RARE EARTH ELEMENT EXTRACTION METHODS AND APPARATUSES
20260103778 ยท 2026-04-16
Assignee
Inventors
- Charles Agee Atkins (Sheridan, WY, US)
- Garrett W. Lindemann (Buffalo, WY, US)
- Donald W. Collins (Santa Clarita, CA, US)
- Charles Hill (Sheridan, WY, US)
- Alex Moyes (Chester, VA, US)
Cpc classification
C22B3/08
CHEMISTRY; METALLURGY
C22B3/22
CHEMISTRY; METALLURGY
International classification
C22B3/08
CHEMISTRY; METALLURGY
C22B3/20
CHEMISTRY; METALLURGY
C22B3/22
CHEMISTRY; METALLURGY
Abstract
A method of extracting a rare earth element from a carbonaceous material deposit utilizing a ligand to capture the rare earth element includes crushing the carbonaceous material deposit to form a carbonaceous material particulate and forming a first pregnant leachate including the carbonaceous material particulate and a ligand. The method further includes extracting the metal impurities via an ion exchange or floatation to form a reduced leachate and forming a second pregnant leachate comprising the reduced leachate and the ligand. The method also includes extracting the rare earth element from the reduced leachate via an ion exchange or floatation, capturing the rare earth element in the binding site of the ligand, and desorbing the rare earth element from the ligand.
Claims
1. A method of separating rare earth elements from a feedstock of carbonaceous material, the method comprising: separating gallium and germanium from the feedstock; separating the feedstock into a first solution comprising light rare earth elements, a second solution comprising middle rare earth elements, and a third solution comprising heavy rare earth elements; and separating individual rare earth elements from each of the first solution, the second solution, and the third solution.
2. The method of claim 1, wherein the individual rare earth elements are separated by capture by lanmodulin.
3. The method of claim 2, further comprising releasing the individual rare earth elements by altering a pH of a solution comprising the individual rare earth elements and the lanmodulin.
4. The method of claim 2, further comprising releasing the individual rare earth elements by electrically stimulating a solution comprising the individual rare earth elements and the lanmodulin.
5. The method of claim 1, wherein the gallium and germanium are separated from the feedstock by a precipitation reaction.
6. The method of claim 1, wherein the gallium and germanium are separated from the feedstock by an acid leaching and filtration separation.
7. The method of claim 1, wherein the light rare earth elements, the middle rare earth elements, and the heavy rare earth elements are separated by capture by lanmodulin.
8. The method of claim 7, wherein the feedstock is separated into the first solution, the second solution, and the third solution by altering a pH of the feedstock to selectively release the light rare earth elements, the middle rare earth elements, and the heavy rare earth elements.
9. A method of functionalizing carbon fiber for capturing rare earth elements, the method comprising: providing a carbon substrate; providing a metal-binding biological ligand comprising a linker; and attaching the metal-binding biological ligand through the linker by a single chemical reaction.
10. The method of claim 9, further comprising capturing rare earth elements by the metal-binding biological ligand in a fluidized bed reactor.
11. The method of claim 9, further comprising capturing rare earth elements by the metal-binding biological ligand in a membrane separation system.
12. The method of claim 9, further comprising electrically stimulating the carbon substrate to selectively absorb or desorb specific rare earth elements from the metal-binding biological ligand.
13. The method of claim 9, wherein the metal-binding biological ligand is configured to capture a rare earth element at a first pH and release the rare earth element at a second pH different form the first pH.
14. The method of claim 9, wherein the metal-binding biological ligand comprises lanmodulin.
15. A system for extracting rare earth elements comprising: a first separator for removing aluminum, gallium, and germanium from an inlet stream; and a second separator comprising a filter for capturing the rare earth elements, the filter comprising: a carbon substrate; and a glycolipid coupled to the carbon substrate, the glycolipid comprising a binding site configured to capture the rare earth elements.
16. The system of claim 15, wherein the first reactor comprises an alkali leaching and filtration separator.
17. The system of claim 15, wherein the second reactor comprises a fluidized bed separator or a filtration separator.
18. The system of claim 15, wherein the glycolipid is configured to capture a range of rare earth elements and selectively release rare earth elements at selected pH.
19. The system of claim 15, wherein the glycolipid is configured to capture a specific rare earth element.
20. The system of claim 15, further comprising a third separator for removing iron and impurities from the inlet stream.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] The disclosure will be readily understood by the following detailed description in conjunction with the accompanying drawings, wherein like reference numerals designate like structural elements, and in which:
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[0039] Throughout the drawings, identical reference numbers designate similar, but not necessarily identical, elements.
DETAILED DESCRIPTION
[0040] Reference will now be made in detail to representative embodiments illustrated in the accompanying drawings. It should be understood that the following descriptions are not intended to limit the embodiments to one preferred embodiment. To the contrary, it is intended to cover alternatives, modifications, and equivalents as can be included within the spirit and scope of the described embodiments as defined by the appended claims.
[0041] As described below, rare earth elements and advanced carbon materials, such as carbon fibers can be produced from raw, mined carbonaceous materials. The carbonaceous materials can include, for example, coal and clay ores and carbon-related deposits, which can also broadly be referred to as carbonaceous ores. The present description provides examples, and is not limiting of the scope, applicability, or configuration set forth in the claims. Thus, it will be understood that changes can be made in the function and arrangement of elements discussed without departing from the spirit and scope of the disclosure, and various embodiments can omit, substitute, or add other procedures or components, as appropriate. For instance, methods described can be performed in an order different from that described, and various steps can be added, omitted, or combined. Also, features described with respect to some embodiments can be combined in other embodiments.
[0042] Rare earths are a group of elements, like neodymium, praseodymium, and scandium. Rare earths are used in a wide array of applications. In this disclosure, rare earth elements can include the fifteen lanthanides on the periodic table plus scandium and yttrium and can also refer to gallium and germanium herein. Rare-earth elements (REE) are important components of several products across a wide range of applications, especially high-tech consumer products, such as cellular telephones, computer hard drives, electric and hybrid vehicles, and flat-screen monitors and televisions. Significant defense applications include electronic displays, guidance systems, lasers, and radar and sonar systems. Although the amount of REE used in a product may not be a significant part of that product by weight, value, or volume, the REE can be important for the device to function.
[0043] On average, the REE content in carbonaceous materials and/or carbonaceous material ash can be about up to about 30%. The REE can be recovered and upgraded from the carbonaceous materials. Direct coal liquefaction (DCL) involves contacting coal directly with a catalyst at elevated temperatures and pressures with added hydrogen (H.sub.2), in the presence of a solvent to form a raw liquid product which can be filtered or processed to extract the REE and further refined into products such as liquid fuels. DCL is termed direct because the coal is transformed into liquid without first being gasified to form syngas (which can then in turn be transformed into liquid products). The latter two-step approach, i.e. the coal-to-syngas-to-liquids route is termed indirect coal liquefaction (ICL). Therefore, the DCL process is, in principle, the simpler and more efficient of the two processes. DCL can, however, use an external source of H.sub.2, which may have to be provided by gasifying additional coal feed, biomass, and/or the heavy residue produced from the DCL reactor. The DCL process results in a relatively wide hydrocarbon product range including a variety of molecular weights and forms, with aromatics dominating. Accordingly, the product can undergo substantial upgrading to yield desirable products.
[0044] The DCL process can involve adding hydrogen (hydrogenation) to the coal, breaking down the organic structure of the coal into soluble products. The reaction in DCL is conducted at elevated temperature and pressure (e.g., 750 F. to 850 F. (about 399 C. to about 454 C.) and 1,000 to 2,500 psia) in the presence of a solvent. The solvent is used to facilitate coal extraction and the addition of hydrogen. The solubilized products, including mainly aromatic compounds, may then be upgraded by conventional petroleum refining techniques, such as hydrotreating, to meet final liquid product specifications.
[0045] Although DCL and ICL have been described in the context of liquefaction of coal, similar processes can be used in the liquefaction of other carbonaceous materials. The systems and methods herein can include liquefying a carbonaceous material to form a carbonaceous tar pitch and removing REEs from the pitch. The carbonaceous tar pitch can be thermally treated to a liquid crystal phase exhibiting anisotropic spheres of mesophase and further spun to form carbon fibers. In some examples, the pitch (e.g., a liquified carbonaceous material and mineral solution) can be fed into an electric swing adsorption apparatus (e.g., or an electrothermal swing adsorption apparatus) wherein the REEs can be absorbed with a carbon monolith (e.g., that can be functionalized with chelating ligands, such as metal-binding biological ligands).
[0046] These and other examples are discussed below with reference to
[0047] According to some embodiments, and as illustrated in
[0048] In some embodiments, the act 102 of subjecting a raw carbonaceous material to a liquefaction process to form a pitch or a pitch resin can include contacting an amount of carbonaceous material directly with a catalyst in the presence of a solvent, exerting a predetermined pressure of about 1000 pounds per square inch absolute (psia) or less on the amount of carbonaceous material and the solvent, heating the amount of carbonaceous material and the solvent to a predetermined temperature of about 380 C. or less, and liquefying at least some of the amount of carbonaceous material to form a carbonaceous tar pitch. In some examples, the carbonaceous materials can comprise anthracite coal and/or coal extracted from Wyoming's Powder River Basin. The carbonaceous materials can include other carbonaceous materials extracted from Wyoming's Powder River Basin or other sources. The catalyst may include any catalyst described herein or known in the art, and the solvent may include any solvent described herein or known in the art. In some examples, the catalyst can be but is in no way limited to a Lewis acid catalyst. In some examples, the solvent can include one or more of N-Methyl-2-pyrrolidone (NMP), quinoline, Fluorinert FC-71, silicone oils, phthalates such as dioctyl phthalate, SYLTHERM 800, acidic amine ionic liquid or any other suitable solvent or carrier. Examples of additional solvents that can be used can be found in John W. Freiderich et al., Dissolution of the Rare-Earth Mineral Bastnaesite by Acidic Amide Ionic Liquid for Recovery of Critical Materials, Chemistry Europe (Aug. 19, 2015), https://chemistry-europe.onlinelibrary.wiley.com/doi/10.1002/ejic.201500509, Gawen R. T. Jenkin et al., The application of deep eutectic solvent ionic liquids for environmentally-friendly dissolution and recovery of precious metals, ScienceDirect (Mar. 1, 2016), https://www.sciencedirect.com/science/article/pii/S0892687515300960?via%3Dihub, and Xiaohua Li & Koen Binnemans, Oxidative Dissolution of Metals in Organic Solvents, ACS Publications (Mar. 16 2021), https://pubs.acs.org/doi/10.1021/acs.chemrev.0c00917, which are incorporated herein by reference in their entireties.
[0049] In some examples, the act 102 can include pressurizing the carbonaceous material to a predetermined pressure (e.g., about 975 psia or less, about 950 psia or less, about 925 psia or less, about 900 psia or less, about 875 psia or less, about 850 psia or less, about 825 psia or less, about 800 psia or less, about 775 psia or less, about 750 psia or less, about 725 psia or less, about 700 psia or less, about 675 psia or less, about 650 psia or less, about 625 psia or less, about 600 psia or less, about 575 psia or less, about 550 psia or less, about 525 psia or less, about 500 psia or less, about 475 psia or less, about 450 psia or less, about 425 psia or less, about 400 psia or less, about 375 psia or less, about 350 psia or less, about 350 psia to about 450 psia, about 400 psia to about 500 psia, about 450 psia to about 550 psia, about 500 psia to about 600 psia, about 550 psia to about 650 psia, about 600 psia to about 700 psia, about 650 psia to about 750 psia, about 700 psia to about 800 psia, about 750 psia to about 850 psia, about 800 psia to about 900 psia, about 850 psia to about 950 psia). The carbonaceous material can be simultaneously heated to a predetermined temperature (e.g., about 380 C. or less, about 375 C. or less, about 370 C. or less, about 365 C. or less, about 360 C. or less, about 355 C. or less, about 350 C. or less, about 325 C. or less, about 320 C. or less, about 315 C. or less, about 310 C. or less, about 305 C. or less, about 300 C. or less, about 295 C. or less, about 290 C. or less, about 285 C. or less, about 280 C. or less, about 275 C. or less, about 270 C. or less, about 265 C. or less, about 260 C. or less, about 255 C. or less, 250 C. or less). The carbonaceous material can also be contacted directly with the catalyst in the presence of the solvent. Added hydrogen can also be contacted directly with the carbonaceous material. As noted above, the raw carbonaceous material can include an amount of REEs therein. In some examples, the carbonaceous material can include about 400 ppm of the REEs.
[0050] Act 104 of the method 100 of separating a rare earth element from carbonaceous material includes filtering the pitch or pitch resin (e.g., resulting from the act 102) to capture the rare earth element. In some embodiments, the filter can include a carbon fiber filter. However other filter types can be included. In some examples, the filter can include a nylon filter, a fabric filter, membrane systems, mechanical collectors, wet scrubbers, and electrostatic precipitators. In some examples the filter can provide filtrate quality of less than 0.3-0.5 parts per million (ppm) for particles as small as 0.5-1 m. In some examples, the filter can be less than 100 microns. In some embodiments, the filter can be less than 80 microns. For example, the REE may exhibit a diameter that is about 5 m or less, about 10 m or less, about 20 m or less, about 30 m or less, about 50 m or less, about 60 m or less, about 70 m or less, or in ranges of about 5 m to about 15 m, about 10 m to about 20 m, about 15 m to about 25 m, about 20 m to about 30 m, about 25 m to about 35 m, about 30 m to about 40 m, about 35 m to about 45 m, about 40 m to about 50 m, about 45 m to about 60 m, about 50 m to about 70 m, about 60 m to about 80 m, about 70 m to about 90 m, or about 80 m to about 100 m.
[0051] In some examples, the pitch or pitch resin can include an isotropic pitch. Isotropic pitch is amorphous, and the carbon fiber produced therefrom is low in strength. As such, anisotropic pitch is generally used for producing high strength and high elastic carbon fiber. Physical properties and composition of isotropic pitch are important for producing high strength and high elastic carbon fibers. In particular, high-strength carbon fibers may be manufactured by melting the isotropic pitch for producing carbon fibers having a certain range and level of molecular weight, softening point, and viscosity.
[0052] In some examples, the method 100 can include an act 106 that includes sorting the rare earth element. REEs with atomic numbers 57 to 63 are considered light REEs (LREEs), while those with atomic numbers 64 to 71 are considered heavy REEs (HREEs). The difficulty of separating and purifying the rare earth elements makes their production extremely expensive. For the rare earth elements, the outermost electron shell is filled the same way, causing these elements to react in similar ways. The similar reactivity makes it difficult to separate each of the REEs from one another. In some examples, act 106 can include a solvent extraction. Solvent extracting can include mixing various acids that have affinities for different rare earth elements and then allowing these mixtures to settle to gradually achieve higher concentrations of specific REE metals in each separation. In some examples, the solvent extraction can achieve purities higher than 99.9%. In some examples, ligands can be used to separate the REEs. In some examples, ion exchange and precipitation can be used for recovery of REEs from pregnant leach solutions obtained from acid leaching.
[0053] In one or all examples, the act 106 can sort the REEs into light rare earth elements (LREEs), middle rare earth elements (MREEs), and heavy rare earth elements (HREEs). The LREEs can include elements from lanthanum (La, atomic number 57) to neodymium (Nd, atomic number 60), the MREEs can include elements from promethium (Pr, atomic number 61) to dysprosium (Dy, atomic number 66), and the HREEs can include elements from holmium (Ho, atomic number 67) to lutetium (Lu, atomic number 71). The LREEs can further include scandium (Sc, atomic number 21). The HREEs can further include yttrium (Y, atomic number 39). In one or all examples, the REEs can be sorted differently, or the boundaries between groups of the REEs can be defined differently. Once the REEs are sorted into LREEs, MREEs, and HREEs, the REEs can be further sorted into each specific REE. This can be accomplished through capture by ligands attached to carbon substrates (e.g., activated carbon fiber modules, fused monolithic carbon fiber, other forms of carbon fiber, or the like). The ligands can capture specific REEs, and these REEs can be subsequently released from the ligands by altering the pH of a solution including the ligands. The ligands can be designed to capture one or more specific REEs or other elements (e.g., germanium (Ge), gallium (Ga), or the like). Each element can be released from the ligands by adjusting the pH of a solution including the ligands to a specific value. In some examples, the ligands can include organic compounds or functional groups that form complexes with REE ions and/or metal ions. For example, the ligands can include multi-dentate carboxylate complexing units, described in Subhamay Pramanik et al., Emerging Rare Earth Element Separation Technologies, Chemistry Europe (Jun. 21, 2025), https://chemistry-europe.onlinelibrary.wiley.com/doi/10.1002/ejic.202400064, which is incorporated herein by reference in its entirety. Examples of functionalization of carbon substrates that can be used can be found in Feiping Zhao, Selectively capacitive recovery of rare earth elements from aqueous solution onto Lewis base sites of pyrrolic-N doped activated carbon electrodes, ScienceDirect (September 2022), https://www.sciencedirect.com/science/article/abs/pii/S0008622322004729?via % 3Dihub and Omar A. Kazi et al., Material Design Strategies for Recovery of Critical Resources from Water, National Library of Medicine (Jul. 19, 2023), https://pubmed.ncbi.nlm.nih.gov/37000538/, which are incorporated herein by reference in their entireties.
[0054] In some examples, the act 106 can be performed using an activated carbon fiber monolith with ligands that can be electrically stimulated to adjust the binding, adsorption, and unbinding of REEs or other metals to and from the ligands. The activated carbon fiber monolith can be a relatively conductive material, which can allow the ligands to be electrically stimulated. The ligands can react to electrical potential (e.g., through the activated carbon monolith) to effect the size selection and binding energy of specific REE ions or other metal ions. By using conductive activated carbon fiber material substrates, electrical potential can be selectively supplied to the ligands to alter how the ligands bind, unbind, and adsorb various ions.
[0055] In some examples, the activated carbon fiber monolith (ACFM) can be used as a flow electrode in capacitive deionization. The ACFM can be an optimized electrode. By functionalizing the ACFM, selective migration of REE and other metal ions from a low-concentration carbonaceous liquid solution (e.g., a coal liquid and dissolved mineral solution) to a concentrated stream or isolated stream of purified REE ions, metal ions, or groups of REE and/or metal ions can be enabled. Changyong Zhang et al., Flow Electrode Capacitive Deionization (FCDI): Recent Developments, Environmental Applications, and Future Perspectives, Environ. Sci. Technol. (Mar. 16, 2021), 55, 4243-4267 and Minlin Mao et al., Selective Capacitive Recovery of Rare-Earth Ions from Wastewater over Phosphorus-Modified TiO2 Cathodes via an Electro-Adsorption Process, ACS Publications (Jul. 23, 2025), https://pubs.acs.org/doi/10.1021/acs.est.4c03241, provide examples of capacitive deionization and are incorporated herein by reference in their entireties.
[0056] In some examples, the ACFM can include two or more different ligands. The ACFM can include a primary ligand and a secondary ligand. The primary ligand can be the more abundant ligand and the secondary ligand can be the less abundant ligand. The AFCM can be stimulated in order to adjust binding, unbinding, and adsorption by both the primary ligand and the secondary ligand to selectively bind, adsorb, and unbind REE and metal ions to both the primary and secondary ligands. The stimulation can include electrical stimulation, pH stimulation, temperature stimulation, and the like, all of which can be used to alter binding, adsorption, and unbinding of REEs and metal ions from both the primary and secondary ligands.
[0057] Ligands can be attached to various carbon substrates in order to extract REEs and metal ions, as described in the present disclosure. The carbon substrates can include, for example, carbon, nano-carbon (e.g., synthesized from Anthracite coal or other carbonaceous materials), fine carbon, carbon graphene balls (e.g., 3D, hollow, from coke and coal gas, or from other carbonaceous materials), interconnected graphene capsules (e.g., coal tar pitch or carbonaceous tar pitch), coal and water, coal in vacuum, amorphous carbon, hot carbonized coal or carbonaceous materials (e.g., to a temperature of about 650 C. or greater), coal char after pyrolysis or other carbonaceous char after pyrolysis (e.g., to a temperature of about 800 C. or greater), activated carbon, coal pitch (e.g., carbonaceous pitch or graphitized carbon foam), carbon fiber (e.g., carbonized at high temperatures such as in a range from about 1,800 to about 2,200 C.), activated carbon fiber felt, activated carbon fiber cloth wrap, activated carbon fiber cloth fill, activated carbon fiber monolith, natural graphite, synthetic graphite, single layer graphene, graphene nanoplatelets, grapheme quantum dots (e.g., synthesized from Bituminous coal or other carbonaceous materials), grapheme sheets (e.g., synthesized from Anthracite coal or other carbonaceous materials), nanosheets and grapheme quantum dots (e.g., synthesized from Bituminous coal or other carbonaceous materials), carbon nanotubes, multiwall carbon nanotubes, 3D graphene, diamond, tar, low-volatile Bituminous (LVB) coal, and/or mesophase materials. The carbon substrates can have the following electrical properties:
TABLE-US-00001 TABLE 1 Electrical Properties of Carbon Substrates Electrical Electron Specific Energy Capacitance Substrate Conductivity Resistance Resistivity Mobility Capacitance Density retention Carbon 3.5 10.sup.5 Ohm/m [1] Nano-Carbon 65.4 Farads/ (200 cycles) (Synthesized gram [2] from Anthracite Coal) Fine Carbon 8.5 to 9.0 Ohm/m [3] Carbon graphene 321 Farads/ ~94% balls (3D, gram [2] (1,000 hollow, from cycles) coke & coal gas) Interconnected 277 Farads/ 97% graphene gram [2] (15,000) capsules (coal tar pitch) Coal + water 10.sup.3 S/m 7-20 m (tunable Ohm/m over 7 Magnitudes of Order) [4] Coal at 110 10.sup.8 S/m 7-20 m C. + Vacuum Ohm/m Carbon 1.25 to 2 5 to 8 (Amorphous) 10.sup.3 S/m [2] 10.sup.4 Ohm/m [2] Hot Carbonized 7-20 m Coal (above Ohm/m 6500 C.) Coal Char 10.sup.2 S/m 7-20 m after pyrolysis Ohm/m to 8000 C.+ Coal Pitch 126.6 S/m (graphitized carbon foam) Carbon Fiber - 7.58 10.sup.3 S/m carbonization at high Temperatures as high as 1,800-2,2000 C. ACF Felt 1 [5] 221 Ohms 132.6 Ohm/m ACF Felt 2 694 Ohms 277.6 Ohm/m ACF Cloth Wrap 839 Ohms 83.9 Ohm/m ACF Cloth Fill 1,147 Ohms 144.7 Ohm/m Ramaco ACFM 176 Ohms 1.17 Ohm/m Natural In-plane 2 to In-plane Graphite 3 10.sup.5 S/m 3.0 10.sup.3 Through- Through plane 3.3 Plane 3.3 10.sup.2 [6] 10.sup.3 [4] Single Layer 6 10.sup.6 S/m 1 10.sup.6 >10,000 ~21 F/cm.sup.2 232.6 to Near 100% Graphene at Ohms/m cm.sup.2/Vs (135 to 2585 226 Wh/Kg Room Temperature Farads/gm) Graphene Through Nanoplatelets Plane 10.sup.2 S/m & In-plane ~10.sup.7 S/m Graphene Quantum 230 Farads/ 10 A/gram (10,000 Dots (source gram [2] Cycles) bituminous coal) Graphene sheets 200 Farads/ 50 mA/gram (1,000 (source gram [2] Cycles) graphitized anthracite coal) Nanosheets + 388 Farads/ (1,000 Graphene gram [2] Cycles) Quantum Dots (source bituminous coal) Graphene 7.67 mOhm/m 277 Farads/gram 10 Ma/gram 91% Nanostrips (2,000 (graphene sheets) Cycles) Multiwall 10.sup.3 to 10.sup.4 Carbon S/cm [1] Nanotubes 3D Graphene 182.6 Farads/gm >10 Wh/Kg ~80% (NETL) Diamond ~10.sup.13 1 10.sup.12 S/m [2] Ohms/m [2] [1] Cutnell and Johnson, Physics 4th Ed. New York, Wiley, Resistivity of Various Materials. [2] Thomas and Manoj Int. J. Coal Sci. Technol. (2021) Electrochemical Efficacies of coal derived nanocarbons Vol. 8 (4): 459-472 [3] Tokai Carbon Company (2003) Products Fine Carbon. [4] Zang, Dong, Jian, Ferralis, and Grossman (2022) Cell Press Matter Upgrading carbonaceous materials: Coal, tar, Pitch, and beyond. Vol 5, p 430-447. [5] Charles Hill (RAMACO), and Frederic Vautard (ORNL) Ramaco Research Rodeo (R3) 4.0, Jul. 9-11, 2024. Activated Carbon Fiber Monoliths For Industrial Decarbonization. [6] Table of Electrical Resistivity and conductivity, Science, Tech, Math > Science
[0058] Additionally, the carbon substrates can include laser-ablated heavy hydrocarbons, as described in Zang, Dong, Jian, Ferralis, and Grossman, CellPress Matter, Upgrading carbonaceous materials: Coal, tar, pitch, and beyond (2022) Vol 5, 430-447, which is incorporated herein by reference in its entirety, and which electrical properties are illustrated in
[0059] In some examples, the carbon substrates can include gasified coal, as described in Duba, A. G. Fuel (1977) Vol 56, October, Electrical conductivity of coal and coal char, which is incorporated herein by reference in its entirety, and which electrical properties are illustrated in
[0060] In some examples, the method 100 can include the act 108 of refining the pitch or pitch resin to produce a mesophase pitch. In some examples, the method includes thermally treating the carbonaceous tar pitch to a liquid crystal phase exhibiting anisotropic spheres of a mesophase pitch. Mesophase pitch has a heterogeneous structure including anisotropic regions. Several spinning modes such as centrifugal spinning, jet spinning, and conventional melt spinning have been used to spin mesophase pitches. Mesophase pitch is a precursor to mid and high-performance carbon fibers, highly conductive carbon foams and other advanced carbon materials. Large highly aromatic molecules stack to form liquid crystalline domains that can be aligned by different processing methods to produce highly ordered crystalline materials. These highly ordered crystalline materials can have high strength and modulus with efficient electrical and thermal conductivity. In some examples, the act 108 can include a hydrogenation to make mesophase pitch. In some examples, mesophase pitch can be prepared with sulfur as a crosslinking agent. The effect of the crosslinking agent depends on the swelling degree of styrene-butadiene-styrene (SBS, e.g., with antimony sulfur as a crosslinking agent) to some extent. Due to the crosslinking reaction, a crosslinked polymer network can be formed in mesophase pitch.
[0061] In some examples, the method 100 can include the act 110 of subjecting the mesophase pitch or pitch resin to a low-crystallinity spinning process to form a carbon fiber. The post-treatment conditions and structure of mesophase pitch determine the performance and structure of the prepared carbon materials which includes carbon fibers. In addition to its low density, high modulus, high strength, carbon fiber also has the resistance to deformation and high temperature, small coefficient of thermal expansion, good mechanical properties as well as thermal and electrical conductivity. Carbon fiber materials can be used as both structural and functional materials. High-performance carbon fiber bears high specific modulus and strength. The density of high-quality carbon fiber is about 25% of that of steel wire while the tensile strength can reach 3 times that of steel wire, and the tensile modulus can even reach 5 times that of steel wire, which is the best material among high-performance fiber materials.
[0062] After the desired mesophase pitch has been prepared, it is spun into fibers by conventional techniques, e.g., by melt spinning, centrifugal spinning, blow spinning, or in any other known manner. As noted above, in order to obtain highly oriented carbonaceous fibers capable of being heat treated to produce carbon fibers having a high Young's modulus of elasticity and high tensile strength, the pitch can, under quiescent conditions, form a homogeneous bulk mesophase having large, coalesced domains, and be nonthixotropic under the conditions employed in the spinning.
[0063] The temperature at which the pitch is spun depends of course, upon the temperature at which the pitch exhibits a suitable viscosity. Pitches containing a mesophase content of about 40 percent by weight can have a viscosity of about 200 poise at about 300 C. and about 10 poise at about 375 C. Pitches containing a mesophase content of about 90 percent by weight exhibit similar viscosities at temperatures above 430 C. Within this viscosity range, fibers can be spun from the pitch. Preferably, the pitch can have a mesophase content of from about 50 percent by weight to about 65 percent by weight and exhibit a viscosity of from about 30 poise to about 150 poise at temperatures of from about 340 C. to about 380 C. At such viscosity and temperature, uniform fibers having diameters of from about 5 microns to about 25 microns can be spun.
[0064] In some examples, the method 100 can include an act 112 of modifying a carbon fiber filter to bind or electrostatically interact with a rare earth element. For example, modifying the carbon fiber to bind or electrostatically interact with the rare earth element can include attaching a mineral binding protein or a lanthanide binding protein to the carbon fiber. In general, any metal binding protein could be altered to bind REEs or any other critical metal for harvesting metals from a solution. For example, methylotrophic bacteria can utilize lanthanides for binding REEs. Lanmodulin (LanM) includes 3 binding sites. LanM forms highly stable and water-soluble complexes across the REE series while retaining a selectivity against non-REE elements. LanM is a conserved protein across many species of methylotrophic bacteria. LanM enables a one-step, quantitative extraction, and purification of REEs from a pitch feedstock, including pre-combustion carbonaceous materials. In some examples, the similarity in affinity between REEs can be leveraged to recover total and multiple types of REEs against non-REE elements. In some examples, other proteins such as Tf, Scn, and CaM can also exhibit affinities toward REEs and could also be used for REE separation.
[0065] In some examples, the act 112 can include using a bacterium to express and display proteins that can capture the REE. One combination of bacteria and proteins displays the REE binding proteins upon the surface of bacteria. In some examples, the bacteria can co-express a metal binding protein and a protein to bind to a support such as an antibody to bind biotin or another hapten or one part of the streptavidin-avidin binding system. Some embodiments can include proteins displayed upon yeast, mammalian cells, and viruses as well as bound to columns or solid supports for testing, selection, and commercial application to capture and speciate REEs and other critical minerals. In some examples, mammalian cells can function as platforms for display as well as expression. The mammalian cells may offer the advantage of binding of specific materials vs bacteria. For expression of proteins, the mammalian cells should be best at expression and production of proteins especially in a continuous hollow fiber system. The protein can be configured to capture the REE from a solution. An example of the REE, critical mineral, and/or precious metals containing solutions are pregnant lixiviants produced by the leaching of ores, heaps, tailing piles, in situ mining, or recycled computer or battery material (e.g., lithium black mass). Similar to above, the REE protein displayed is one of the lanmodulin proteins that specifically and tightly bind REEs.
[0066] One form of this protein is a monomer with four (4) binding sites, the other is a dimer protein with 4 binding sites. The differences between the two proteins, other than size, are the binding affinities for REEs and the ability to differentiate between pairs of REEs allowing increased speciation of the elements. In some examples, the metal binding sites can be changed or altered to bind any other metal. The display of proteins on bacteria decreases the degradation of the protein and increases the life space and activity of the displayed protein. In some examples, the bacteria can be killed and freeze-dried for transportation and the bacteria with the displayed protein can be rehydrated when desired for REE extraction.
[0067] In some examples, the combination of protein and display system (e.g., bacteria, yeast, mammalian cells, and/or viruses) can be subjected to selection forces (either positive or negative, or combinations of both), to identify populations of phage, bacteria, yeast, virus, or mammalian cells that display proteins that bind the REE or mineral or demonstrate some improved function such as speciation and/or selectivity of REEs or other critical minerals.
[0068] In some examples, the act 112 can include expanding and subjecting a selected population of combinations to either the same selection or a different selection and/or improved binding affinity or affinities. In other words, a few to several rounds of the selection can be applied until the desired characteristic has been identified. In some examples, the protein with the desire characteristics can then be transferred to another display technology for addition selection or can be transformed into a cellular or viral expression system for either display and/or usage to bind REEs or minerals for expression and attachment to column material or a carbon fiber.
[0069] In some examples, act 112 can include breaking up a REE or mineral binding proteins into a fragment display library and then selecting from the library proteins that bind the desired REE or mineral or has the desired characteristic such as increased REE or critical mineral binding affinities, improved speciation, increased life span, etc. In some examples, the display libraries can be made by randomly breaking up a protein's coding portion of the REE binding proteins and inserting the fragments back into an expression vector for expression in a host and selection. For example, break-up of the REE and mineral binding expression clones can be by a non-limiting list of DNA shearing, Restriction Enzyme slicing, random DNA amplicon production, codon bias changes, protein sequence amino acid changes, CRISPER, and other technologies.
[0070] In some examples, the display technologies are used to screen REE and mineral binding proteins that have been subjected to methods that have caused changes in the DNA that then result in changes in the amino acid sequence and the activities and characteristics of the REE and mineral binding proteins. These DNA changing technologies include CRISPER, recombinant technologies for insertion or removal of a sequence, or amino acid, and other mutation inducing processes.
[0071] In some examples, act 112 can further include blocking the bacteria protein display system, or specifically blocking non-specific binding sites to prevent the reduction of the percentage of REEs in solution being captured by the protein. For example, blocking non-specific binding sites can be desirable because a portion of the REEs and/or critical minerals will interact with the surface of the bacteria and not be captured by the protein. Therefore, when the system (e.g., bacteria expressing REE capture proteins) is washed prior to a release of the REEs, the REEs not captured would be eluted and washed out of the system. That eluate would require re-exposure to the system or exposure to a different system to recover the REEs that were washed out. For example, a blocking compound can include in situ hybridization blockers including powdered milk, hydrolyzed milk proteins, hydrolyzed bovine serum albumin, sheared salmon sperm, or a combination thereof.
[0072] In some examples, the act 112 of modifying the carbon fiber to bind or electrostatically interact with the rare earth element can include increasing a negative charge of the carbon fiber to increase an electrostatic interaction with the rare earth element. In some examples, the carbon fiber can be functionalized to introduce magnetic or electric field properties, such as magnetite (Fe.sub.3O.sub.4) or phosphorous-modified titanium oxide (TiO.sub.2) (as described in Shanshan Tong et al., Modification of multi-walled carbon nanotubes with tannic acid for the adsorption of La, Tb and Lu ions, Springer Nature Link (May 24, 2011), https://link.springer.com/article/10.1007/s00604-011-0622-3, which is incorporated herein by reference in its entirety) into the fiber with the purpose of affording magnetic properties to the material. As described throughout the present disclosure, the carbon fiber can be functionalized to include good electrical conductivity properties, which can then be used to electrically stimulate ligands attached to the carbon fiber. In some examples, the carbon fiber can be functionalized to introduce chitosan to increase the maximum adsorption capacity of the material. In some examples, the functionalization can be achieved through the preparation of nanostructured silica-coated magnetite, followed by coating with the proposed functions. The resulting material tends to display higher sorption capacity of REEs and magnetic properties that simplify the separation process of the material in aqueous media.
[0073] In one or all examples, the act 112 can include attaching ligands to a carbon substrate (e.g., activated carbon fiber modules, fused monolithic carbon fiber, other forms of carbon fiber, or the like). The ligands can include glycolipids, which can have binding sites for specific REEs. The ligands can include other lipids that can include binding sites for REEs or other metals. The ligands can be attached to the carbon fiber using a single reaction. The ligands can be or include lanmodulin-based proteins (LanM) or other metal-binding proteins. The ligands can generally include biological ligands with binding sites for metals (e.g., metal-binding biological ligands). The ligands can include a linker, which can bind to the carbon substrates. The carbon substrates and attached ligands can be used in packed bed reactors, fluidized bed reactors, or the like.
[0074]
[0075] The carbonaceous materials for the source 202 can then be sized for processing in a crusher 204. In some examples, the ore crusher pulverizes a raw ore into an ore particle. In some examples, the system 200 can include an ore crusher that pulverizes a raw ore into an ore particle comprising a diameter between about 1 mm and about 1 cm. In some examples, these particles can be crushed to include diameters less than 1 mm. In some examples, the particles can include diameters less than 1 m, less than 10 m, less than 50 m, less than 200 m, or less than 600 m. In some examples the particles crushed can include a particle size in ranges between about 1 m and about 1 mm. Other ranges can include between about 1 m and about 10 m, between about 10 m and about 50 m, between about 50 m and about 250 m, between about 250 m and about 500 m, between about 500 m and about 1 mm, between about 1 mm and about 200 mm, between about 200 mm and about 500 mm, or between about 500 mm and about 1 cm.
[0076] In some examples, after sizing, water can be removed from the carbonaceous materials in a dewatering system 206. Dewatering methods include both mechanical dewatering and geotube dewatering. In mechanical dewatering, crushed ore having a high-water content is sent to a mechanical dewatering unit 206 (e.g., a centrifuge, a belt press, or a filter press), dewatered, and the filtered carbonaceous materials (filter cake) is further processed for impurity removal.
[0077] Geotube dewatering uses geotubes for dewatering. Geotubes are large filter bags made of geotextile. The crushed ore or clay can be put into a geotube, and the water is allowed to drain, leaving solids in the geotube. After the geotube is filled with ore or clay, it is allowed to drain for some time. When the geotube collapses as water is drained, more ore or clay can be pumped into the geotube. After cycles of filling and draining, the geotube is filled (e.g., to capacity). The ore or clay can be dewatered further, if desired, by evaporative drying for several weeks. The dewatered ore can be further processed for impurity removal.
[0078] The system 200 further includes a detection and impurity removal system 208. In some examples, filtering the ore can include removing impurities and water to physically sort and detect the rare earth element. Crystallization can be used as a purification technique if impurities are present in very small quantities, or if the impurities have a very different solubility profile from the desired compound. Impurities can be easily removed if they are either more soluble or less soluble in the dewatered ore or clay than the REEs. In some examples, the carbonaceous materials can be beneficiated.
[0079] The beneficiation process can include heating the carbonaceous materials to one or more desired temperatures. The one or more desired temperature can be about 100 C. to about 500 C., such as in ranges of about 100 C. to about 290 C., 100 C. to about 150 C., about 125 C. to about 200 C., or about 150 C. to about 290 C. The temperature that the ore is heated to can be selected to selectively remove at least some of at least one of the impurities that are present in the ore. In other words, depending on the temperature to which the ore is heated, different impurities can be selectively removed from the carbonaceous materials to different extents. For example, the ore can be heated to a temperature of about 100 C. to about 150 C. to remove moisture from the carbonaceous materials and about 150 C. to about 290 C. to remove volatile metals from the raw carbonaceous materials. In some cases, the beneficiation process can include heating the ore to a first desired temperature. Heating the ore to the first desired temperature can remove one or more first impurities. In some embodiments, beneficiation can then include heating the ore to a second, higher desired temperature. Heating the ore to the second desired temperature can remove one or more second impurities.
[0080] The beneficiation process can include heating the ore to the desired temperature for a desired duration. The desired duration can be about 1 second to several days, such as in ranges of about 1 second to about 1 minute, about 30 seconds to about 30 minutes, about 1 minute to about 1 hour, about 30 minutes to about 3 hours, about 1 hours to about 5 hours, about 3 hours to about 10 hours, about 7 hours to about 18 hours, about 12 hours to about 1 day, or about 18 hours to about 3 days. Typically, increasing the duration that the ore is heated to the desired temperature can increase the amount of the one or more impurities that are removed from the ore. However, the ore can exhibit a maximum duration where heating the ore for periods of time longer than the maximum duration will have little or no effect on the amount of the one or more impurities that are removed from the ore. In some cases, the beneficiation process can include heating the ore to a first desired temperature for a first duration followed by heating the ore to a second, higher desired temperature for a second duration. The first and second durations can be the same or different.
[0081] In some examples, further processing of the ore after impurity removal and/or beneficiating the carbonaceous materials can include subjecting the beneficiated carbonaceous materials to a liquid extraction process, such as a pyrolysis process (e.g., a high temperature pyrolysis process or a mild temperature pyrolysis process). It is noted that other liquefaction processes can be used instead of or in conjunction with the pyrolysis process, such as using a direct liquefaction process or an indirect liquefaction process, membranes, an electric arc process, a super critical solvent extraction process, or an electromagnetic heating process. The liquid extraction process can convert the beneficiated carbonaceous materials into a pitch.
[0082] After the impurity removal system 208, the pitch can be rehydrated with a hydrating system 210. Carbonaceous pitch can be rehydrated to 6% to 8% moisture to avoid spontaneous combustion. After the impurity removal system 208, the ore can then be sorted with an ore sorting system 212. Physical sorting with sensor detection systems can be configured to separate ores including heavy REEs 214, ores including light REEs 216, and ores including other metals/elements 218 at this stage.
[0083] As described above, the heavy REEs 214 and the light REEs 216 can be separated in the sorting system 212 that includes a solvent extraction. Solvent extracting can include mixing various acids that have affinities for different rare earth elements and then allowing these mixtures to settle to gradually achieve higher concentrations of specific REE metals in each separation. In some examples, the solvent extraction can achieve purities higher than 99.9%. In some examples, ligands can be used to separate the REEs. In some examples, ion exchange and precipitation can be used for recovery of REEs from pregnant leach solutions obtained from acid leaching. However, other methods of extracting REEs can be utilized.
[0084] In one or all examples, the sorting system 212 can sort the REEs into light rare earth elements (LREEs), middle rare earth elements (MREEs), and heavy rare earth elements (HREEs). The LREEs can include elements from lanthanum (La, atomic number 57) to neodymium (Nd, atomic number 60), the MREEs can include elements from promethium (Pr, atomic number 61) to dysprosium (Dy, atomic number 66), and the HREEs can include elements from holmium (Ho, atomic number 67) to lutetium (Lu, atomic number 71). The LREEs can further include scandium (Sc, atomic number 21). The HREEs can further include yttrium (Y, atomic number 39). In one or all examples, the REEs can be sorted differently, or the boundaries between groups of the REEs can be defined differently. Once the REEs are sorted into LREEs, MREEs, and HREEs, the REEs can be further sorted into each specific REE. This can be accomplished through capture by ligands attached to carbon substrates (e.g., activated carbon fiber modules, fused monolithic carbon fiber, other forms of carbon fiber, or the like). The ligands can capture specific REEs, and these REEs can be subsequently released from the ligands by altering the pH of a solution including the ligands. The ligands can be designed to capture one or more specific REEs or other elements (e.g., germanium (Ge), gallium (Ga), or the like), and each element can be released from the ligands by adjusting the pH of a solution including the ligands to a specific value.
[0085] In some examples, extracting a rare earth element from a carbonaceous material deposit utilizing an electric swing adsorption system. Although an electric swing adsorption system is described, any of the examples of the present disclosure can use an electrothermal swing adsorption system or apparatus.
[0086]
[0087] The electric swing adsorption system 300 may include a plurality of electric swing adsorption apparatuses 310, 320, 330 that are arranged in series. The illustrated embodiment illustrates a first electric swing adsorption apparatus 310, a second electric swing adsorption apparatus 320, and a third electric swing adsorption apparatus 330. In other words, the pitch input flow stream 302 is filtered by the first electric swing adsorption apparatus 310, then is filtered again by the second electric swing adsorption apparatus 320, and then is again by the third electric swing adsorption apparatus 330. However, the present disclosure is not so limited, and the electric swing adsorption system 300 may include a greater or lesser number than three electric swing adsorption apparatuses to purify the pitch input flow stream 302.
[0088] In some embodiments, the electric swing adsorption apparatuses 310, 320, 330, of the electric swing adsorption system 300 may be arranged in parallel. In other words, the electric swing adsorption apparatuses 310, 320, 330 may filter the pitch input flow stream 302 simultaneously to increase the rate in which the REEs are removed from the pitch input flow stream 302.
[0089] Each of the electric swing adsorption apparatuses 310, 320, 330 may be functionalized for the capture of a specific REE. For example, the first electric swing adsorption apparatus 310 may be functionalized to remove gallium from the pitch input flow stream 302. The second electric swing adsorption apparatus 320 may be functionalized to remove germanium from the pitch input flow stream 302 after the first electric swing adsorption apparatus 310 has removed gallium. The third electric swing adsorption apparatus 330 may be functionalized to remove lanthanum from the pitch input flow stream 302 after the first electric swing adsorption apparatus 310 and the second electric swing adsorption apparatus 320 have removed gallium and germanium. The result is that the pitch output flow stream 304 is free of or to a large extent free of REEs. In some examples, the electric swing adsorption apparatuses 310, 320, 330 may be modified with a protein or other metal capture ligands and using the electro-swing to improve binding of the metal of interest. This could include specificity and selectivity of the target metal as well as increased quantity. Further, the captured metal can be expelled by reversing the swing to kick or expel the bound metal from the ligand or protein. The electric swing adsorption system 300 may include additional electric swing adsorption apparatuses to remove other specific REEs from the pitch input flow stream 302. For example, a fourth electric swing adsorption apparatus may be functionalized to remove an REE from the pitch input flow stream 302 after the first electric swing adsorption apparatus 310, the second electric swing adsorption apparatus 320, and/or the third electric swing adsorption apparatus 330 removed their intended REEs, respectively.
[0090] In some examples, the electric swing adsorption apparatuses 310, 320, 330 may include an active carbon monolith for adsorbing REEs explained in greater detail below. A first REE concentrated pitch stream 311 may transfer or output the pitch inlet stream 302 to a first temporary storage container for storing the concentrated REE pitch. A second concentrated pitch stream 321 may transfer or output the pitch inlet stream 302 to a second temporary storage container for storing the concentrated REE pitch. A third concentrated pitch stream 331 may transfer or output the pitch inlet stream 302 to a third temporary storage container for storing the concentrated REE pitch. In some examples, the first, second, and third temporary storage containers are different temporary storage containers that store a specific REEs. In some embodiments, the first, second, and third temporary storage containers are the same temporary storage container that stores all of the different REEs from the pitch.
[0091] In one or all examples, the electric swing adsorption apparatuses 310, 320, 330 may include active carbon monoliths that include ligands for capturing specific REEs. In other words, each of the electric swing adsorption apparatuses 310, 320, 330 can include activated carbon fiber modules that are coated with ligands that selectively target specific REEs and separate those REEs from the pitch. The pitch may be filtered through several of the electric swing adsorption apparatuses 310, 320, 330 to remove each selected REE from the pitch. The REEs captured by the ligands can then be selectively release by changing the pH of solutions that include the activated carbon fiber modules with the ligands that include captured REEs. As such, each REE in the pitch can be selectively captured.
[0092]
[0093] In the illustrated embodiment, the first chamber 412 includes an active carbon monolith for adsorbing REEs and the second chamber 413 includes a regenerating carbon monolith for desorbing captured REEs from the regenerating carbon monolith. The regenerating carbon monolith in the second chamber 413 had previously adsorbed REEs. In some embodiments, the carbon monolith in the second chamber 413 has not yet adsorbed REEs when it is first placed in the second chamber 413. The first chamber 412 and the second chamber 413 operate in a cyclical fashion to perform continuous adsorption and desorption of REEs.
[0094] The carbon monoliths of the first chamber 412 and the second chamber 413 each include carbonaceous material-based activated carbon fibers. The carbonaceous material-based activated carbon fibers are procured from a carbonaceous material feedstock. This can allow the carbonaceous material-based activated carbon fibers to be produced 50% to 75% more economically than existing fibers on the market produced from polyacrylonitrile (PAN), rayon, and petroleum pitch precursors. The carbon fiber can be produced by melt blowing isotropic pitch derived from sub-bituminous carbon ore by the direct coal liquefaction process (e.g., or a similar process for other carbonaceous materials).
[0095] The carbon monoliths and the carbonaceous material-based activated carbon fibers may be functionalized for the adsorption of a specific REE. Properties of the activated carbon fibers may be tailored so that selective adsorption is achieved. Properties of the activated carbon fibers may include pore diameter, pore size distribution, Brunauer-Emmett-Teller (BET) surface area, thermal conductivity, magnetism, bulk density, permeability, and electrical resistance. In some examples, functionalizing can include binding proteins or releasing in response to varying electrical charges. The carbon monolith of the first chamber 412 and the carbon monolith of the second chamber 413 may be similar so each carbon monolith targets the same specific REE, in some examples.
[0096] In one or all examples, ligands that can selectively bind REEs can be coupled to the carbon monoliths. The ligands can include lipids, glycolipids (e.g., ramnolipids, xylolipids, rhamnosides, galactolipids, lactolipids, or the like). In some examples, the ligands can include multi-dentate carboxylate complexing units or other chelating ligands. The ligands can include binding sites that can bind specific REEs. The REEs can be released by adjusting the pH of a solution including the carbon monoliths. The lipids can include functional linkers, which can be used to attach the ligands to the carbon monoliths. The ligands can be attached to the carbon monoliths in a single step or by a single chemical reaction. High purity ligands can be attached to the carbon monoliths to ensure that carbon monoliths in each reactor are highly selective to a single REE, or a small subset of REEs (e.g., two, three, or another small subset of REEs). In some examples, the ligands can include lipids (e.g., glycolipid ligands), which can be altered to bind other specific metals, such as, for example, gallium (Ga) and/or germanium (Ge).
[0097] For example, the bulk density of the carbon monoliths can be greater than about 0.05 g/cm.sup.3. In some examples, the bulk density of the carbon monolith can be within a range from about 0.05 g/cm.sup.3 to about 0.7 g/cm.sup.3. In some examples, the fiber areal weight range can include a bulk density less than about 0.7 g/cm.sup.3. In some examples, the bulk density can be less than 0.6 g/cm.sup.3, less than 0.5 g/cm.sup.3, or less than 0.1 g/cm.sup.3. In some examples the bulk density of the carbon monoliths can be in ranges between about 0.05 g/cm.sup.3 and about 0.2 g/cm.sup.3. Other ranges can include between about 0.2 g/cm.sup.3 and about 0.4 g/cm.sup.3, between about 0.4 g/cm.sup.3 and about 0.5 g/cm.sup.3, between about 0.5 g/cm.sup.3 and about 0.6 g/cm.sup.3, or between about 0.6 g/cm.sup.3 and about 0.7 g/cm.sup.3. In some examples, the bulk density can be adjusted by adjusting the temperature rate while forming the carbon fiber monolith but can also be adjusted by adjusting the airflow or oxygen concentration while forming the carbon fiber monolith.
[0098] In some examples, the permeability of the carbon monoliths can vary based primarily on the bulk density. In some examples, the permeability can also be affected by the fiber spacing and degree of melting at the nodes while forming the carbon fiber monoliths. In some examples, the permeability of the carbon monolith can be within a range from about 110.sup.10 m.sup.2 to about 8.510.sup.11 m.sup.2. In some examples, the permeability range can be less than about 9.810-11 m.sup.2. In some examples, the permeability can be less than about 9.510.sup.11 m.sup.2, less than about 9.010.sup.11 m.sup.2, or less than about 8.810.sup.11 m.sup.2. In some examples the permeability of the carbon monoliths can be in ranges between about 110.sup.10 m.sup.2 and about 9.810.sup.11 m.sup.2. Other ranges can include between about 9.810.sup.11 m.sup.2 and about 9.510.sup.11 m.sup.2, between about 9.510.sup.11 m.sup.2 and about 9.310.sup.11 m.sup.2, between about 9.310.sup.11 m.sup.2 and about 910.sup.11 m.sup.2, between about 910.sup.11 m.sup.2 and about 8.810.sup.11 m.sup.2, or between about 8.810.sup.11 m.sup.2 and about 8.510.sup.11 m.sup.2 The intrinsic permeability of a porous medium, such as a carbon monolith, measures its ability of letting a fluid pass through it under the influence of a pressure gradient. For practical applications, it is of high interest to predict the permeability of a given medium based on its porous structure.
[0099] Furthermore, properties of the activated carbon fibers can also be tailored to decrease the temperature and energy needed to desorb the REEs from the carbon monolith. As discussed in further detail below, an electric current can be applied to the carbon monolith to induce heat by electrical resistance of the carbon fibers in the carbon monoliths and increase their temperature to aid in the desorption process to remove the REEs from the regenerating carbon monolith. The electrical stimulation can cause the binding and unbinding of REEs from chelating ligand-formed complexes by electrostatic reaction of the functional unit to open and close the binding sites. This is enables specially designed ligands with lever-arm tails that cause reorientation of the molecular units to change the binding site size and binding energies for specific REE ions.
[0100] The first electric swing adsorption apparatus 410 includes a pitch feed 414. The pitch feed 414 may be the same as the pitch input flow stream 302. The pitch feed 414 includes REEs disposed in the pitch. The pitch feed 414 may include a variety of different REEs.
[0101] The pitch feed 414 follows a feed flow path 415 that includes a first pitch feed flow path 415A. The pitch feed flow path 415 is introduced or received into the first chamber 412 via the first pitch feed flow path 415A. The REEs are adsorbed by the active carbon monolith in the first chamber 412 thereby filtering the pitch feed 414. The first chamber 412 is coupled to the pitch output flow stream 404 so that the pitch feed 414 can exit the first chamber 412 via the first pitch output flow stream 404A. The pitch output flow stream 404, 404A includes a lower concentration of REEs as they were desorbed by the active carbon monolith in the first chamber 412. In some embodiments, the pitch output flow stream 404, 404A can be free of the specific REE that the carbon monolith in the first chamber 412 was functionalized for and may include additional REEs that will be removed by subsequent electric swing adsorption apparatuses (e.g., 320, 330) that are disposed later in series of the pitch input flow stream 302 of the electric swing adsorption system 300. As discussed above, the pitch output flow stream 404, 404A may then be introduced into the second electric swing adsorption apparatus 320 and then the third electric swing adsorption apparatus 330. After the pitch feed 414 is outputted from all of the electric swing adsorption apparatuses, the electric swing adsorption system 410 can filter the REEs at a significant rate.
[0102] The first electric swing adsorption apparatus 410 further includes a purge 416. The purge 416 is a reservoir of purge fluid that can be used in the desorption of the REEs from the carbon monolith in the second chamber 413. In some embodiments, a purge gas is used in the desorption process. The purge 416 follows a purge flow path 417 that includes a first purge flow path 417A. The purge 416 is introduced or received into the second chamber 413 via the first purge flow path 417A. The REEs are desorbed from the regenerating carbon monolith in the second chamber 413. The regeneration of the regenerating carbon monolith in the second chamber 413 is performed by applying an electric current to the regenerating carbon monolith to induce heat by electrical resistance of the carbon monolith and increase the temperature of the carbon monolith to between 100 C. and 150 C. The temperature to which the carbon monolith is heated can depend on the properties of the carbon monolith in the second chamber 413, the captured REEs being desorbed from the carbon monolith, and any chemical modifications of the carbon monolith. In some embodiments, the purge fluid is drained from the chamber before applying the electric current through the carbon monolith. The REEs are desorbed from the carbon monolith and into the purge 416. The REEs can be outputted out of the second chamber 413 through the concentrated pitch flow stream 411 via a first pitch flow stream 411A. In one or all examples, the purge 416 can include a solution at a specific pH, which can be used to release the REEs from the carbon monolith. For example, the purge 416 can include exposing the carbon monolith to an acidic solution, which can release the REEs captured by the carbon monolith.
[0103] The pitch flow stream 411 may be coupled to a temporary storage container 418 that collects and stores the REEs from the first electric swing adsorption apparatus 410, specifically the first chamber 412. As discussed above, the temporary storage container 418 may collect and store a specific REE that was adsorbed by the carbon monoliths in the first electric swing adsorption apparatus 410. In some embodiments, the temporary storage container 418 may include a flow path 419 that is in fluid communication with the pitch feed flow path 415 via a first flow path 419A and is in fluid communication with the purge flow path 417 via a second flow path 419B.
[0104] The first electric swing adsorption apparatus 410 operates in a continuous and cyclical manner. In other words, the pitch feed 414 (e.g. pitch input flow stream 302) is continuously introduced into the first chamber 412 to adsorb the REEs from the pitch feed 414 and the purge 416 is continuously introduced into the second chamber 413 to desorb the REEs from the carbon monolith in the second chamber 413. When the active carbon monolith in the first chamber 412 begins to reach a predetermined concentration/adsorption capacity (e.g., in other words, the carbon monolith cannot adsorb more REEs), the first electric swing adsorption apparatus 410 can be reversed. In other words, the carbon monolith in the first chamber 412 can be regenerated by desorbing the REEs from the carbon monolith using the purge 416 and the carbon monolith in the second chamber 413 can be activated by adsorbing REEs from the pitch feed 414. Accordingly, the first electric swing adsorption apparatus 410 continuously adsorbs and desorbs REEs using the carbon monoliths in the first chamber 412 and the second chamber 413.
[0105]
[0106] The first electric swing adsorption apparatus 410 in the second configuration includes the first chamber 412 and the second chamber 413. In the illustrated embodiment of the second configuration of the first electric swing adsorption apparatus 410, the first chamber 412 includes a regenerating carbon monolith for desorbing REEs and the second chamber 413 includes an active carbon monolith for adsorbing REEs. Previously, the regenerating carbon monolith of the first chamber 412 was the active carbon monolith of the first chamber 412 in the first configuration and the active carbon monolith of the second chamber 413 was the regenerating carbon monolith of the second chamber 413 in the first configuration. The first chamber 412 and the second chamber 413 operate in a cyclical fashion in this manner to perform continuous adsorption and desorption of REEs.
[0107] The first electric swing adsorption apparatus 410 includes the pitch feed 414. The pitch feed 414 may be the same as the pitch input flow stream 302. The pitch feed 414 includes REEs disposed in the carbonaceous pitch.
[0108] The pitch feed 414 follows a pitch feed flow path 415 that includes a second pitch feed flow path 415B. The pitch feed flow path 415 is introduced or received into the second chamber 413 via the second pitch feed flow path 415B. The REEs are adsorbed by the active carbon monolith in the second chamber 413 thereby filtering the pitch feed 414. The active carbon monolith in the second chamber 413 was the previous regenerating carbon monolith in the second chamber 413 in the first configuration. The second chamber 413 is coupled to the pitch output flow stream 404 so that the pitch feed 414 exits the second chamber 413. The pitch output flow stream 404 includes a lower concentration of REEs or can be free of REEs as they were desorbed by the active carbon monolith in the second chamber 413. In some embodiments, the pitch output flow stream 404, 404A is free of the specific REE that the carbon monolith in the first chamber 412 was functionalized for and may include additional REEs that will be removed by subsequent electric swing adsorption apparatuses (e.g., 320, 330) that are disposed later in series of the electric swing adsorption system 300. As discussed above, the pitch output flow stream 404 may then be introduced or received into the second electric swing adsorption apparatus 320 and then the third electric swing adsorption apparatus 330. As discussed above, after the pitch feed 414 can achieve significant reduction of REEs.
[0109] The regeneration of the regenerating carbon monolith in the first chamber 412 is performed by applying an electric current to the regenerating carbon monolith to induce heat by electrical resistance of the carbon monolith and increase the temperature of the carbon monolith to between 100 C. and 150 C. depending on the properties of the carbon monolith in the first chamber 412, the REEs being desorbed from the carbon monolith, and any chemical modifications of the carbon monolith. In some embodiments, the purge fluid is drained from the chamber before applying the electric current through the carbon monolith. The REEs are desorbed from the carbon monolith. The concentrated REEs in the purge 416 may be transferred out of the first chamber 412 through the concentrated pitch flow stream 411 via a second concentrated pitch flow stream 411B.
[0110]
[0111] In some examples, the method 500 includes an act 504 of feeding the pitch into a chamber of an electric swing adsorption apparatus. The pitch can include a relatively low concentration of REEs. In some examples, the pitch can include a concentration of REEs at about 400 ppm. The method 500 can further include an act 506 of adsorbing the rare earth element with a carbon monolith in the chamber. The carbon monolith includes a carbonaceous material-based activated carbon fiber. The carbon monolith can function as a filter and/or be functionalized to absorb REEs or a specific REE. In some examples, adsorbing the rare earth element with a carbon monolith in the chamber comprises moving the carbon monolith through the pitch. In some examples the carbon monolith moves from an adsorbing chamber to a desorbing chamber where individual REE ions are separated and concentrated.
[0112] In some examples, the method 500 can include an act 508 of outputting the pitch from the chamber of the electric swing adsorption apparatus. The pitch can exhibit a lower concentration of REEs. In some examples, the method 500 can further include an act 510 that includes applying an electrical current to the carbon monolith in the chamber to raise a temperature of the carbon monolith to desorb the rare earth element from the carbon monolith. In some examples, after desorption, the pitch can include a concentration of about 8000 ppm or greater.
[0113]
[0114] In some examples, the method 600 includes acid leaching the feedstock at a pH less than about 5, or less than about 3, capturing the rare earth element with a ligand, and releasing the rare earth element from the ligand. The rare earth element can be captured by a protein ligand, which can be attached to a substrate, such as a carbon-based substrate. The protein operates within a broad pH range (1.5 to 5). In some examples, the ligand can include a binding protein or a protein-based biosorbent. The protein can survive overnight hydrochloric acid incubation, which includes binding and releasing REEs after being rinsed with buffer. The protein has a wide operational temperature. In some examples, the ligand can include a lanmodulin (LanM) or another metal-binding protein. In other examples, the ligand can include a purified fusion protein CFP-RTX-EYFP or an RTX peptide. Extraction of REEs using the LanM REE binding protein system of bio-adsorption and desorption can be used to identify and separate REEs at high yields and purity.
[0115] Expression of the LanM onto the surface of a common bacterium yields a tool for the direct extraction of REEs from a leachate. A bacterium can display about 50,000 copies of the LanM protein, and each protein can include 3 highly specific REE binding sites. Thus, each bacterium has the capacity to bind about 150,000 REEs. In some examples, the ligand can include at least 6 binding sites. In some examples, the ligand can include 8 binding sites. In some examples, the LanM protein has a high selectivity as compared to common small-molecule chelators. The affinity of LanM for REEs, including Sc, is great enough so that at sub-PPB levels the REEs can be captured by the LanM protein. The LanM family of proteins have four binding sites1 that binds Ca+ and 3 that bind the REEs and Sc.
[0116] In some examples, prior to acid leaching, the feedstock can be beneficiated (not shown). Beneficiating the feedstock comprises heating the feedstock to a first temperature for a first duration and then heating the feedstock to a second, higher temperature for a second duration. In some examples, the feedstock can be crushed. In other words, the feedstock can include a carbonaceous material deposit that is crushed and/or filtered to form a carbonaceous material particulate. The carbonaceous material particulate can include the rare earth element and metal impurities.
[0117] In some examples, the method 600 includes acid leaching the feedstock. Leaching is the process in which the ore is concentrated by chemical reaction with a suitable reagent which dissolves the ore but not the impurities. For example, the feedstock can include a pregnant leach solution with the pH adjusted to about pH 5. The potential exists that the interfering metals (e.g., Fe, Al, Ca, Mg, Na, K, Ti, P, Mn, Cr, V, and/or Zn) may not need to be remediated through precipitation. Thus, the leachate can be directly input into the LanM separation and speciation circuit. In some examples, the acid leaching is at a pH less than about 5.0. In some examples, the pH is less than about 3.0.
[0118] In some examples, the method 600 is configured to extract at least about 80% of the rare earth element from the feedstock. In some examples, the separation of the rare earth element from the protein-based bio-sorbent or ligand can include different backbones or scaffolds from which to develop novel environmentally friendly binding ligands. For example, the RTX protein (modified and unmodified) can be used in the first steps of REE extraction. In a column format, once the REEs are bound to RTX, the column can be washed, and then the REEs released. This solution can then be applied to columns with the LanM proteins for speciation. The source of the proteins (LanM or RTX) could be bacteria, yeasts, or cell free extracts, or eukaryotic cell lines.
[0119] Referring to
[0120] In some examples, the method 700 can also include an act 704 of ore processing. The ore processing can include forming a first pregnant leachate including the carbonaceous material particulate and a ligand. In some examples, act 704 can include filtering or settling the pregnant leachate to remove particulate from the solution. In some examples, the ligand can include a lipid ligand (e.g., a glycolipid ligand). In some examples, the ligand can include a rhamnolipid and xylulose base molecules. These base molecules can be modified with functional groups-either carboxylic acid or phosphoric acid.
[0121] The method 700 can further include an act 706 that includes extracting the metal impurities via an ion exchange or floatation to form a reduced leachate. The kinetics of a column-based format should be significantly better than a floatation system. Kinetics should be fast enough to load the columns to 70 or 80% of capacity-based on PPM. For example, the column can be loaded, then pause for a few minutes, then drain the unbound solution, wash with 1 volume, then release with 1 bed volume. The washed column can then be loaded with a second pregnant leachate solution. In some examples, act 706 further includes forming a second pregnant leachate including the reduced leachate and the ligand.
[0122] In some examples, the method 700 can further include an act 708 of extracting the rare earth element from the reduced leachate via an acid leaching. The method 700 further includes an act 710 of capturing the rare earth element in the binding site of the ligand via solvent extraction. In some examples, the method further includes an act 712 of desorbing the rare earth element from the ligand to separate the rare earth element from the ligand. In some examples, the method 700 can also include separating and recycling the ligand after extracting the metal impurities and after desorbing the rare earth element from the ligand. In the example, desorbing the rare earth element from the ligand comprises controlling the pH to release the rare earth element based on an atomic number of the rare earth element. In some examples, the number of times the column can be cycled is in range of 1,000s. This can be an automated system using a simple synthetic PLS to capture and release the REEs.
[0123] Referring now to
[0124] In some examples, the system can further include a second solution configured to separate the reduced solution and capture at least one rare earth element from the reduced solution. The system further includes a third solution configured to release the captured at least one rare earth element. The carbonaceous material particulate includes at least one rare earth element and metal impurity therein. In some examples, each of the first solution and the second solution can include a binding ligand expressed on a column configured to capture the rare earth element. The ligand can include a rare earth element binding protein. In some examples, the first separator and the second separator operate in a cyclical fashion to recycle the ligand. In at least one example, the ligand is functionalized to capture a predefined category of rare earth element. The rare earth element can be a HREE, a MREE, or a LREE.
[0125] For example, as shown in
[0126] In some examples, the extraction can include a two-cycle circuit: Cycle 1the PLS is loaded onto the LanM column, Sc (99% pure) is released from the protein using a Malonate desorption. Followed by a decreasing pH desorption of yttrium and the lanthanides from LanM released into groups of HREE at a pH 2.3, LREE at a pH 2.1, and MREE at a pH 1.9. Cycle 2the effluents from Cycle 1 (HREE, LREE, & MREE) are pH adjusted to greater than pH 3, and reloaded on to the LanM column. Then further separated using a Citrate-pH desorption. This results in a HREE group that is 88-100% pure, High Purity Y at 92% pure, MREE group at about or greater than 80% and LREE at about or greater than 98%. A complete system can recover, at high purity and yield: Sc, Ga, Ge, Nd, Dy, Pr, and Tb and have a high yield and purity solution of mixed REEs as an additional by-product. The system can recover Nd and Dy at high purity and yield with a pH-citrate elution followed by a malonate elution.
[0127] Referring to
[0128] In one or all examples, ligands, lipids (e.g., glycolipids), proteins (e.g., LanM), and other molecules that include binding sites for capturing REEs can be formed in bioreactors. The bioreactors can include hollow fiber bioreactors.
[0129] In one or all examples, a multi-stage system can be used for purifying various products from carbonaceous materials. The system can include a first stage in which the carbonaceous materials are liquified. The system can include a second stage in which REEs are removed from the liquified carbonaceous materials. The system can include a third stage in which gallium and germanium are removed from an effluent stream of the liquified carbonaceous materials. The system can include a fourth stage in which each specific REE is separated from the other REEs. The system can include a fifth intermediate stage, which can be included between the second stage and the fourth stage. In the fifth stage, the REEs can be separated into LREEs, MREEs, and HREEs. Additional stages can be included for isolating other elements, such as aluminum, titanium, and the like. Ligands, such as lipids (e.g., glycolipids), can be attached to activated carbon fiber substrates and used to capture any elements in any of the above-described stages. The captured elements can be released through adjusting the pH of solutions that include carbon fiber substrates with ligands that have captured the target elements. The ligands can be attached to carbon fiber substrates through single step chemical reactions (e.g., by attaching carboxylic acids by Diels Adler reaction) or through multiple step chemical reactions.
[0130] There are issues of hazardous chemicals, high energy consumption, and inefficient extraction and purification of REEs in existing carbonaceous material liquefaction processes. Therefore, in order to solve the above problems, the present disclosure provides a method for REE metal extraction and purity during direct coal liquefaction (e.g., or other direct carbonaceous material liquefaction) by adding ionic liquids and separating with functionalized activated carbon fiber (ACF) filters and chromatography columns. In some examples, REE extraction can be performed in a column as described in Yimu Hu et al., Size-Selective Separation of Rare Earth Elements Using Functionalized Mesoporous Silica Materials, ACS Publications (May 22, 2019), https://pubs.acs.org/doi/10.1021/acsami.9b04183, which is incorporated herein by reference in its entirety.
[0131] Compared with conventional approaches, the present disclosure provides a method for REE metal extraction and purity during direct coal liquefaction by adding ionic liquids and separating with functionalized activated carbon fiber (ACF) filters and chromatography columns, and has the following beneficial effects: 1. The use of ionic liquids as an alternative to highly corrosive solutions, such as HF and concentrated H2O2, significantly reduces the environmental and safety risks associated with the extraction process, making it a more sustainable and worker-friendly method. 2. The combination of functionalized ACF filters and chromatography columns allows for efficient separation and purification of REEs from the carbonaceous tar pitch and other byproducts of liquefaction, resulting in higher yields and better quality of the extracted materials. 3. The functionalized ACF filters can be optimized to release specific species by applying an electric charge, enabling better control and selectivity in the extraction process and potentially allowing for the recovery of multiple components simultaneously. 4. The use of a moving bed sorbent system with a multiple component train design enables the purification and separation of multiple components concurrently, addressing drawbacks of existing processes that lack the ability to effectively capture and remove multiple contaminants simultaneously. 5. The method utilizes carbon-based materials for the extraction and purification process, making it a carbon-centric approach that aligns with the growing interest in exploring alternative uses for carbonaceous materials and carbonaceous material-derived products.
[0132] Another example provides a method for REE metal extraction and purity during direct coal liquefaction, which includes: Step 1, preparing the carbonaceous material feed and ionic liquid solution; Step 2, extracting REEs from the carbonaceous material feed using the ionic liquid solution; Step 3, separating the extracted REEs from the carbonaceous tar pitch; Step 4, purifying the separated REE-containing fraction; Step 5, isolating pure REE compounds.
[0133] Step 1 includes: Step 101, selecting a suitable ionic liquid for REE extraction, such as a basic ionic liquid containing nitrogen, oxygen, and fluorine atoms; Step 102, preparing a carbonaceous material feed solution by mixing carbonaceous materials, carbonaceous material by-products, ore, or electronic waste with the ionic liquid in a ratio of 1:2 to 1:10 (w/v); Step 103, subjecting the carbonaceous material feed solution to microwave irradiation for 2-5 minutes to enhance the extraction efficiency.
[0134] Step 2 includes: Step 201, maintaining the temperature of the solution at 80-100 C. using a stirring hotplate or a commercial microwave oven; Step 202, agitating the solution continuously for 30-60 minutes to ensure complete extraction of REEs; Step 203, filtering the solution to remove undissolved particles.
[0135] Step 3 includes: Step 301, passing the filtered solution through a set of functionalized activated carbon fiber (ACF) filters arranged in a moving bed sorbent system; Step 302, applying an electric charge to the ACF filters to optimize the binding and release of specific ions; Step 303, collecting the fraction containing REEs and other valuable metals.
[0136] Step 4 includes: Step 401, passing the collected fraction through a chromatography column filled with a cation exchange resin; Step 402, eluting the adsorbed REEs from the column using a mixture of water and ethanol (70:30 v/v); Step 403, concentrating the eluate under vacuum and heating to remove the solvent.
[0137] Step 5 includes: Step 501, precipitating REE salts by adding a stoichiometric excess of ammonium bicarbonate; Step 502, filtering the precipitate and washing it with water and ethanol; Step 503, drying the purified REE salts at 80-100 C. for 4-6 hours; Step 504, calcining the dried salts at 400-600 C. for 2-4 hours to obtain pure REE oxides.
[0138] The method may further include: Step 6, repeating Steps 2-5 to maximize the extraction of REEs from the carbonaceous material feed, using the same ionic liquid or a different ionic liquid each time; Step 7, analyzing the residual carbonaceous tar pitch for potential co-products and recycling it if valuable.
[0139]
[0140] The system 900 can include a source 902. The source 902 can be a source for raw materials for the system 900. The source 902 can include a coal mine, a clay mine, a source of coal or clay ores, coal ash (e.g., resulting from combusting coal), refuse rock from power plants, acid mine drainage treatment sludge, young lignite coal, peat, wastewater, other water sources, other carbonaceous material sources or the like. The source 902 can include various raw materials that include REEs, as discussed throughout the present disclosure. The source 902 can be a low ore grade, such as an ore grade having about 450 ppm of rare earth oxides (REOs). The source 902 can have greater or lower concentrations of REEs and REOs.
[0141] Raw materials from the source 902 can be fed to a feed processor 904. The feed processor 904 can prepare the raw materials from the source 902 for further processing by the system 900. The feed processor 904 can include a crusher, which can crush the raw materials from the source 902 into raw material/ore particles with desired sizes. The desired sizes can include diameters between about 1 m and 1 cm and can include any of the particle diameters described herein. The feed processor 904 can further include further include equipment that washes, sorts, and otherwise processes the raw materials from the source 902.
[0142] Materials from the feed processor 904 can then be fed to a heater 906. The heater 906 can roast ore or other materials from the feed processor 904 and can be considered a pre-treatment step of the system 900. The heater 906 can perform thermal roasting and/or chemical roasting of materials from the feed processor 904. The heater 906 can increase the effectiveness of subsequent equipment and steps performed on the materials output from the heater 906. In some examples, inlet water 908 can be added to the heater 906, to act as a catalyst for oxidation, alter pore structures in the material output from the heater 906, aid in the release of volatile chemicals or elements from the materials in the heater 906, or the like.
[0143] The materials from the heater 906 can then be fed to a separator 910. An inlet solution 912 can also be fed to the separator 910. The inlet solution 912 can include water and/or a leaching agent. The separator 910 can perform alkali leaching and filtration of the materials from the heater 906. The separator 910 can outlet a leach solution 914 (e.g., a pregnant leach solution (PLS) to a separator 916 and material can be outlet from the separator 910 to a separator 936.
[0144] The separator 916 can include one or more aluminum and gallium crystallization and filtration precipitation reactors. The solution 914 and an inlet solution 918 can be fed to the separator 916. The inlet solution 918 can include a pH modifier, such as lime. By reacting the solution 914 with the inlet solution 918, a precipitate including gallium and aluminum can be formed. The precipitate from the separator 916 can be provided to a separator 922. The solution in the separator 916 can be recycled to the separator 910 as a reagent recycle 920.
[0145] The precipitate from the separator 916 and an inlet solution 924 can be provided to a separator 922. The separator 922 can be a hydroxide solubilization and gallium and germanium recovery separator. The inlet solution 924 can include a re-leach reagent, such as sulfuric acid. The separator 922 can perform various precipitation reactions to separate the precipitate from the separator 916 into a product 926, a product 928, and an inlet for a separator 930. The product 926 can include metal hydroxides (e.g., other than aluminum hydroxide). The product 928 can include gallium and germanium (e.g., or oxides of gallium and germanium).
[0146] An outlet of the separator 922 including aluminum (e.g., aluminum hydroxide) and an inlet solution 932 can be provided to a separator 930. The inlet solution 932 can include a caustic solution or substance, such as sodium hydroxide. The separator 930 can treat the aluminum product from the separator 922 to form a product 934. The product 934 can include alumina hydroxide.
[0147] An outlet of the separator 910 can be provided to a separator 936. An inlet solution 938 can also be provided to the separator 936. The inlet solution 938 can include a leaching agent (e.g., sulfuric acid) and/or water. The separator 936 can perform secondary acid leaching. The separator 936 can remove impurities from the outlet of the separator 910. For example, the separator 936 can produce a product 940, which can include filter cake.
[0148] An outlet of the separator 936 can be provided to a separator 942. An inlet solution 944 can also be provided to the separator 942. The inlet solution 944 can include a pH modifier (e.g., a caustic solution) and/or water. The separator 942 can remove impurities from the outlet of the separator 936. For example, the separator 942 can remove iron impurities and any impurities that might be detrimental to ion exchange from the outlet of the separator 936. The separator 942 can outlet a stream of impurities 946.
[0149] An outlet of the separator 942 can be provided to a separator 948. An inlet solution 950 can also be provided to the separator 948. The inlet solution 950 can include a precipitation agent (e.g., soda ash and/or hydrochloric acid) and/or water. The separator 948 can include a precipitation reactor and can be used to separate rare earth elements from the outlet of the separator 942. The separator 948 can include any rare earth element extractors discussed in the present disclosure. For example, the separator 948 can include activated carbon fiber substrates that include ligands or the like, which can capture one or more specific rare earth elements. The separator 948 can be used to produce a product 952 and a product 954. The product 952 can include REEs or REOs. The 954 can include scandium. The product 954 can subsequently be separated into groups of REEs (e.g., LREEs, MREEs, and/or HREEs), individual REEs, or the like, as described in the present disclosure.
[0150] The method of REE metal extraction can be accomplished by several embodiments or examples. For example, a first embodiment can provide a method for REE metal extraction and purity during direct coal liquefaction or another direct carbonaceous material liquefaction. The method is implemented as follows: Step 1: Preparing the carbonaceous material feed and ionic liquid solution. This can include: Step 101: An ionic liquid, [9][10], is selected for REE extraction due to its high solubility for REE salts and relatively low melting point. Step 102: A carbonaceous material feed solution is prepared by mixing 100 g of Pennsylvania anthracite coal (particle size: 200-400 m) with 200 mL of [9][10] in a ratio of 1:2 (w/v) in a 500 mL Erlenmeyer flask. Step 103: The carbonaceous material feed solution is subjected to microwave irradiation for 3 minutes at 700 W using a household microwave oven to enhance the extraction efficiency.
[0151] Step 2: Extracting REEs from the carbonaceous material feed using the ionic liquid solution. This can include: Step 201: The temperature of the solution is maintained at 90 C. using a stirring hotplate set at 900 rpm. Step 202: The solution is agitated continuously for 45 minutes to ensure complete extraction of REEs. Step 203: The solution is filtered using a Whatman No. 40 filter paper to remove undissolved particles.
[0152] Step 3: Separating the extracted REEs from the carbonaceous tar pitch. This can include: Step 301: The filtered solution is passed through a moving bed sorbent system including three glass columns (inner diameter: 10 mm, length: 300 mm) filled with 10 g of functionalized activated carbon fiber (ACF) filters. Step 302: An electric charge of +4 kV is applied to the ACF filters using a high-voltage power supply to optimize the binding and release of specific ions. Step 303: The fraction containing REEs, and other valuable metals is collected in a receiver flask.
[0153] Step 4: Purifying the separated REE-containing fraction. This can include: Step 401: The collected fraction (50 mL) is passed through a chromatography column (inner diameter: 20 mm, length: 200 mm) filled with 20 mL of Dowex 50W-X8 cation exchange resin. Step 402: The adsorbed REEs are eluted from the column using a mixture of 30 mL of ethanol and 70 mL of water. Step 403: The eluate is concentrated under vacuum using a rotary evaporator at 60 C. to remove the solvent.
[0154] Step 5: Isolating pure REE compounds. This can include: Step 501: REE salts are precipitated by adding 10 mL of 28% ammonium bicarbonate solution (excess). Step 502: The precipitate is filtered using a Buchner funnel and washed with 100 ml of water followed by 50 mL of ethanol. Step 503: The purified REE salts are dried in a vacuum oven at 90 C. for 5 hours. Step 504: The dried salts are calcined in a muffle furnace at 500 C. for 3 hours to obtain pure REE oxides.
[0155] A second embodiment can provide a method for REE metal extraction and purity during direct coal liquefaction or another direct carbonaceous material liquefaction. The method is implemented as follows: Step 1: Preparing the carbonaceous material feed and ionic liquid solution. This can include: Step 101: A basic ionic liquid, [11][COO], is selected for its high stability and low melting point. Step 102: A carbonaceous material feed solution is prepared by mixing 150 g of Illinois bituminous coal (particle size: 150-300 m) with 300 mL of [11][COO-] in a ratio of 1:2 (w/v) in a 1 L beaker. Step 103: The carbonaceous material feed solution is subjected to microwave irradiation for 4 minutes at 800 W using a commercial microwave oven to enhance the extraction efficiency.
[0156] Step 2: Extracting REEs from the carbonaceous material feed using the ionic liquid solution. This can include: Step 201: The temperature of the solution is maintained at 95 C. using a magnetic stirrer set at 1000 rpm. Step 202: The solution is agitated continuously for 55 minutes to ensure complete extraction of REEs. Step 203: The solution is filtered using a cellulose acetate membrane filter with a pore size of 0.2 m to remove undissolved particles.
[0157] Step 3: Separating the extracted REEs from the carbonaceous tar pitch. This can include: Step 301: The filtered solution is passed through a moving bed sorbent system including four glass columns (inner diameter: 15 mm, length: 400 mm) filled with 15 g of functionalized activated carbon fiber (ACF) filters. Step 302: An electric charge of +5 kV is applied to the ACF filters using a programmable high-voltage power supply to optimize the binding and release of specific ions. Step 303: The fraction containing REEs, and other valuable metals is collected in a collection system.
[0158] Step 4: Purifying the separated REE-containing fraction. This can include: Step 401: The collected fraction (75 mL) is passed through a chromatography column (inner diameter: 25 mm, length: 250 mm) filled with 25 mL of Amberlite IRC-50 cation exchange resin. Step 402: The adsorbed REEs are eluted from the column using a mixture of 35 mL of ethanol and 65 mL of water.
[0159] Step 5: Isolating pure REE compounds. This can include: Step 501: REE salts are precipitated by adding 15 mL of 25% ammonium carbonate solution (excess). Step 502: The precipitate is filtered using a vacuum filtration system and washed with 150 ml of water followed by 75 mL of ethanol. Step 503: The purified REE salts are dried in a convection oven at 95 C. for 6 hours. Step 504: The dried salts are calcined in a tube furnace at 550 C. for 3.5 hours to obtain pure REE oxides.
[0160] As used herein, the term about or substantially refers to an allowable variance of the term modified by about or substantially by +10% or +5%. Further, the terms less than, or less, greater than, more than, or or more include, as an endpoint, the value that is modified by the terms less than, or less, greater than, more than, or or more.
[0161] The foregoing description, for purposes of explanation, used specific nomenclature to provide a thorough understanding of the described embodiments. However, it will be apparent to one skilled in the art that the specific details are not required in order to practice the described embodiments. Thus, the foregoing descriptions of the specific embodiments described herein are presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the embodiments to the precise forms disclosed. It will be apparent to one of ordinary skill in the art that many modifications and variations are possible in view of the above teachings.
[0162] Various embodiments have been described herein with reference to certain specific examples. However, they will be recognized by those skilled in the art that many variations are possible without departing from the scope and spirit of the embodiments disclosed herein, in that those embodiments set forth in the claims below are intended to cover all variations and modifications of the disclosure without departing from the spirit of the embodiments.