Method of preparing high-performance green building material based on combustion flue gas carbon dioxide mineralization

Abstract

A method of preparing a high-performance green building material based on combustion flue gas carbon dioxide mineralization, including: calculating a raw material ratio; taking each industrial solid waste material to obtain a solid powder; pouring the solid powder, dihydrate gypsum and gel material into a granulator, mixing uniformly, and then taking a part of the mixture, and then stirring the remaining mixture with deionized water sprayed until spherical kernels are formed, uniformly adding the previously-taken part of mixture to prepare an aggregate; performing hydration reaction on the aggregate; drying the hydrated aggregate to prepare spherical ceramic granules; placing the ceramic granules into a reaction kettle and introducing a combustion flue gas containing CO.sub.2 for mineralization reaction, and taking out reacted ceramic granules and putting into drying oven for drying to prepare a cold-bonded lightweight aggregate; supplementing water to the lightweight aggregate to perform hydration reaction and obtain a finished product.

Claims

1. A method of preparing a high-performance green building material based on combustion flue gas carbon dioxide mineralization, comprising: calculating a raw material ratio: screening industrial solid waste materials and calculating a ratio of the industrial solid waste materials, comprising: based on an association relationship diagram of CaO, SiO.sub.2 and Al.sub.2O.sub.3 components contained in the industrial solid waste materials with CO.sub.2 reactivity, preliminarily selecting a ratio interval of the components with CO.sub.2 high reactivity, setting a plurality of component ratios in the ratio interval, calculating a corresponding CO.sub.2 upper limit required for theoretical mineralization, and selecting an optimal component ratio; pre-treatment: based on the optimal component ratio, taking each industrial solid waste material, grinding, screening, and drying to obtain a solid waste powder, wherein the industrial solid waste materials comprise at least two of a fly ash, a coal gangue, a steel slag, and an iron tailing; granulation: pouring the solid waste powder, dihydrate gypsum, and a gel material into a granulator, mixing uniformly at a first rotation speed, and then taking a part of a mixture, and then at a second rotation speed, stirring a remaining mixture with a proper amount of deionized water sprayed until spherical kernels are formed, and then uniformly adding the part of the mixture and finally screening out balls with a diameter of 5 to 16 mm as an aggregate, wherein the first rotation speed is lower than the second rotation speed; a ratio of the solid waste powder to the gel material is (4.5 to 30): 6; the gel material is a cement; pre-curing: placing the aggregate in a drying oven with a constant temperature and humidity to perform a first hydration reaction; drying: placing the hydrated aggregate into a baking oven to dry and remove water in pores and then taking samples from the baking oven and cooling down to room temperature to prepare moulded ceramic granules and then storing in a sealing way; carbon dioxide mineralization curing: placing the moulded ceramic granules into a reaction kettle, introducing a combustion flue gas containing CO.sub.2 for a mineralization reaction under a given condition of temperature, humidity, and pressure, taking out reacted ceramic granules and putting into the drying oven for drying to prepare a cold-bonded lightweight aggregate; assisted hardening curing: supplementing water to the cold-bonded lightweight aggregate to perform a second hydration reaction and obtain a finished product, wherein the grinding, screening, and drying comprise: grinding and screening to below 60 meshes, and putting into a 65 C. baking oven to dry for 6 h and then taking out and cooling down naturally and wherein in a granulation process, the first rotation speed is 15 rpm to 20 rpm and the second rotation speed is 80 rpm to 90 rpm.

2. The method of preparing the high-performance green building material based on the combustion flue gas carbon dioxide mineralization of claim 1, wherein in a pre-curing process, curing is performed for 24 h with a curing temperature of 23 C. and a curing humidity of 60% RH.

3. The method of preparing the high-performance green building material based on the combustion flue gas carbon dioxide mineralization of claim 1, wherein in the drying process, the hydrated and cured aggregate is put into a 120 C. baking oven to dry 2 h to remove the water in the pores.

4. The method of preparing the high-performance green building material based on the combustion flue gas carbon dioxide mineralization of claim 1, wherein in a carbon dioxide mineralization curing process, a curing condition is: temperature 23 C., humidity 75% RH, pressure 1 to 1.5 MPa, and a carbon dioxide volume fraction 15% to 30%.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIGURE is a schematic diagram illustrating a flowchart of a method of the present disclosure.

DETAILED DESCRIPTION OF THE EMBODIMENTS

(2) The specific embodiments of the present disclosure will be described below.

(3) With reference to the FIGURE, there is provided a method of preparing a high-performance green building material based on combustion flue gas carbon dioxide mineralization, which includes:

(4) In the method of the present disclosure, a flow of pre-curing-mineralization curing-assisted hardening curing is employed to avoid the damage of the flue gas curing to the aggregate structure, realizing regulation and improvement for the internal structure of the aggregate building material and effectively increasing its CO.sub.2 absorption and mineralization capability and further increasing the comprehensive quality of the finished building materials. Furthermore, with waste incineration flue gas, optimization and regulation are performed for CO.sub.2 curing, realizing the purpose of controlling wastes with wastes.

(5) The method of the present disclosure will be further described below by using specific embodiments.

(6) The illustrated embodiments are used only to interpret the present disclosure rather than to limit the scope of the present disclosure. Those embodiments without marked conditions are to be carried out under normal conditions. All reagents or instruments without marked manufacturers are conventional products obtained commercially.

(7) In the following embodiments, the used solid waste materials include coal gangue and fly ash, the gel material is cement, and the combustion flue gas containing CO.sub.2 is obtained by simulation in the lab. The basic composition is indicated in Table 1, and the leaching concentrations of heavy metals in three raw materials detected by using the acetic acid solution buffer method are indicated in Table 2.

(8) TABLE-US-00001 TABLE 1 main chemical composition in raw materials (wt %) Composition SiO.sub.2 Al.sub.2O.sub.3 CaO SO.sub.3 Fe.sub.2O.sub.3 Na.sub.2O TiO.sub.2 MgO other Fly ash 26.53 23.79 1.28 16.08 2.73 2.26 1.30 0.182 25.848 Coal gangue 52.82 23.73 1.6 0.322 3.71 0.450 0.807 0.728 15.833 Cement 22.54 7.83 50.81 4.67 3.48 0.393 0.454 3.60 6.223

(9) TABLE-US-00002 TABLE 2 contents of some heavy metals in raw materials (mg/kg) Coal environmental Fly ash gangue standard value * As 318.6 46.3 600 (mg/kg) Cr 117 141.33 6.7 (mg/kg) Ni 57.33 111.33 900 (mg/kg) Pb 3547.67 143 800 (mg/kg) Cu 1097.67 63.67 1800 (mg/kg) Cd 11.25 65 (mg/kg)

Embodiment 1

(10) There is provided a method of preparing a high-performance green building material based on combustion flue gas carbon dioxide mineralization, which includes: calculating a raw material ratio: screening industrial solid waste materials, calculating a ratio of the materials, where the materials include coal gangue, that is, the ratio of the coal gangue to other materials is 1:0; pre-treatment: grinding the coal gangue and screening to below 60 meshes and then putting into a 65 C. baking oven for drying for 6 h and then taking out and cooling down naturally, so as to obtain a solid waste powder; granulation: pouring the solid waste powder, dihydrate gypsum and gel material into a granulator, mixing uniformly at the rotation speed of 15 rpm to 20 rpm, taking out a part of the mixture, and then at the rotation speed of 80 rpm to 90 rpm, stirring the remaining mixture with a proper amount of deionized water sprayed until spherical kernels are formed, then uniformly adding the previously-taken part of mixture and finally screening out balls with a diameter of 5 to 16 mm as aggregate; pre-curing: placing the aggregate in a drying oven with constant temperature and humidity to perform hydration reaction for 24 h at a curing temperature of 23 C. and a curing humidity of 60% RH; drying: placing the hydrated aggregate into a 120 C. baking oven to dry for 2 h and remove water in pores and then taking the samples from the baking oven and cooling down to room temperature to prepare moulded ceramic granules and then storing in sealing way; carbon dioxide mineralization curing: placing the ceramic granules into a reaction kettle, introducing a combustion flue gas containing CO.sub.2 for mineralization reaction for 72 h under the condition of temperature 23 C., humidity 75% RH, pressure 1 to 1.5 MPa and carbon dioxide volume fraction 15% to 30%, taking out the reacted ceramic granules and putting into the drying oven for drying to prepare a cold-bonded lightweight aggregate; assisted hardening curing: supplementing water to the lightweight aggregate to perform hydration reaction and obtain a finished product.

(11) Based on the above steps, the ratio of the coal gangue to the cement is adjusted to perform performance test on the finally-obtained finished product, with the performance test results shown in Table 3. The heavy metal test results are shown in Table 4.

(12) TABLE-US-00003 TABLE 3 performance test results of lightweight aggregates with different components in the coal gangue/cement system coal Apparent 1 h water gangue/ Bulk Density density/ absorption cement density /kg .Math. m.sup.3 level kg .Math. m.sup.3 rate/% 5:2 1055.7 1100 1650 11.88 2:1 1065.3 1100 1788 12.42 3:2 1037.3 1100 1692 10 4:3 1103.3 1100 2100 7.95 3:4 1103.3 1200 2200 8.29

(13) TABLE-US-00004 TABLE 4 heavy metal results before and after curing in different components in the coal gangue/cement system 5:2 3:2 Environmental Uncured Cured Uncured Cured limit * As 0.1 Cd 0.3 Cr 0.03 Pb 0.399 0.412 0.2 Cu 0.002 1.0 Ni 0.047 0.007 0.004 0.2 Mn 1.0 Zn 0.416 0.034 0.473 1.0

Embodiment 2

(14) There is provided a method of preparing a high-performance green building material based on combustion flue gas carbon dioxide mineralization, which includes: calculating a raw material ratio: screening the industrial solid waste materials as coal gangue and fly ash, and calculating a ratio of the two materials: based on an association relationship diagram of CaO, SiO.sub.2 and Al.sub.2O.sub.3 contained in the industrial solid waste materials with CO.sub.2 reactivity, preliminarily selecting a ratio interval of the components with CO.sub.2 high reactivity, setting multiple component ratios in this interval, calculating corresponding CO.sub.2 upper limit required for theoretical mineralization, and selecting an optimal component ratio; based on the optimal component ratio and the contents of the components in the materials, determining a ratio of the two materials; pre-treatment: based on the ratio, taking coal gangue and fly ash, grinding and screening to below 60 meshes, and putting into 65 C. baking oven to dry for 6 h and then taking out and cooling down naturally to obtain a solid waste powder; granulation: pouring the solid waste powder, dihydrate gypsum and gel material into a granulator, mixing uniformly at the rotation speed of 15 rpm to 20 rpm, and then taking a part of the mixture, and then at the rotation speed of 80 rpm to 90 rpm, stirring the remaining mixture with a proper amount of deionized water sprayed until spherical kernels are formed, and then uniformly adding the previously-taken part of mixture and finally screening out balls with a diameter of 5 to 16 mm as aggregate; pre-curing: placing the aggregate in a drying oven with constant temperature and humidity to perform hydration reaction for 24 h under the condition of a curing temperature 23 C. and a curing humidity 60% RH; drying: placing the hydrated aggregate into a 120 C. baking oven to dry for 2 h and remove water in pores and then taking the samples from the baking oven and cooling down to room temperature to prepare moulded ceramic granules and then storing in a sealing way; carbon dioxide mineralization curing: placing the ceramic granules into a reaction kettle, introducing a combustion flue gas containing CO.sub.2 for mineralization reaction for 72 h under the condition of temperature 23 C., humidity 75% RH, pressure 1 to 1.5 MPa and carbon dioxide volume fraction 15% to 30%, taking out the reacted ceramic granules and putting into the drying oven for drying to prepare a cold-bonded lightweight aggregate; assisted hardening curing: supplementing water to the lightweight aggregate to perform hydration reaction and obtain a finished product.

(15) Based on the above steps, the ratio of the fly ash to the coal gangue is adjusted to perform performance test on the finally-obtained finished product. The test results of the bulk densities of the finished product under different additions of fly ash are indicated in Table 5, the test results of the 1 h water absorption rate are indicated in Table 6, the test results of bulk densities are indicated in Table 7, and the leaching contents of the heavy metals are indicated in Table 8.

(16) TABLE-US-00005 TABLE 5 test results of bulk densities of the lightweight aggregates in the fly ash/coal gangue/cement system 15% cement 25% cement 40% cement Fly bulk bulk bulk ash/coal density/ Density density/ Density density/ Density gangue kg .Math. m.sup.3 level kg .Math. m.sup.3 level kg .Math. m.sup.3 level 9:1 730 800 768 800 783 800 8:2 763 800 775 800 790 800 7:3 790 800 798 800 810 900 6:4 820 900 824 900 840 900 5:5 839 900 843 900 862.5 900 4:6 842 900 850 900 889 900 3:7 910 1000 921 1000 943 1000 2:8 931 1000 933 1000 962.5 1000 1:9 946 1000 951 1000 1000 1000

(17) TABLE-US-00006 TABLE 6 test results of 1 h water absorption rate of the lightweight aggregates with different cement contents in the fly ash/coal gangue system Fly ash/ Cement 15% Cement 25% Cement 40% coal gangue (uncured) (cured 7 d) (cured 2 d) 9:1 28.2 8:2 29.81 7:3 28.57 24.38 28.11 6:4 23.62 23 25.34 5:5 23.14 22 22.69 4:6 23 21.19 19.82 3:7 20.29 17.58 18.52 2:8 19.76 14.44 15.95 1:9 17.5 13.95

(18) TABLE-US-00007 TABLE 7 performance test results of the lightweight aggregates under different curing conditions in the fly ash/coal gangue/cement system Fly Bulk density/kg .Math. m.sup.3 Apparent density/kg .Math. m.sup.3 1 h water absorption rate/% ash/coal 2 d, 5 d, 2 d, 5 d, 2 d, 5 d, gangue RH75% RH100% RH75% RH100% RH75% RH100% 5:5 862.5 980.83 1578.00 1806.3 22.69 2.76 3:7 892.5 988.33 1800.00 1976.19 18.52 3.18 1:9 962.5 1000 1900.00 2036.34 14.43 5.46

(19) TABLE-US-00008 TABLE 8 leaching results of heavy metals under different contents of fly ash and coal gangue Fly ash/coal gangue As Pb Cd Cr Cu Ni Zn Mn 7:3 0.1 0.016 0.064 0.559 6:4 0.03 0.008 0.502 5:5 0.037 0.367 4:6 0.072 0.019 0.438 3:7 0.037 0.363 2:8 0.025 0.005 0.359 8:2 0.019 0.054 0.03 0.35 0.062 Environmental 0.1 0.3 0.03 0.2 1.0 0.2 1.0 1.0 limit * Notes: represents undetected in accordance with the standard Control Standard for Pollutants in Cement kilns, unit mg/L

(20) From the test results, it can be known that when coal gangue and fly ash are mixed, along with increase of the content of the fly ash, the bulk density of the lightweight aggregate decreases and the water absorption rate increases, which indicates that the addition of the fly ash can increase the hydration curing rate to some extent; and the decrease of the pollution parameters after curing indicates an effect on the environmental pollution. However, in order to ensure the quality of the lightweight aggregate building materials, it is preferred not to add too much fly ash.

(21) The above descriptions are about the preferred embodiments of the present disclosure but the present disclosure is not limited to the specific details of the above embodiments. Various simple variations made to the technical schemes or parameter settings in the present disclosure within the technical idea of the present disclosure shall fall within the scope of protection of the present disclosure.