., Experimental Design and Data Analysis for Accurate Estimation of Reaction Kinetics and Conversion for Carbon Mineralization, Ind. Eng. Chem. Res. 53:6664-6676 (2014) and O'Connor et al., Aqueous Mineral Carbonation: Mineral Availability, Pretreatment, Reaction Parametrics, and Process Studies, Final Report DOE/ARC-TR-004-002 (2004), both of which are hereby incorporated by reference in their entirety.

[00002]$Y_{{\mathrm{CO}}_2,\mathrm{TGA}}=R_{{\mathrm{CO}}_2}\left(\frac{\mathrm{TGA}}{100-\mathrm{TGA}}\right)100\%$

[0133] The changes in the functional groups were identified based on the infrared absorption spectra determined using Attenuated Total Reflection-Fourier Transform Infrared spectroscopy analyses (ATR-FTIR, Thermo Fisher Nicolet iS50) in the range of 3004000 cm.sup.1. The morphological features of the products were determined using Scanning Electron Microscopy (SEM, LEO 1550 FESEM). The crystalline features were determined using Wide Angle X-Ray Scattering (WAXS) measurements were performed at Sector 9-ID at the Advanced Photon Source (APS) in Argonne National Laboratory (ANL). Liu et al., Probing the Influence of Thermally Induced Structural Changes on the Microstructural Evolution in Shale using Multiscale X-ray Scattering Measurements, Energy & Fuels 32:8193-8201 (2018); Liu et al., Phase Evolution and Textural Changes during the Direct Conversion and Storage of CO.sub.2 to Produce Calcium Carbonate from Calcium Hydroxide, Geosciences 8:445 (2018); Liu et al., Chemo-morphological Coupling During Serpentine Heat Treatment for Carbon Mineralization, Fuel 227:379-385 (2018); Ilvasky et al., Ultra-small-angle X-ray scattering at the Advanced Photon Source, J. Appl. Cryst. 42:469-479 (2009); Ilvask et al, Development of Combines Microstructure and Structure Characterization Facility for In Situ and Operando Studies at the Advances Photon Source, J. Appl. Cryst. 51:867-882 (2018); Gadikota et al., In Situ Angstrom-to-Micrometer Characterization of the Structural and Microstructural Changes in Kaolinite on Heating Using Ultrasmall-Angle, Small-Angle, and Wide-Angle X-ray Scattering (USAXS/SAXS/WAXS), Ind. Eng. Chem. Res. 56:11791-11801 (2017); and Gadikota et al, Towards Understanding the Microstructural and Structural Changes in Natural Hierarchical Materials for Energy Recovery: In-operando Multi-Scale X-ray Scattering Characterization of Na- and Ca-montmorillonite on heating to 1150 C., Fuel 196:195-209 (2017), all of which are hereby incorporated by reference in their entirety. The total X-ray flux, energy and corresponding wavelength were 10.sup.13 photon s.sup.1, 21.0 keV, and 0.59 , respectively. The WAXS measurements were calibrated using LaB6 (Black et al., Certification of NIST Standard Reference Material 640d, Powder Diffr. 25:187-190 (2010), which is hereby incorporated by reference in its entirety), and the acquisition time for each measurement was set to 30 seconds. Data reduction and analyses were performed using the Nika (Ilvasky et al., Nika: Software for Two-Dimensional Data Reduction, J. Appl. Cryst. 45:324-328 (2012), which is hereby incorporated by reference in its entirety) software packages embedded in IgorPro (Wavemetrics, Lake Oswego, OR). Ilvasky et al., Irena: Tool Suite for Modeling and Analysis of Small-Angle Scattering, J. Appl. Cryst. 42:347-353 (2009) and Ilvasky et al., Nika: Software for Two-Dimensional Data Reduction, J. Appl. Cryst. 45:324-328 (2012), both of which are hereby incorporated by reference in their entirety. X-Ray Diffraction (XRD) analyses was performed using the Bruker D8 Advance ECO powder diffractometer. The acquisition times for each data point is 0.1 s, and the increment of the time step is 0.0195.

Example 7Results of Example 6

[0134] The experiments in the present disclosure are designed to evaluate the hypothesis that Na-glycinate is an effective CO.sub.2 capture and transfer agent for the accelerated carbon mineralization. CO.sub.2 capture using Na-glycinate proceeds via a zwitterionic mechanism to release bicarbonate ions into the aqueous phase. Rochelle, Amine Scrubbing for CO.sub.2 Capture, Science 325:1652-1654 (2009), which is hereby incorporated by reference in its entirety. Bicarbonate ions can dissociate to produce carbonate ions at high pH conditions, which aids carbon mineralization. Hydroxyl ions aid the regeneration of the sodium glycinate (FIG. 14). To probe the speciation behavior of Na-glycinate as it reacts with water, in-situ FT-IR measurements are performed. The carbon mineralization behavior of Na-glycinate with CaO and CaSiO.sub.3 and the morphological features of the carbonate-bearing end materials are discussed in following sections.

[0135] CO.sub.2 reaction with sodium glycinateTo determine the dynamic changes in the functional groups as CO.sub.2 is captured using Na-glycinate, in-situ ATR FT-IR analyses were performed. 1 mL 1 M Na-glycinate is loaded into the cell and CO.sub.2 at a pressure of 1 atm is supplied to this cell. CO.sub.2 reacts with glycinate to generate the corresponding carbamic acid, followed by deprotonation by a second equivalent of glycine to produce carbamate and zwitterionic glycine (Reaction 1). Brethom et al., Direct Air Capture of CO.sub.2 via Aqueous-Phase Absorption and Crystalline-phase Release Using Concentrated Solar Power, Nat. Energy 3:553-559 (2018); Custelcean et al., Direct Air Capture of CO.sub.2 with Aqueous Amino Acids and Solid Bis-Iminoguanidines (BIGs), Ind. Eng. Chem. Res. 58:23338-23346 (2019); Hu et al., Carbon Dioxide Capture by Solvent Absorption Using Amino Acids: A Review, Chinese J. Chem. Eng. 26:2229-2237 (2018); Guo et al., Amino Acids as Carbon Capture Solvents: Chemical Kinetics and Mechanism of the Glycine+CO.sub.2 Reaction, Energy & Fuels 27:3898-3904 (2013); Zhang et al., Absorption of CO.sub.2 by Amino Acid-Functionalized and Traditional Dicationic Ionic Liquids: Properties, Henry's Law Constants and Mechanisms, Chem. Eng. J. 214:355-363 (2013), which is hereby incorporated by reference in their entirety. Hydrolysis of the carbamate results in glycinate and bicarbonate ions (Reaction 2).

##STR00001## ##STR00002## ##STR00003##

[0136] Table 3 summarizes the band assignments of species. As CO.sub.2 is captured by Na-glycinate, the peak that corresponds to the asymmetric stretching vibration of CO at 1395 cm.sup.1 in CO.sub.3.sup.2 ions increases rapidly from the start of the experiment to the first 90 minutes, and the peak increase slows from 90 min to 180 min. Davis et al., A Vibrational-Spectroscopic Study of the Species Present in the CO.sub.2H.sub.2O System, J. Solution Chem. 1:329-339 (1972), which is hereby incorporated by reference in its entirety. This tendency is similar to the stretching modes in CN and bending mode of NH at 1120 cm.sup.1, 1413 cm.sup.1 and 1545 cm.sup.1 corresponding to the formation of NH.sub.2COO.sup. species. Milella et al., Estimating Speciation of Aqueous Ammonia Solutions of Ammonium Bicarbonate: Application of Least Squares Methods to Infrared Spectra, React. Chem. Eng. 4:1284-1302 (2019), which is hereby incorporated by reference in its entirety. The area under the peaks of these representative peaks is integrated and normalized to determine the temporal evolution of the species. Further the evolution in the bicarbonate peaks that correspond to the (COH) vibrations of the COH group and (CO) vibrations of the CO group are consistent with Reaction 2 in which the hydrolysis of the carbamate ions results in the formation of glycinate and bicarbonate ions (Reaction 2). The availability of bicarbonate ions during the capture of CO.sub.2 using Na-glycinate motivate the combination of this pathway with carbon mineralization of CaO and CaSiO.sub.3.

TABLE-US-00003 TABLE 3 Main infrared band assignments of the species present in the CO.sub.2Na-glycinate-H.sub.2O system. The symbols , .sub.a and indicate the stretching mode, the asymmetric stretching mode, and the bending mode of the relevant molecules, respectively. Species Band Position (cm.sup.1) Assignment Reference NH.sub.2COO.sup. 1120 (CN) [75, 86, 87] 1413 (CN) [75, 88] 1545 (NH) [75, 86] HCO.sub.3.sup. 1105 .sub.a(COH) [75] 1300 (COH) [75] 1365 (CO) [75] CO.sub.3.sup.2 1395 .sub.a(CO) [74]
Davis et al., A Vibrational-Spectroscopic Study of the Species Present in the CO.sub.2H.sub.2O System, J. Solution Chem. 1:329-339 (1972); Milella et al., Estimating Speciation of Aqueous Ammonia Solutions of Ammonium Bicarbonate: Application of Least Squares Methods to Infrared Spectra, React. Chem. Eng. 4:1284-1302 (2019); Pretsch et al., Structure Determination of Organic Compounds, Berlin: Springer-Verlag 108 (2000); and Hisatsune, Low-temperature Infrared Study of Ammonium Carbamate Formation, Can. J. Chem. 62:945-948 (1984); and Frasco, Infrared Spectra of Ammonium Carbamate and Deuteroammonium Carbamate, J. Chem. Phys. 41:2134 (1964), all of which are hereby incorporated by reference in their entirety.

[0137] Effect of temperatureIn these carbon mineralization experiments, the hypothesis that there is a non-monotonic temperature dependence on the carbon mineralization behavior of CaO and CaSiO.sub.3 in the single step capture and carbonate mineralization approach is explored. CO.sub.2 capture by aqueous solvents is generally favored below 40 C., while regeneration is favored at higher temperatures. Brethom et al., Direct Air Capture of CO.sub.2 via Aqueous-Phase Absorption and Crystalline-phase Release Using Concentrated Solar Power, Nat. Energy 3:553-559 (2018); Garrabrant et al., Energy-Efficient CO.sub.2 Capture from Flue Gas by Absorption with Amino Acids and Crystallization with a Bis-Iminoguanidine, Ind. Eng. Chem. Res. 58:10510-10515 (2019); and Hu et al., Carbon Dioxide Capture by Solvent Absorption Using Amino Acids: A Review, Chinese J. Chem. Eng. 26:2229-2237 (2018), all of which are hereby incorporated by reference in their entirety. However, higher temperatures favor the dissolution of CaO and CaSiO.sub.3 and the precipitation of calcium carbonates. Gadikota, Commentary: Ex Situ Aqueous Mineral Carbonation, Front. Energy Res. 4:21 (2016); Gerdemann et al., Ex Situ Aqueous Mineral Carbonation, Enviorn. Sci. Technol. 41:2587-2593 (2007); and Gerdemann et al., Ex-Situ and In-Situ Mineral Carbonation as a Means to Sequester Carbon Dioxide, DOE/ARC-2004-031 (2004), all of which are hereby incorporated by reference in their entirety. To investigate the influence of temperature on the overall kinetics of CO.sub.2 capture and mineralization, experiments were performed at 25 C., 50 C., 75 C., and 90 C. in 1.0 M Na-glycinate for a reaction time of 3 hours with 15 wt % solid and a stirring rate of 300 rpm.

[0138] The extents of carbon mineralization of CaO at 25 C., 50 C., 75 C., and 90 C. are 77.0%, 95.1%, 94.2%, and 97%, respectively. The extents of carbon mineralization of CaSiO.sub.3 at 25 C., 50 C., 75 C., and 90 C. are 6.6%, 16.6%, 31.0%, and 27.9%, respectively. These data show that near complete conversion of CaO to CaCO.sub.3 can be achieved at temperatures in the range of 50-90 C. However, the conversion of CaSiO.sub.3 to CaCO.sub.3 does not exceed 31.0% in this temperature range. These data are consistent with prior published work using MEA as the solvent. Liu et al., Integrated CO.sub.2 Capture, Conversion, and Storage To Produce Calcium Carbonate Using an Amine Looping Strategy, Energy & Fuels 33:1722-1733 (2018), which is hereby incorporated by reference in its entirety. The highest reported conversion of CaSiO.sub.3 to CaCO.sub.3 was 36% with 50 wt % MEA. Lower extents of carbon mineralization with CaSiO.sub.3 compared to CaO are attributed to slower dissolution rates and the formation of mass transfer limiting silica passivation layers. Daval et al., The Effect of Silica Coatings on the Weathering Rates of Wollastonite (CaSiO3) and Forsterite (Mg2SiO4): An Apparent Paradox?, Water-Rock Interact. 713-717 (2010) and Daval et al., Linking m-scale Measurements of the Anisotropy of Silicate Surface Reactivity to Macroscopic Dissolution Rate Laws: New Insights Based on Diopside, Geochim. Cosmochim. Acta 107:121-134 (2013), both of which are hereby incorporated by reference in their entirety.

[0139] The effect of competing reactions is more clearly delineated in the case of CaSiO.sub.3 where complete conversion to CaSiO.sub.3 is not achieved. One of the key considerations is the change in the reaction rate of CO.sub.2 captured using glycinate as a function of temperature. Guo and co-workers showed that the rate constant of the glycine anion NH.sub.2CH.sub.2CO.sub.2.sup. reacting with CO.sub.2 is represented by the following expression (Guo et al., Amino Acids as Carbon Capture Solvents: Chemical Kinetics and Mechanism of the Glycine+CO.sub.2 Reaction, Energy & Fuels 27:3898-3904 (2013), which is hereby incorporated by reference in its entirety):

[00003]$k\left(M^{-1}{s}^{-1}\right)=1.24{10}^{12}\exp \left[-\frac{5459}{T\left(K\right)}\right]$

[0140] The rate constants for the reaction between CO.sub.2 and NH.sub.2CH.sub.2CO.sub.2.sup. at 25 C., 50 C., 75 C., and 90 C. are 1.3710.sup.4 M.sup.1s.sup.1, 5.6710.sup.4 M.sup.1s.sup.1, 1.9110.sup.5 M.sup.1s.sup.1, and 3.6510.sup.5 M.sup.1s.sup.1, respectively. Guo et al., Amino Acids as Carbon Capture Solvents: Chemical Kinetics and Mechanism of the Glycine+CO.sub.2 Reaction, Energy & Fuels 27:3898-3904 (2013), which is hereby incorporated by reference in its entirety. However, the highest extents of carbon mineralization of CaSiO.sub.3 are noted at 75 C. as opposed to 90 C. The higher dissolution rates of CaSiO.sub.3 and the decreasing solubility of CaCO.sub.3 with increasing temperature favor carbonate formation at 75 C. as opposed to lower temperatures of 25 C. Palandri et al., A Compilation of Rate Parameters of Water-Mineral Interaction Kinetics for Application to Geochemical Modeling, U.S. Geological Survey (2004) and Weyl et al, The Change in Solubility of Calcium Carbonate with Temperature and Carbon Dioxide Content, Geochim. Cosmochim. Acta 17:214-225 (1959), both of which are hereby incorporated by reference in their entirety. FTIR analysis of the aqueous phase showed that the intensity of NH peak corresponding to NH.sub.2COO.sup. species at 1545 cm.sup.1 in unreacted 1 M Na-glycinate progressively decreases with increase in temperature in the case of CaO (FIG. 17A) and CaSiO.sub.3 (FIGS. 18A-18C). The reduced concentration of COO.sup. peak corresponding to the bicarbonate species in the fluids recovered post-reaction is consistent with the uptake of CO.sub.2 from the aqueous phase to produce calcium carbonates.

[0141] Effect of amino acid salt concentrationTo evaluate if carbon mineralization is limited by the concentration of the CO.sub.2 capture solvent, concentrations of 0, 0.5 M, 1.0 M, and 3.0 M Na-glycinate at 75 C. for 3 hours with 15 wt % solid and a stirring rate of 300 rpm is investigated. The extents of carbon mineralization with CaO at 0, 0.5 M, 1.0 M, and 3.0 M Na-glycinate are 42.6%, 68.4%, 94.2%, and 92.1%, respectively. The extents of carbon mineralization with CaSiO.sub.3 at 0, 0.5 M, 1.0 M, and 3.0 M Na-glycinate are 16.7%, 14.1%, 31.0%, and 23.6%, respectively. In the case of CaSiO.sub.3 and CaO, the highest extents of carbon mineralization are achieved at 75 C. FT-IR analyses of the liquid effluents showed that the COO.sup. peak at a wavelength of 1595 cm.sup.1 is prominent in the effluent associated with the 3 M Na-glycinate case compared to concentrations at 0.5 M and 1.0 M (FIGS. 18A-18C). These data suggest that carbon mineralization at elevated concentrations of Na-glycinate is not limited by the availability of carbonate or bicarbonate ions. However, in the case of CaSiO.sub.3, COO.sup. peak is not prominent, suggested that the carbonate-bearing species are consumed. It is also interesting to note that the OH peak in the FT-IR data (FIGS. 17A-17C and FIGS. 18A-18C) increases with the concentration of Na-glycinate. This is because the pH of the sodium glycinate used is high.

[0142] Effect of reaction timeTo understand if the carbon mineralization reactions with Na-glycinate occur rapidly in the first hour of the reaction or gradually increases with time, carbon mineralization experiments were performed with Na-glycinate. The experiments were performed at 1, 3, and 5 hour time periods with 1 M Na-glycinate at 75 C. with a stirring rate of 300 rpm. The extents of carbon mineralization with CaO are 82.5, 94.2, and 95.9% at 1, 3, and 5 hours, respectively. The extents of carbon mineralization with CaSiO.sub.3 are 12.8, 31.0, and 34.6% at 1, 3, and 5 hours, respectively. Significant carbon mineralization occurs in the first hour of the reaction in the case of CaO. A small increase in the extent of carbon mineralization of CaO between 3 hours and 5 hours is noted. In contrast, the kinetics of carbon mineralization of CaSiO.sub.3 were considerably slower in the first hour of the reaction, with sufficiently high extents achieved at 31.0%. A small increase in the extent of carbon mineralization of CaSiO.sub.3 between 3 hours and 5 hours is noted (FIG. 16C). A progressive decrease in the intensity of the COO.sup. group in the aqueous phase is consistent with the higher extent of carbon mineralization (FIGS. 17C and 18C).

[0143] Structural and morphological characterization of recovered materialsDuring the carbon mineralization of CaO and CaSiO.sub.3, various forms of calcium carbonate such as calcite (rhombohedral), aragonite (spiky/orthorhombic), and vaterite (plate-like/hexagonal) can be formed. Prior studies showed that the process parameters such as the solvent for CO.sub.2 capture and the temperature influence the crystalline habit of calcium carbonate. Arti et al., Single Process for CO.sub.2 Capture and Mineralization in Various Alkanolamines Using Calcium Chloride, Energy & Fuels 31:763-769 (2017) and Murnandari et al., Effect of Process Parameters on the CaCO.sub.3 Production in the Single Process for Carbon Capture and Mineralization, Korean J. Chem. Eng. 34:935-941 (2017), both of which are hereby incorporated by reference in their entirety. To investigate the influence of temperature, amino acid salt concentration, and reaction time, the products were analyzed using Wide Angle X-Ray Scattering (WAXS) measurements. The carbonate-bearing products were identified and characterized in the presence of 1 M sodium glycinate at different temperatures of 25, 50, 75, and 90 C. for 3 h in FIG. 19A, with different concentration of 0, 0.5, 1, and 3 M sodium glycinate at 75 C. for 3 h in FIG. 19B, with 1 M sodium glycinate at 75 C. for different reaction time of 1, 3, and 5 hr in FIG. 19C. The changes in the functional groups in solid CaO and CaSiO.sub.3 when reacted to produce calcium carbonate are shown in FIGS. 22A-22C and 23A-23C, respectively.

[0144] CO.sub.2 absorption and mineralization at 25 C. in 1 M Na-glycinate results in the formation of Ca(OH).sub.2 and CaCO.sub.3. With increasing temperature, Ca(OH).sub.2 phase disappears and calcite remains as the dominant phase (FIG. 19A). Mller et al., Crystal Structure Refinement: A Crystallographer's Guide to SHELXL, Oxford Scholarship Online (2010); Chessin et al., Positions and Thermal Parameters of Oxygen Atoms in Calcite, Acta Cryst. 18:689-693 (1965); Wang et al., Structure and Carbonited Orientation of Vaterite (CaCO.sub.3), Am. Minerl. 94:380-386 (2009); Dal Negro et al., Refinement of the Crystal Structure of Aragonite, Am. Mineral. 56:768-772 (1971); Primak et al., X-Ray Diffraction Studies of Systems Involved in the Preparation of Alkaline Earth Sulfide and Selenide Phosphors, J. Am. Chem. Soc. 70:2043-2046 (1948); and Petch, The Hydrogen Positions in Portlandite, Ca(OH).sub.2, as Indicated by the Electron Distribution, Acta Cryst. 14:950-957 (1961), all of which are hereby incorporated by reference in their entirety. The presence of calcium hydroxide at 25 C. is consistent with the lower extent of carbon mineralization of 77.0% compared to 95.1%, 94.2% and 97.0% at 50, 75, and 90 C., respectively. Similarly, calcium hydroxide is present in the samples when reacted in water or 0.5 M Na-glycinate, which correspond to extents of carbon mineralization of 42.6% and 68.4% respectively (FIG. 19B). However, in the case of 3 M Na-glycinate, vaterite and calcite are co-present. These data suggest that higher concentrations of carbamate ions (FIG. 17B) in case of 3 M Na-glycinate influence the formation of calcium carbonate polymorphs. Further, increase in the reaction time enhances the formation of calcite (FIG. 19C). The morphological features are images using SEM. FIGS. 19A-19C represent unreacted CaO, CaO reacted in water and CaO reacted in 1 M Na-glycinate at 75 C. for 3 hours. The formation of rhombohedral calcite is noted when CaO is reacted in water and in 1 M Na-glycinate (FIGS. 19B and 19C).

[0145] Unlike CaO, lower extents of carbon mineralization are noted in CaSiO.sub.3. This is also evident from the presence of calcium silicate present in all the reacted samples. The co-presence of calcite, vaterite, and aragonite is noted in all the reacted samples (FIG. 20). Interestingly, the extent of carbon mineralization of CaSiO.sub.3 in water and 1.0 M Na-glycinate are 16.7% and 31.0%, respectively. For this reason, the presence of rhombohedral calcite, spiky aragonite and plate-like vaterite is more sparse in FIG. 19E representing the water case compared to FIG. 19F representing the 1.0 M Na-glycinate case.

Example 8Discussion of Examples 6-7

[0146] In the above examples, the single-step capture and mineralization of CaO and CaSiO.sub.3 to calcium carbonate using Na-glycinate, an amino acid salt is investigated. The influence of reaction temperature in the range of 25 C.-90 C., reaction time in the range of 1-3 hours, and Na-glycinate concentrations in the range of 0.5-3 M on the carbon mineralization behavior of CaO and CaSiO.sub.3 were probed. While lower temperatures aid the thermodynamics of CO.sub.2 capture, higher temperatures favor the kinetics of mineral dissolution and carbonate precipitation. In this single step CO.sub.2 capture and mineralization pathway, highest conversion of CaO and CaSiO.sub.3 were achieved at 1.0 M Na-glycinate at 75 C. and with a reaction time of 3 hours in a system comprising 15 wt % solid and at a stirring rate of 300 rpm. Extents of carbon mineralization with CaO and CaSiO.sub.3 are 94.2% and 31.0%, respectively. These data suggest that Na-glycinate undergoes multiple CO.sub.2 capture and regeneration cycles into the aqueous phase facilitating greater availability of aqueous carbon species for carbonate precipitation. The dominant crystalline phase in materials with CaO as the precursor is calcite. Aragonite, calcite and vaterite are present in the materials with CaSiO.sub.3 as the precursor. The results demonstrate that Na-glycinate is an environmentally benign alternative to aqueous amines for the single step CO.sub.2 capture and mineralization with inherent chemical regeneration of the solvent.

Example 9Novel Vortex-Flow Driven Process for Producing Calcium and Magnesium Carbonates Via Integrated CO.SUB.2 .Capture and Utilization (VORTEX-CO.SUB.2.)

[0147] The VORTEX-CO.sub.2 technology addresses the societal need of utilizing multiple waste streams such as alkaline industrial residues (e.g., steel slag and coal fly ash) and anthropogenic CO.sub.2 to produce value-added products. The customers for this technology are (i) industries that are experiencing challenges in disposing alkaline industrial residues rich in calcium and magnesium, and are interested in capturing and utilizing co-emitted CO.sub.2 (e.g., iron and steel industries, cement and construction industries) and (ii) industries that have a need for calcium and magnesium carbonates (e.g., paper and construction industries). The major pain points motivating this technology are the costs associated with the treatment and landfilling of alkaline industrial residues particularly steel slag (that has heavy metal constituents), opportunity cost of not using anthropogenic CO.sub.2 through the 45Q program which provides a tax credit of $35 per ton of CO.sub.2 captured and used, and the need for high purity calcium and magnesium carbonates with uniform size distributions to meet their growing demand for green building materials.

[0148] The value proposition lies in unlocking and realizing the economic value of using alkaline industrial residues or naturally occurring minerals and anthropogenic CO.sub.2 to produce value-added calcium and magnesium carbonates. Currently, there are no technologies on the market to simultaneously capture and convert CO.sub.2 using regenerable CO.sub.2 capture solvents to produce calcium or magnesium carbonates with uniform particle size distributions in less than three processing steps at temperatures in the range of 25-75 C. Thus, there is a need for novel, efficient, scalable, and commercially realizable processes for producing value-added inorganic carbonates from captured CO.sub.2.

[0149] To address this need, the innovation harnesses the use of localized vortex flows in a Taylor-Couette (T-C) reactor. This system accelerates the formation of calcium and magnesium carbonates with uniform particle size distributions while regenerating the aqueous CO.sub.2 capture solvent. Further, this innovation overcomes the challenge of non-uniform concentration gradients in conventional stirred systems that result in inconsistent particle size distributions of the crystallized materials.

[0150] A T-C reactor consists of two coaxial cylinders, with a rotating inner cylinder and fixed outer cylinder and inlets and outlets for continuous operation. Turbulent vortices are formed when the centrifugal force exceeds the stabilizing viscous force beyond a critical rotation speed. Vortex formation is simply controlled by the flow rate and the rotation speed of the cylinders. Localized mixing of the CO.sub.2-loaded solvent and the Ca- and Mg-species results in uniform particle size distributions of Ca- and Mg-carbonates and the regeneration of the solvent in customized T-C reactors. By tuning the flow rate and the rotation rate, particles can be synthesized with sizes ranging from a few tens of nanometers to several micrometers. This technology will disrupt conventional approaches of synthesizing calcium and magnesium carbonates and will allow customers to harness the existing 45Q tax reforms for capturing and utilizing anthropogenic CO.sub.2.

[0151] Studies demonstrated that T-C reactors overcome the challenges of non-uniform flow and concentration fields in conventional stirred reactors that result in inconsistent particle size distributions. Thus, T-C reactors provide the unique opportunity to accelerate CO.sub.2 capture and carbonate crystallization processes while producing carbonate particles with uniform and consistent particle size distributions.

[0152] Over the past century, scientists have developed technical expertise in harnessing abundant fossil carbon resources to meet energy needs. There is now a growing societal realization that these activities are contributing to rising CO.sub.2 concentrations in the atmosphere and have detrimental environmental impacts, despite the economic and social benefits that these technologies have brought to humanity. To advance market-driven solutions, emerging technologies that provide economic incentives to curb current CO.sub.2 emissions into the atmosphere, and utilize these emissions are needed. These societal and economic needs motivated the development of integrated CO.sub.2 capture and utilization technologies to produce value-added products such as calcium and magnesium carbonates.

[0153] Calcium carbonates (CaCO.sub.3) are widely used as aggregates for building roads, additives in drilling fluids, and filler materials in the paper industry. Magnesium carbonates (MgCO.sub.3) are used as filler materials in cosmetics, toothpaste, and in flooring materials. These needs are typically met by mining naturally occurring carbonates, as opposed to utilizing anthropogenic CO.sub.2. For certain construction-related applications, these naturally occurring carbonates are calcined i.e., CaCO.sub.3 and MgCO.sub.3 are heated to temperatures as high as 750-850 C. and 350-400 C., respectively to produce oxides and emit CO.sub.2. Calcination of naturally occurring CaCO.sub.3 is one of the largest contributors to CO.sub.2 emissions from cement industries. Naturally occurring MgCO.sub.3 is also calcined to produce MgO which is used in bricks. Cost-effective processes that can reuse anthropogenic CO.sub.2 to produce synthetic carbonates can meet these needs. Certain applications of these carbonates as filler materials can store CO.sub.2 for long periods of time. These environmental factors motivate the development of new technologies for carbon capture and utilization, with implications for storage for specific applications.

[0154] Another societal challenge is the large quantities of Ca- and Mg-rich industrial residues that cost industries time, effort, and money to process and dispose in landfills. Examples of these wastes include iron and steel slag generated during the iron and steel making processes, cement kiln dust produced during the production of construction materials, fly ash generated in coal-producing facilities, and red mud generated in aluminum industries. FIG. 24 represents the production rates of these materials and the associated content of Ca and Mg. Novel processes that can utilize these residues to produce value-added products such as carbonates can reduce the associated wastes. It is estimated that 200-300 million tons of CO.sub.2 can be captured and stored as carbonates in these alkaline industrial residues globally every year. To date, there is no technology to (i) synthesize anthropogenic carbon-bearing materials with specific particle sizes without the need for additional post-processing steps such as grinding, (ii) accrue carbon credits by offsetting CO.sub.2 emissions, and (iii) eliminate tipping fees for disposing alkaline residues.

[0155] Several pain points were identified in the current market that the VORTEX-DAC technology can address. These pain points include the costs associated with the treatment and landfilling of alkaline industrial residues particularly steel slag, opportunity cost of not capturing and utilizing CO.sub.2 through the 45Q program which provides a tax credit of $35 per tonne of CO.sub.2 captured and used, and the need for CaCO.sub.3 and MgCO.sub.3 to meet their growing demand in various industrial sectors.

[0156] Inorganic carbonates such as Ca- and Mg-carbonates have several applications depending on the purity and the morphological specificity of these materials. High purity Ca- and Mg-carbonates can be used in filler materials. This technology has the potential to produce high purity silica that has several industrial applications. Low purity carbonates co-present with silica can be used in construction and building materials. This technology leverages the growing market for global green building materials which is currently estimated at USD 192.3 billion with an approximate growth rate (CAGR) of 11.2% in 2016. Table 4 summarizes the current global market for carbonates, applications, and the selling price.

TABLE-US-00004 TABLE 4 Current global market for carbonates, summary of applications, and estimated selling price Fraction of Estimated Current global global Selling market Application market Price High purity USD 3.3 billion in Plastic, Rubber, 1% --> $85/kg nano- 2018 and is Building and USD (98%, calcium expected to witness Construction 33.19 50 nm) carbonate a CAGR of 8.9% million from 2019 to 2025 Calcium USD 22.95 billion Paper, Paints and 1% --> $18/kg carbonate in 2018 and is Coatings, Plastics, USD estimated to witness Adhesives and 230 a CAGR of 7.4% Sealants Million from 2019 to 2025 Magnesium USD 67 million in Pharmaceuticals, 1% --> $294/kg carbonate 2020 currently and Plastic & Rubber USD is expected to reach Industry, Personal 670,000 USD 80 million by Care & Cosmetics, the end of 2026, Paints & Inks, growing at a Pulp & Paper CAGR of 2.5% Industry, Food & during 2021-2026 Beverage Precipitated USD 1.96 billion in Rubber, 1% --> $2030/kg silica 2018 and is expected Agrochemicals, USD (nano to expand at a Oral care, Food 1.96 powder) CAGR of 7.9% million

[0157] These analyses are important when considering customizing the technology to meet customer needs. Two principal categories of end customers were identified: 1) those who need high purity carbonates for use as specialty minerals or chemicals. Examples of these customers include whole-sale distributors or sellers of chemicals, pharmaceutical companies that use high quality filler materials, and paper industries; 2) those with a strong need to convert alkaline industrial residues using CO.sub.2 as opposed to disposing them.

[0158] This technology can be scaled-up to produce customized particle sizes of CaCO.sub.3 or MgCO.sub.3 or implement it at industries that are looking to offset the cost of treating alkaline industrial residues and utilize the 45Q tax credits for capturing and utilizing CO.sub.2. Examples of these customers include iron and steel manufacturers, cement manufacturers, aluminum producers, and fly ash generators such as coal-fired power plants. Even with partial market penetration, this volume would be sufficient for the manufacturer of the reactor systems to benefit from the strong price scaling and provide cash-flow to support continued research and development and identify diverse customers and markets.

[0159] The innovation is in the synthesis of carbonates with uniform particle morphologies using CO.sub.2 captured by aqueous solvents that are regenerated as the carbonates are formed. Well-defined particle sizes are achieved in a specialized Taylor-Couette Carbonate Conversion (also referred to herein as TC.sup.3) reactor. This specialized reactor system is integrated with an absorption column for CO.sub.2 capture. The two scientific principles underlying this innovation are: (i) CO.sub.2 capture solvents are chemically regenerated in alkaline environments in which dissolved calcium and magnesium react to produce calcium and magnesium carbonates, and (ii) turbulent vortex flows enhance localized mixing which accelerates solvent regeneration and carbonate formation.

[0160] Significant energy savings are realized in this innovation compared to conventional CO.sub.2 capture and thermal regeneration of solvents. Solvent regeneration and carbonate formation occurs simultaneously at 50-75 C. as opposed to the thermal regeneration of the solvent which occurs at 120-140 C. In particular, the use of alkaline industrial residues or alkaline-bearing fluids allows for the simultaneous treatment of alkaline residues (e.g., steel slag, fly ash) and CO.sub.2 emissions. FIG. 25 is a schematic representation of the CO.sub.2 absorption and the solvent regeneration process to produce carbonates in the TC.sup.3 reactor. During the installation of the reactor, the process engineers are provided with unprecedented capabilities to customize the setup to treat the specific alkaline industrial residue of interest. Post-installation, the performance of the reactor and the carbonate conversions achieved will continue to be monitored.

[0161] A key component of this invention is the demonstration of the solid Ca- and Mg-carbonate formation with inherent solvent regeneration. The effectiveness of amine-based solvents such as monoethanolamine (MEA) and amino acid salt solvents such as sodium glycinate have been demonstrated in producing Ca- and Mg-bearing solids with solvent regeneration. Compared to MEA, sodium glycinate is less corrosive and more environmentally benign with similar performance for CO.sub.2 capture and regeneration. One molecule of sodium glycinate captures one molecule of CO.sub.2, while two MEA molecules are needed to capture one molecule of CO.sub.2. Near complete conversion of CaO to CaCO.sub.3 is achieved using MEA (FIG. 26) and sodium glycinate (FIG. 27) at 50 C. after reacting for 3 hours in a stirred tank reactor. In comparison, about 35% conversion of CaSiO.sub.3 is achieved at 50 C. with MEA and at 75 C. with Na-glycinate. The particle sizes of CaO and CaSiO.sub.3 are in the range of 10-30 m. However, one of the key challenges with stirred reactor systems is the development of concentration gradients and flow fields with distance from the impeller resulting in non-uniform particle size distributions.

[0162] The T-C reactor provides vortex flows that accelerate the kinetics of solvent regeneration and carbonate formation. Prior research efforts demonstrate that vortex flows in T-C reactors result in narrower and well-defined particle size distributions of crystalline materials. This approach is an alternative to the conventional approaches of grinding carbonates post-synthesis to produce materials with specific particle sizes.

[0163] Another less explored technical challenge is the synthesis of carbonate-bearing materials with morphological specificity, starting from alkaline industrial precursors. Prior studies focused on the synthesis of carbonates from alkaline industrial residues were performed in stirred tank reactors using non-regenerable chemicals such as acids and bases. In contrast, this VORTEX-CO.sub.2 technology represents a step-change advancement over the existing approaches given the use of regenerable solvents.

[0164] In June 2020, DOE targets called for reducing the cost of CO.sub.2 capture to about $30/ton of CO.sub.2. This technology is estimated to cost $20-$30/ton of CO.sub.2 since the chemical regeneration of the solvent occurs at substantially lower temperatures compared to thermal generation. Further, this cost does not include the avoided cost of disposing alkaline industrial residues in landfills which is estimated to cost $55/ton in the United States and the potential revenue from selling the produced carbonates. Studies have shown that replacing Ordinary Portland Cement (OPC) with 10% carbonated stainless steel slag (cSSS) results in a significant increase in the compressive strength of construction materials (FIG. 28). These data illustrate the effectiveness of these carbonate-bearing materials in enhancing the compressive strength of cementitious materials.

[0165] One of the unique features of the VORTEX-CO.sub.2 technology is that it can be integrated with absorption technologies (e.g., amino acid salts or amines) for CO.sub.2 capture. The chemical regeneration of the solvent with inherent formation of Ca- or Mg-carbonates occurs at 50-75 C., which is substantially lower compared to the thermal regeneration of the solvent which occurs at 100-140 C. depending on the solvent type. Thus, the VORTEX-CO.sub.2 technology can harness waste heat in an industrial or power plant facility.

[0166] Prior approaches for producing carbonates utilized chemically consumptive pH swing approaches that utilize strong acids (e.g., hydrochloric acid or nitric acid) to dissolve the Ca and Mg constituents and precipitate carbonates at high pH conditions for which strong bases such as sodium hydroxide are used. In contrast, the inherent regeneration and reuse of the sodium glycinate solvent is chemically and energetically efficient.

[0167] Alkaline industrial residues such as steel slag and coal fly ash are produced to the order of several million tons every year. Landfilling these materials is often complicated by the presence of corrosive constituents such as nickel and chromium. Therefore, the conversion of these materials to carbonates is suggested to reduce their alkalinity, and lock in the heavy metals in a solid matrix. These alkaline industrial residues are often co-generated with CO.sub.2 on-site. The availability and compositions of fly ash produced from coal-fired power plants, steel slag generated during steel manufacturing, cement kiln dust produced during cement manufacturing, and red mud generated during aluminum production are shown in FIG. 24. The heterogeneity in the compositions of these materials is represented by the large error bars in this figure.

[0168] FIG. 29 represents the availability of alkaline industrial residues and the corresponding CO.sub.2 emissions. From this figure, it can be inferred that the mining industry has sufficient residues to offset its CO.sub.2 emissions. However, the CO.sub.2 emissions in power generation, iron and steel production, cement and aluminum production exceed the availability of these residues. About 200-300 million tons of CO.sub.2 can be stored in these residues and 10.sup.4-10.sup.6 gigatons of carbon can be stored in naturally occurring minerals. Thus, novel, cost-effective, and environmentally beneficial technologies that can harness these resources and deliver value to customers are needed.

[0169] Construction and carbonate materials from anthropogenic CO.sub.2The concept of curing synthetic Ca-silicate materials to produce construction materials using CO.sub.2 has been well developed and deployed. This unique technology harnesses the carbon mineralization behavior of synthetic Ca-silicate to produce high strength constructions materials. Alternatively, CO.sub.2 is injected into wet concrete to react with Ca in cement to produce nano-sized CaCO.sub.3 which strengthens concrete. However, these technologies need a separate CO.sub.2 capture and compression step to produce high purity and pressurized CO.sub.2 and do not utilize CO.sub.2 in flue gas streams directly.

[0170] Treatment of alkaline industrial residues with CO.sub.2There is technology to convert steel slag into carbonates in their facility in Inner Mongolia. This technology was implemented based on the concept of pH swing where acidic solutions are used to enhance the dissolution of Ca and Mg constituents and aid silica precipitation. Basic solutions aid the formation of solid Ca- and Mg-bearing carbonates. The challenge with this technology is the significant consumption of acids and bases. This technology involves multiple unit operations and the recovery of the reagents is challenging. Thus, there is a market need for technologies that directly utilize regenerable solvents and flue gas streams in fewer unit operations to produce value-added products with specific morphologies.

[0171] CO.sub.2 capture from flue gasSolvents, sorbents, or membranes are conventionally used to capture CO.sub.2 from flue gas streams. In the case of solvents, changes in temperature (or temperature-swing) are used to recover high purity CO.sub.2. In the case of solvents, temperatures in the range of 120-140 C. are typically needed to regenerate CO.sub.2-loaded solvents. These solvent-based processes via thermal regeneration have been commercialized. Alternatively, the solvents can be regenerated chemically using salt solutions such as CaCl.sub.2 and the resulting product is CaCO.sub.3. Chemical regeneration of the solvent occurs at temperatures lower than 90 C., which is significantly lower than the temperatures needed for thermal regeneration. Given the high content of Ca or Mg in alkaline residues, these materials are well-suited for carbonate formation and solvent regeneration. However, the use of novel reactor systems that harness vortex flows to accelerate the regeneration of solvents and produce particles with morphological specificity has not been reported.

[0172] The hardware components and products and services that distinguish this technology are discussed below.

[0173] HardwareThe TC.sup.3 reactor is designed to produce carbonate-bearing materials via the regeneration of amine or amino acid solvents (e.g., sodium glycinate). This system comprises a rotating inner cylinder and a fixed outer cylinder with two inletsone for the CO.sub.2-loaded solvent and another for the alkaline residues, and an outlet for the product stream. The chemical interactions between the CO.sub.2-loaded solvent and the alkaline residues and the kinetics of carbonate formation are tuned by changing the rotation speed of the inner cylinder and the flow rates which influence the axial flow and mixing behavior. This reactor is customized to include pH probes and sample withdrawal ports to track the reaction progress. Temperature probes and sensors are incorporated. The pH and temperature sensing elements operate with simple, common electrical interfaces that are compatible with existing wired and wireless logging equipment and with integrated wireless solutions. The reactor configuration will be adapted based on the type of alkaline industrial residue being treated and the carbonates of interest. The service of determining the conversions and kinetics is also provided for customizing the reactor configuration.

[0174] Products and Services. As an integral part of the proposal, the TC.sup.3 reactor prototypes will be used to begin the development of standard methods for producing a range of carbonate-bearing materials with specific particle sizes, along with the kinetics of regeneration of the CO.sub.2-capture solvent. To produce high purity Ca- or Mg-carbonates, Ca and Mg can be extracted from the alkaline industrial residues using low pH solutions and supply these solutions to the TC.sup.3 reactor. The particle size distributions of these materials will be determined and supplied to potential customers.

[0175] For companies that are interested in treating their waste on-site to produce value-added products, a scale-up analyses of the integrated CO.sub.2 capture and TC.sup.3 reactor configuration will be supplied. This reactor scheme can also be deployed for on-site processing of alkaline industrial residues. The chemical compositions of these residues can be characterized and the carbonate conversions and kinetics of solvent regeneration can be tested in the reactor. The long-term objective is to supply a range of carbonate-bearing products based on varying particle sizes and purity to meet specific market needs using the TC.sup.3 reactor. This process is an alternative to energy intensive grinding or comminution processes for producing carbonates needed post-processing to obtain specific particle sizes. Thus, the energy demand and cost of synthesizing these carbonates is expected to be substantially lower compared to conventional grinding approaches. The knowledge gained during these laboratory experiments lays the foundation for a new class of processing routes for producing Ca- and Mg-carbonates and remediation services of alkaline industrial residues.

[0176] The hypothesis is that the VORTEX-CO.sub.2 technology will need to be adapted for producing two types of materials: high purity Ca- and Mg-carbonates and particles with mixtures of carbonates and silica. To produce high purity Ca- or Mg-carbonates, Ca- or Mg-rich solutions obtained post-extraction from alkaline industrial residues, and the CO.sub.2-loaded aqueous solvent such as sodium glycinate will be used. This setup involves liquid-liquid contacting resulting in the precipitation of high purity Ca- and Mg-carbonates. To directly convert alkaline industrial residues to Ca- and Mg-carbonates, uniformly ground alkaline residues will be contacted with the CO.sub.2-loaded solvent, thus involving solid-liquid contacting and simultaneous dissolution of the residues and solid carbonate formation. Thus, there is a need to develop a calibrated understanding of the reactivities of the alkaline industrial residues as a function of the composition and morphology of these materials. This information is needed to inform the scale-up of the customized TC.sup.3 reactor.

[0177] Design the TC.sup.3 reactorThe goal is to develop a customized Taylor-Couette Carbonate Conversion (TC.sup.3) reactor for producing Ca- or Mg-carbonates with uniform particle size distributions and regenerating the solvent. This T-C reactor system consists of two coaxial cylinders, with a rotating inner cylinder and fixed outer cylinder and inlets and outlets for continuous operation. FIG. 29 is a schematic representation of the T-C reactor. Flow driven by cylinder rotation results in azimuthal laminar flow and an axisymmetric cellular fluid motion. The destabilizing centrifugal force exceeds the stabilizing viscous force when the transition from purely azimuthal laminar flow to an axisymmetric cellular fluid motion occurs beyond a critical rotation speed. The critical Taylor number (T.sub.ac) will be determined for the system comprising the CO.sub.2-loaded solvent and Ca- or Mg-bearing species that determines the hydrodynamic instability and marks the Taylor-Couette flow (TCF) regime.

[0178] Uniformly spaced counter-rotating cellular vortices, with each pair forming an axial wave, is characterized by critical wavenumber (a.sub.c) and wavelength (.sub.c). The flow between the concentric cylinders is divided into cellular elements, each of which consists of counter-rotating vortices. Because these vortex pairs are usually equal in size, it is assumed that mixed fluid is uniformly distributed along the vortices, so that it spends identical residence time in each cellular element. Mathematical expressions representing the Taylor number and Axial Reynolds number are represented below.

[00004]$\begin{array}{cc}\mathrm{Taylor}\mathrm{number}:T_a=\frac{2r_i^2{d}^4}{r_o^2-r_i^2}{\left(\frac{{}_i}{v}\right)}^2& \left(1\right)\end{array}$$\begin{array}{cc}\mathrm{Axial}\mathrm{Reynolds}\mathrm{number}:R_{e_z}=\frac{Q}{\left(r_i+r_o\right)v}& \left(2\right)\end{array}$

[0179] In these expressions, r.sub.i, r.sub.o, and d represent the inner radius, outer radius, and the differences in these radii. The angular velocity of the inner cylinder and the kinematic viscosity are represented by .sub.i and , respectively. Q represents the axial flow rate of the inlet solution and is calculated as:

[00005]$Q=\frac{\mathrm{Volume}\mathrm{flow}\mathrm{rate}}{\mathrm{Cross}\mathrm{sectional}\mathrm{area}\mathrm{of}\mathrm{the}\mathrm{tube}}$

[0180] The morphology of the particles is tuned based on the residence time in the reactor, which is controlled by the Axial Reynolds number R.sub.e.sub.z. To produce larger particles, more collisions are indeed which is achieved through a smaller R.sub.e.sub.z by tuning the flow rate of the inlet solution, Q. Therefore, the T-C reactor provides direct access to the axial flow rate and angular velocity to tune the chemical interactions. These flow rates will be tuned to achieve fast kinetics and high conversions.

[0181] Important features of the TC.sup.3 reactorThe laboratory-scale TC.sup.3 reactor is designed specifically to have a pH probe, temperature controls, and sampling ports to evaluate changes in the composition. The ratio of the inner and outer radii and the gap between the inner and outer cylinders is tuned to achieve vortex flows. The inner cylinder rotation rate is controlled by a phase inverter, connected to a motor drive that provides rotation rates in the range of 30-1800 rpm. The reactor is operated in a horizontal configuration since significant changes in the interfacial area with increasing rotational speed are achieved in this configuration as opposed to a vertical configuration (FIG. 30A). The transition from laminar Taylor Couette flow to turbulent Taylor vortex flow are estimated from flow visualization experiments. The lab-scale prototype has inner and outer cylinder dimensions of 0.0227 m and 0.0253 m with the ratio of inner and outer radii of 0.9. The reactor length and volume are 0.3 m and 117 ml, respectively. This prototype reactor will be scaled up to meet the specific requirements of the customers.

[0182] The onset of Taylor-Couette vortex flows is determined from flow visualization (FIG. 30B). Light reflectance off specific particles is used to make the flow field visible. Pigmented titanium dioxide coated mica flakes (432 microns, 3.1 g/ml, from Kalliroscope Corporation) will be used. These particles align themselves with the local shear stress direction, and light reflectance off these particles will enhance the visibility of the flow field. The onset of instability is marked by alternating light and dark bands indicating the presence of counter-rotating Taylor vortices. To create an opaque and highly light scattering solution, the flakes were added to the fluids at a volume fraction of 210.sup.5. The observer incident light will be reflected back resulting in the white coloring of the local fluid, when the face of the mica flakes is oriented towards the observer. The spacing of each white fluid region corresponds to differences in the orientation of the flow-aligned mica particles, which characterize the shape and length of the formed vortices. Different flow regimes were identified via flow visualization using a high speed CCD video camera, which acquired and stored the images directly in 256 shades of gray. The on-board memory is sufficient for 3300 images, which can be captured at any rate up to 1000 Hz. To adjust image quality for different operating conditions, parameters, such as, exposure, image capturing rate (Hz), and movie playing speed (frames per second) were modified accordingly. Spectral image analysis is done through a procedure that is applied using a software written on the basis of Matlab. By applying a fast Fourier transform (FFT) algorithm to the intensity profile, a discrete Fourier transform is then adjusted to obtain a.sub.c.

[0183] A plexi-glass outer cylinder of the TC.sup.3 reactor will be used for visualization to determine the critical Taylor number, and machine ports for pH probes, temperature sensors, and periodic fluid sampling in the TC.sup.3 reactor. Instead, the gap between the inner and outer cylinders is kept relatively small (i.e., ratio of inner cylinder radius to outer cylinder radius is 0.9) to increase the number of vortices and the axial flow. An absorber for CO.sub.2 capture is used that will be connected to the TC.sup.3 reactor.

[0184] Develop calibration methods for the TC.sup.3 reactorThe aim is to develop calibration methods to ensure that the TC.sup.3 reactor is functioning effectively. one calibration approach that involves the use of Ca(OH).sub.2 and CO.sub.2 gas to produce nano-scale CaCO.sub.3. This approach is described below.

[0185] Calcium hydroxide (Ca(OH).sub.2) at a concentration of 2.5 wt % is reacted with CO.sub.2 gas in a T-C reactor to produce CaCO.sub.3 as represented by this reaction: Ca(OH).sub.2+CO.sub.2.fwdarw.CaCO.sub.3+H.sub.2O. The loading of 2.5 wt % is about 16 times its saturation solubility of CaCO.sub.3. The resulting pH of the solution is 12 at the beginning of the experiment. The remaining Ca(OH).sub.2 remains suspended in this slurry. The initial temperature is maintained at 20 C. The inner walls of the reactor were carefully rinsed with dilute acetyl acid solutions and distilled water to minimize precipitation on the surfaces. A peristaltic pump is used to fill the reactor and pump fluid. The experiments are performed at gas flow rates of 0.5 L/min. A change in the pH from 12 to 7 is indicative of the completion of the reaction. When the Ca(OH).sub.2 phase is completely consumed, after which the pH reaches a steady-state of 6. pH is measured every 30 seconds. 60 ml of the final suspension is collected and centrifuged at 6500 rpm for 15 minutes to collect the nanoparticles.

[0186] The samples are washed once with deionized water, centrifuged once again at the same conditions and then dried at 110 C. for 1 hour to remove all remaining moisture, before characterizing the PCC product properties. The particle size distributions of the obtained PCC were determined using dynamic light scattering (DLS) measurements at CO.sub.2 flowrates of 0.02 and 0.1 L/min.

[0187] Preliminary data was collected to demonstrate the effectiveness of this approach in producing nano-scale CaCO.sub.3 as shown in FIGS. 31A and 31B. The reduced Taylor number, Tar is the ratio of the actual Taylor number and the critical Taylor number. As shown in FIGS. 31A and 31B higher reduced Taylor numbers and CO.sub.2 concentrations result in smaller particle sizes with narrower distributions. The fraction of monodispersed particles was observed to increase with higher rotation rates, especially when reaching fully developed turbulent Taylor vortex flow (TTVF). The ultrasonic treatment of the crystals minimized the potential for bimodality associated with tertiary agglomeration. This calibration approach will be expanded include a wider range of temperatures (25-90 C.), wider range of Ca(OH).sub.2 concentrations (2.5-15 wt %) and wider ranges of flow rates (0.02-5 L/min). In addition to CO.sub.2 gas, a calibration approach will be developed using CO.sub.2-loaded sodium glycinate and Ca(OH).sub.2 as a representative calibration base case.

[0188] Potential risks and mitigation strategy. Unanticipated effects of flow rates and rotation speeds resulting in non-uniform particle size distributions from one batch to another is a risk. During the calibration stage, the experimental bounds of flow rates, rotation speeds, and chemical compositions for producing uniform particle size distributions of carbonates will be determined.

[0189] Accelerate the kinetics of CO.sub.2 capture and carbonate conversion using TC.sup.3 reactorThe aim is to demonstrate the kinetic enhancement in carbonate conversions and solvent regeneration using the TC.sup.3 reactor compared to conventional reactor systems. To realize this aim, the chemical compositions and morphologies of industrial and mining residues will be characterized protocols will be developed for preparing input feedstreams to either produce high purity Ca- or Mg-carbonates or particles with carbonates and silica, the kinetics of carbonate conversion will be determined, and process-scale, techno-economic, and life cycle assessments will be developed as discussed below.

[0190] Characterize the chemical compositions and morphologies of industrial and mining residuesVarious alkaline industrial residues will be procured such as steel slag, coal fly ash, cement and lime kiln dust, and Mg-rich mining residues from the United States Geological Survey (see letter of support). Some naturally occurring Ca- and Mg-silicate minerals (e.g., Mg.sub.2SiO.sub.4, CaSiO.sub.3, MgSiO.sub.3) will be obtained that are abundant in these alkaline industrial residues for testing. The elemental composition of these materials will be determined using X-Ray Fluorescence (XRF). X-ray diffraction (XRD) measurements will be performed to determine the compositions of various crystalline phases such as oxides, hydroxides, or silicates of Ca, Mg, Na, or K present in these materials. The particle sizes will be determined using light scattering measurements. BET analyses will be performed to determine the pore size distributions and the surface areas of these materials. Commercially available pure precursors will be procured such as Ca- and Mg-oxides, hydroxides, and silicates for a systematic comparison.

[0191] Develop a strategy for producing pure carbonates and particles bearing carbonates and silicaTo produce high purity carbonates (>95% CaCO.sub.3 or MgCO.sub.3 by molar mass), solutions rich in Ca- or Mg obtained from alkaline industrial residues will need to be used. To obtain Ca-rich solution, Ca-rich industrial residues such as coal fly ash or steel slag are dissolved in nitric acid. Mg-rich solutions are obtained by dissolving mining residues such as Mg-silicate bearing materials remaining after the extraction of Ni or Fe in nitric acid. These concentrations will be analyzed using ICP-AES. One important consideration is the abundance of iron co-present. Iron constituents will be separated by increasing the pH to 5-6 which causes the precipitation of iron oxide. The resulting Ca- or Mg-rich solution is used in the studies. To directly convert industrial residues such as coal fly ash and steel slag, these materials are ground to consistent particle sizes of 10-20 m, which is known to result in high conversions. The goal is to develop alkaline input feed streams to produce high purity carbonates and particles with carbonate and silica constituents.

[0192] Determine the influence of solvent and alkaline industrial residues on CO.sub.2 capture and carbonate conversionThe aim is to determine the kinetic enhancement in carbonate conversion and solvent regeneration using the TC.sup.3 reactor. The hypothesis that higher carbonate yields and faster residence times are achieved using the TC.sup.3 reactor compared to stirred reactors will be tested. The influence of various CO.sub.2-loaded aqueous solvents such as sodium glycinate, monoethanoamine (MEA), diethanolamine (DEA), piperazine (PZ), 2-amino-2-methyl-1-propanol (AMP) and methyl diethanolamine (MDEA) on producing high carbonate yields in the TC.sup.3 reactor (see FIG. 32 for the chemical structures) will be evaluated. These are some of the commonly studied solvents, and various blends incorporating this family of solvents has been recommended for CO.sub.2 capture. The compositions of these amines in the range of 10-50 wt %, dissolved Ca- or Mg-rich solutions with concentrations ranging from 0.1-1M, and the ground alkaline industrial residues with slurry compositions of 5-50 wt % will be studied. The input streams that are prepared will be used in these studies. Select experiments will be performed using pure precursors such as the oxides, hydroxides and silicates of Ca and Mg for a consistent comparison. Alkaline industrial residues are often rich in silica which can limit reactivity. The hypothesis that turbulent vortex flows enhance fluid-solid contacting, thus resulting in more uniform particle size distributions will be tested.

[0193] The flow rates and rotation speeds that result in carbonate conversions >80% and faster residence times compared to conventional stirred systems will be determined. The hypothesis that these conversions will be achieved much faster in a TC.sup.3 reactor and that the particle size distributions are more reproducible and uniform will be investigated. Concurrent experiments will be performed in a semi-batch stirred reactor to compare the kinetics and size distributions of these materials. The carbonate content will be determined using thermogravimetric analyses, and the solvent composition will be determined using quantitative ATR-FTIR and NMR measurements. The particle size distributions will be determined using laser diffraction and zeta sizer analyses. The goals is to quantify enhancement in kinetics of carbonate formation and solvent regeneration in the TC.sup.3 reactor compared to stirred systems. The success metric is two-fold enhancement in the kinetics of carbonate formation and solvent regeneration in TC.sup.3 reactor compared to conventional stirred reactor systems.

[0194] Slower kinetics and longer residence times compared to continuously stirred reactor systems are major risks. Entrainment and deposition of particles at the inlets or outlets and unanticipated chemical changes in these materials could be some of the causes. To delineate entrainment or deposition effects, flow visualization will be used. To probe the effects of unanticipated chemical changes, experiments will be performed with pure material precursors such as commercial oxides, hydroxides and silicates of Ca and Mg. If direct use of alkaline industrial residues is a challenge, Ca- and Mg-hydroxides will be produced and used.

[0195] Process-scale and techno-economic assessments, life cycle analyses, and scale-up strategies for commercializing the VORTEX-CO.sub.2 technologyThe aim is to develop process scale assessments for the VORTEX-CO.sub.2 technology to capture and convert 1 ton of CO.sub.2/day. The influence of CO.sub.2-bearing flue gas streams with compositions ranging from 1-100 vol % will be evaluated. ASPEN Plus simulation software will be used to size the equipment based on the kinetic parameters determined from the disclosure. Appropriate models such as the electrolyte-NRTL property method will be utilized to account for thermodynamic behaviors in multiphase reaction environments. The sensitivity to process variables such as temperature, aqueous solvent chemistry, and slurry compositions on the sizes of the process units will be evaluated. The energy needs associated with operating the TC.sup.3 reactor will be analyzed. These assessments will be connected to the cost of mineral processing and process scale evaluations. The overall net carbon that is captured and stored will be assessed using hybrid Economic Input-Output Life Cycle assessments. These insights will be used to determine if this technology can be commercialized through licensing, or if a plant will be built to convert alkaline industrial residues and CO.sub.2 into value-added products. The commercial value of the end-products as shown in Table 4 will be evaluated. The tax incentives provided by the 45Q program will be considered when developing the commercial strategy in North America. The goal is determination of mass, energy flows and associated costs normalized to one ton of CO.sub.2 captured. The success metric is identification of reaction parameters that result in cash positive (net estimated profits >$10/ton of CO.sub.2 captured) and net carbon storage potential. Customers who will use the materials in the carbonate form, as opposed to regenerating CO.sub.2 will be identified.

Example 10Integrated Direct Air Capture and Removal Via Accelerated Carbon Mineralization Synergistically Using Alkaline Industrial Residues, Minerals or Mine Tailings and Chloride-Rich Brines

[0196] The aim of this project is to accelerate carbon mineralization in remote locations with silicate minerals, industrial residues and mine-tailings (e.g., kimberlite tailings generated during diamond mining), where the lack of access to point-source emissions of CO.sub.2 and processing water with low salt concentrations are current barriers to deployment. One of the less explored, but highly transformative routes to accelerate carbon mineralization is through hybrid absorption-crystallization pathways, in which CO.sub.2 from air is captured by using regenerable, environmentally benign solvents, such as sodium glycinate. CO.sub.2-loaded solvents react to produce magnesium carbonate, while regenerating the solvent. Simultaneously, acid (HCl) and bases (NaOH, Ca(OH)2, and Mg(OH)2) can be electrochemically produced from brines recovered from geological carbon storage in remote locations. The acids can then be used to accelerate the dissolution of the magnesium silicate minerals abundant in mine tailings, and the alkaline earth bases can be mineralized into Ca- and Mg-carbonates. In turn, the NaOH can be used to regenerate the sodium glycinate solvents. A schematic of the proposed concept is shown in FIG. 33.

[0197] This integrated process overcomes challenges associated with inadequate availability of concentrated point source emissions of CO.sub.2 and processing water at mine tailings disposal sites. Modular and coupled technologies are needed to address these challenges, along with beneficiation of multiple waste streams such as industrial residues, brines and CO.sub.2, producing value products to off-set processing costs (silica and precipitated carbonates), and potentially generating carbon credits or carbon off-sets for trading. With rising penetration of low-cost renewable electricity expected over the course of the next 5-10 years, economical scale-up of the electrochemical decomposition of brines will be increasingly favorable. The project is timely given recent evidence of the effectiveness of hybrid absorption-carbonate crystallization with inherent solvent (e.g., Na-glycinate) regeneration. Na-glycinate solvents have been proposed as an environmentally benign alternative, with comparable CO2 capture rates, to corrosive and thermally- or oxidatively-degrading amines, such as monoethanolamine. Another timely and less explored topic is the utilization of brines to produce acids and bases through modular electrochemical processes. Management of chloride-rich brines generated from industrial and mining processes and due to their displacement from deep saline aquifers for CO.sub.2 injection and storage is another emerging societal challenge. Electrochemical strategies to utilize these brines are proposed which can be synergistically applied in other applications requiring brine treatment. Synergies in direct air capture of CO.sub.2, recovery of value-added acids and bases from corrosive and low-value brines, and thermodynamically downhill carbon mineralization pathways are harnessed to create disruptive integrated technologies for accelerated CO.sub.2 removal.

Example 11Designing A Prototype Taylor-Couette Crystallizer for the Integrated and Low Temperature CO.SUB.2 .Capture, Conversion and Storage to Produce Calcium Carbonate with Morphological and Structural Specificity

[0198] Designing and translating energetically and atomistically efficient engineering solutions into practice is critical to address the grand societal challenge of producing energy and resources while reducing detrimental environmental impacts. Specifically, adaptive and modular systems are needed to curb the unabated emissions of greenhouse gases (e.g., CO.sub.2) from wide ranging sources including CO.sub.2 produced from anaerobic digestors, facilities producing cement, iron and steel, and coal- or natural gas-fired power plants. This perspective has led to address the question: How to design an adaptive device to accelerate the capture, conversion and storage of CO.sub.2 from point source emissions via thermodynamically downhill pathways? Addressing this challenge requires demonstration of the scientific viability of the chemical pathways and the process for implementing these pathways. Towards this end, an Aqueous Alkaline Amine Looping (A3L) pathway was developed to simultaneously convert and store CO.sub.2 as calcium carbonate (CaCO.sub.3) at temperatures below 90 C. Liu & Gadikota, Integrated CO.sub.2 Capture, Conversion, and Storage To Produce Calcium Carbonate Using an Amine Looping Strategy, Energy & Fuels 33:1722-1733 (2018), which is hereby incorporated by reference in its entirety. Briefly, this pathway is based on initial findings that aqueous amines and amino acid-bearing solvents can capture CO.sub.2 via absorption. The captured CO.sub.2 in the aqueous phase reacts with the dissolved Ca-bearing species to precipitate CaCO.sub.3, while chemically regenerating the solvent. The feasibility of this coupled reaction pathway was evident from the near complete conversion of alkaline precursors such as CaO to CaCO.sub.3 at 50 C. with 30 wt % CO.sub.2-loaded monoethanolamine (MEA) and a slurry reaction environment comprising 15 wt % solid in 3 hours. Liu & Gadikota, Integrated CO.sub.2 Capture, Conversion, and Storage To Produce Calcium Carbonate Using an Amine Looping Strategy, Energy & Fuels 33:1722-1733 (2018), which is hereby incorporated by reference in its entirety.

[0199] Metastable phases such as aragonite and vaterite were co-present with stable phases such as calcite, and broader multi-modal particle size distributions were evident. This observed polymorphism and lack of morphological specificity challenge the use of these carbonates in real-world applications where single crystal phases with well-controlled morphologies are desired. The observed polymorphism is attributed to the non-uniform flow and concentration fields arising from mixing in batch reactor environments. Specifically, the concentration gradients and flow fields differ with distance from the impeller in a batch process. To address this challenge, achieving tunable controls on flow fields is essential. Prior work has established that consistent and controlled internal crystal structures and particle morphologies can be achieved by tuning vortex flows using Taylor-Couette (T-C) Crystallizers. Aljishi et al., Effect of Flow Structure at the Onset of Instability on Barium Sulfate Precipitation in Taylor-Couette Crystallizers, J. Cryst. Growth 373:20-31 (2013) and Nguyen et al., Multiple Feeding Strategy for Phase Transformation of GMP in Continuous Couette-Taylor Trystallizer, Cryst. Growth Des. 12:2780-2788 (2012), both of which are hereby incorporated by reference in their entirety. Briefly, T-C Crystallizers contain two concentric rotating cylinders with confined fluids. It has been scientifically proven that vortex flows arising from the onset of flow instabilities yield smaller unit cell dimensions with narrower and smaller crystal size distributions. Aljishi et al., Effect of Flow Structure at the Onset of Instability on Barium Sulfate Precipitation in Taylor-Couette Crystallizers, J. Cryst. Growth 373:20-31 (2013) and Nguyen et al., Multiple Feeding Strategy for Phase Transformation of GMP in Continuous Couette-Taylor Trystallizer, Cryst. Growth Des. 12:2780-2788 (2012), both of which are hereby incorporated by reference in their entirety. The feasibility of achieving tunable crystal structures and morphologies in barium sulfate crystals has been demonstrated. Aljishi et al., Effect of Flow Structure at the Onset of Instability on Barium Sulfate Precipitation in Taylor-Couette Crystallizers, J. Cryst. Growth 373:20-31 (2013), which is hereby incorporated by reference in its entirety. Coupling the use of T-C Crystallizers with the Aqueous Alkaline Amine Looping (A3L) pathways will allow for development of a device with tunable flow controls to synthesize CaCO.sub.3 with structural and morphological specificity while effectively regenerating the amine-bearing solvent (FIG. 34).

[0200] Extensive research efforts have led to the commercialization of CO.sub.2 capture technologies such as the use of amine-bearing solvents in commercial scale operations in the Petra Nova, Quest and Boundary Dam projects. Mission Innovation, Accelerating Breakthrough Innovation in Carbon Capture, Utilization, and Storage, Houston, Texas, 2017, which is hereby incorporated by reference in its entirety. CO.sub.2 capture and regeneration temperatures in these processes are 40-60 C. and 120-140 C., respectively. The captured CO.sub.2 is injected and stored in underground geologic formations. To convert, store and use CO.sub.2, Solidia Technologies has commercialized the use of CO.sub.2 to cure cement by reacting with calcium silicate to produce a carbonate shell which binds the sand grains. U.S. Pat. No. 8,114,367, which is hereby incorporated by reference in its entirety. Only partial conversion of the silicate to carbonate is achieved using this route and this technology is specific to the cement industry. To date, there are no devices that integrate CO.sub.2 capture with conversion and storage to produce carbonates with structural and morphological specificity and the inherent regeneration of the solvent media at a low temperature of 50 C. by harnessing internal flow controls and without additional unit operations. The aim is to establish a continuous scalable manufacturing system to produce calcium carbonate with morphological and structural specificity at temperatures in the range of 25-75 C. and time scales to the order of minutes as opposed to hours. A functioning prototype of a T-C Crystallizer is designed and adapted to achieve this aim.

[0201] Design of Taylor-Couette (T-C) CrystallizerA T-C Crystallizer is created to operate at temperatures in the range of 25 C.-75 C. The crystallizer with 100 ml volume is assembled and modified based on the previous design experiences. Temperature controls are newly equipped using the resistance heating mechanism. This crystallizer is designed to perform proof-of-principle tests with flow rates to the order of few ml/min and to produce calcium carbonate to the order of a few grams. The outcome is a prototype device to demonstrate proof-of-principle for accelerated CO.sub.2 conversion and storage as CaCO.sub.3.

[0202] Influence of aqueous chemistry and vortex flows on CaCO.sub.3 structure and morphologyThe influence of CO.sub.2-loaded aqueous amine compositions (e.g., 10-50 wt. % monoethanolamine (MEA) in water) and slurry compositions of CaO (range from 10-50 wt % in water) at temperatures in the range of 25 C.-75 C. on CaCO.sub.3 structure and morphology are investigated. Flow rates to the order of 50-100 ml/min are probed. As shown in FIG. 34, the inlet streams are not pre-mixed and instead enter through separate inlets. The influence of laminar and turbulent vortex flows on the structure and morphology of the carbonates are contrasted. The hypothesis that rapid mixing in the localized vortex flow fields reduces the unit cell dimensions and yields smaller and repeatable morphologies of calcium carbonates is tested. Cylinder rotation are varied from 100 rpm to 1,000 rpm representing laminar, vortex, and turbulent flows, respectively. The crystal structures of the carbonate-bearing products are determined using X-Ray Diffraction (XRD) and carbonate content using Thermogravimetric Analyses (TGA). BET measurements are performed for surface area and pore size analyses and the nano-scale morphologies are determined using Scanning and Transmission Electron Microscopy (SEM/TEM). XRD and SEM/TEM are available. TGA and BET measurements are performed. The results from these experiments are directly mapped to published data where batch reactor environments were used to investigate the efficacy of the aqueous alkaline amine looping process (Liu & Gadikota, Integrated CO.sub.2 Capture, Conversion, and Storage To Produce Calcium Carbonate Using an Amine Looping Strategy, Energy & Fuels 33:1722-1733 (2018), which is hereby incorporated by reference in its entirety) and CaCO.sub.3 supersaturation. The outcome is to quantify chemical and flow regime controls on the structural and morphological features of CaCO.sub.3.

[0203] Scale-up of Taylor-Couette (T-C) CrystallizerInsights into the residence times, flow regimes and aqueous chemical compositions yielding stable CaCO.sub.3 phases obtained are used to modify and test a scaled-up version of the T-C Crystallizer. The large scale T-C system is modified to handle flow rates to the order of 1 liter per min of solutions bearing CaCO.sub.3. Scaling relationships are used to determine the flow velocities yielding turbulent and localized vortex flows to achieve the desired crystalline habits and particle sizes. The optimal aqueous chemical compositions identified will be considered when designing this system. The outcome is a bench-scale design of T-C Crystallizer optimized for CaCO.sub.3 structure and morphology.

[0204] While the novel technology has been illustrated and described in detail in the figures and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only the preferred embodiments have been shown and described and that all changes and modifications that come within the spirit of the novel technology are desired to be protected. As well, while the novel technology was illustrated using specific examples, theoretical arguments, accounts, and illustrations, these illustrations and the accompanying discussion should by no means be interpreted as limiting the technology. All patents, patent applications, and references to texts, scientific treatises, publications, and the like referenced in this application are incorporated herein by reference in their entirety.

[0205] Although preferred embodiments have been depicted and described in detail herein, it will be apparent to those skilled in the relevant art that various modifications, additions, substitutions, and the like can be made without departing from the spirit of the invention and these are therefore considered to be within the scope of the invention as defined in the claims which follow.