Co-mineralization by utilizing bulk solid wastes 2 Method for producing building materials
Technical Field
The invention relates to the field of IPC classification C04B28/00, in particular to CO-mineralization of CO by utilizing bulk solid wastes 2 A method of making a building material.
Background
With the development of economy, the urbanization of the living environment of people is accelerated, industries such as coal, electric power and building are rapidly developed, and meanwhile, the quality of a large amount of solid wastes discharged in related fields is also increased year by year. The occurrence of the bulk solid wastes not only occupies a large amount of land resources for storage, but also causes serious pollution to the environment, water bodies and the like due to the complex components in the bulk solid wastes.
At present, the solid waste recycling means mainly focuses on building material utilization, and most of the existing solid waste building material utilization means are high in energy consumption. For example, in the prior art (CN104072193B), a foamed ceramic material based on silicon-aluminum-containing solid waste and a method for preparing a fireproof heat-insulating board are disclosed, wherein silicon-aluminum-containing solid waste is used as a raw material, and a small amount of calcium-containing ore, cosolvent and foaming agent are added to prepare the foamed ceramic material and the fireproof heat-insulating board 2 . The prior art (CN106915938B) discloses a system and a method for preparing a sulphoaluminate ultra-high water filling material by using industrial solid wastes, wherein silicon-aluminum-iron-based solid wastes such as coal gangue and the like and calcium sulfate-based solid wastes such as desulfurized gypsum and the like are mainly used as raw materials, and a matrix material is prepared by processes such as raw material grinding, homogenization, sintering, clinker grinding and the like, wherein the processes such as grinding, sintering and the like used in the method are high in energy consumption. In addition, in the prior art, researches on resource recycling are less in the aspects of synergic mineralization of a large amount of solid wastes and carbon dioxide, the strength of a building material product prepared through mineralization reaction is generally low, auxiliary cementing materials such as cement and the like are additionally added to ensure the service performance, and the production process of the cementing materials is high in carbon emission.
Therefore, the CO-mineralization of the bulk solid waste and the CO mineralization of the CO with the bulk solid waste, which have the advantages of low energy consumption and low carbon emission, can effectively utilize the synergistic effect of the bulk solid waste and the carbon dioxide, and the prepared building material has excellent mechanical strength, is urgently needed 2 A method of making a building material.
Disclosure of Invention
To solve the above problems, the first aspect of the present inventionProvides a method for CO-mineralizing CO by utilizing bulk solid wastes 2 The method for preparing the building material comprises the steps of preparing a solid-waste mixture, carrying out mineralization reaction, carrying out hydrothermal reaction and blocking molding; the mineralization reaction sequence is before or after the block forming step; the solid waste mixture comprises solid waste and water.
As a preferred scheme, the sequence of the mineralization reaction is before the step of forming into blocks, and the method for preparing the building material sequentially comprises the following steps: (1) preparing a solid waste mixture; (2) carrying out mineralization reaction; (3) forming into blocks; (4) and (4) carrying out hydrothermal reaction.
As a preferable scheme, the solid content of the solid waste mixture is adjusted between the mineralization reaction step and the blocking forming step; the solid content of the solid waste mixture is regulated specifically as follows: supplementing solid waste or supplementing solid waste and gypsum into the solid waste mixture;
as a preferable scheme, the mass ratio of water to solid waste in the solid waste mixture prepared in the step (1) is 1: 1-10: 1.
As a preferred scheme, the sequence of the mineralization reaction is positioned after the block molding step, and the method for preparing the building material sequentially comprises the following steps: (1) preparing a solid waste mixture; (2) forming into blocks; (3) carrying out mineralization reaction; (4) and (4) carrying out hydrothermal reaction.
As a preferable scheme, the blocking molding is casting vibration molding in a mold, and the solid content of a solid-waste mixture used for the blocking molding is 50-85%; the blocking forming is compression forming, and the solid content of the solid waste mixture used for the blocking forming is 65-95%.
In the application, the solid-waste mixture for blocking molding can be the solid-waste mixture prepared in the step (1) or the solid-waste mixture after solid content is adjusted according to different mineralization reaction sequences.
As a preferable scheme, the blocking molding is casting vibration molding in a mold, and the solid waste mixture used for the blocking molding also comprises gypsum.
As a preferred scheme, the element composition in the solid waste mixture satisfies the following conditions:
n(CaO)≥4n(Al 2 O 3 )+1.5n(SiO 2 )-n(CaSO 4 );
wherein n (CaO) is the molar weight of Ca element in oxide composition which can generate carbonization reaction in the solid waste; n (Al) 2 O 3 ) Is the molar weight of Al element in the solid waste calculated by oxide composition; n (SiO) 2 ) Is the mole amount of Si element in the solid waste by oxide composition; n (CaSO) 4 ) Is CaSO in gypsum 4 The molar amount of (c).
As a preferable scheme, the content of the gypsum is 0.1-5% of the total mass of the solid waste in the solid waste mixture.
In the application, by limiting the addition of the gypsum, not only is the cooperative utilization of bulk solid wastes and waste gas effectively realized, but also the mechanical property of the prepared building material is effectively improved, so that the building material has excellent antioxidant strength and CO 2 And (4) absorption effect. The applicant speculates that: the addition of the gypsum with proper content can accelerate the forming and demoulding efficiency of the mixture in the process of the blocking forming of the solid-waste mixture, enhance the connecting strength of the content cement and the solid waste after the mixing forming, and promote the formed micro-pores to effectively generate the conversion action of silver grains and cracks, thereby improving the upper limit of the pressure bearing of the building material under the action of the extreme external force. However, the addition amount of gypsum needs to be kept within a proper range, and if the addition amount of gypsum is too large, so that the optimization of the types of final products is not facilitated, and the product performance is influenced.
As a preferable scheme, the blocking molding is press molding, and the element composition in the solid waste mixture meets the following requirements:
n(CaO)≥4n(Al 2 O 3 )+1.5n(SiO 2 );
wherein, n (CaO) is the molar weight of Ca element in oxide composition which can generate carbonization reaction in the solid waste; n (Al) 2 O 3 ) Is the molar weight of Al element in the solid waste by the composition of oxides; n (SiO) 2 ) Is the mole amount of Si element in the solid waste based on the oxide composition.
As a preferable scheme, the solid waste is at least one of carbide slag, magnesium slag, phosphorus slag, steel slag, furnace ash, iron slag, gasified slag, fly ash, slag ash, bottom ash, fly ash, red mud, construction waste, waste cement, tailings and ore raw materials.
As a preferred scheme, the mineralization reaction adopts a material containing CO 2 Said gas containing CO 2 CO in the gas of (2) 2 The volume fraction of the mineral is 8-100%, the mineralization reaction time is 30-240 min, and the mineralization reaction temperature is 20-120 ℃.
Preferably, the catalyst contains CO 2 The gas is at least one of coal-fired power plant flue gas, lime kiln flue gas, steel plant flue gas, chemical plant flue gas, cement plant flue gas and gas after carbon capture and analysis.
As a preferred scheme, the hydrothermal reaction is specifically operated as follows: and placing the blank body to be subjected to the hydrothermal reaction into a reaction kettle, vacuumizing, introducing high-temperature water vapor to perform the hydrothermal reaction, wherein the reaction temperature is 120-240 ℃, and the reaction time is 4-12 hours.
As a preferable scheme, the mineralization pressure in the mineralization reaction process is 0.3-2 MPa.
Preferably, the pressure in the hydrothermal reaction process is 1-3 MPa.
The second aspect of the invention provides the CO-mineralization method by utilizing the bulk solid waste 2 Application of method for preparing building material, including CO-mineralizing CO by utilizing bulk solid waste 2 Method for producing building materials, production of building materials and CO 2 And the recycling process of (2).
Has the advantages that:
1. according to the preparation method of the building material, through multi-source bulk solid waste compounding and material design, active calcium elements in solid waste can be fully utilized to capture CO in waste gas 2 And the activity of each element in a large amount of solid wastes can be fully utilized from the thermodynamic angle, so that the building material with extremely high cost performance is obtained.
2. The preparation method of the building material provided in the application can simultaneously solve the treatment and disposal problems of bulk solid wastes and CO by means of extremely low carbon emission 2 The method has the advantages of solving the problem of trapping and utilizing, reducing energy consumption, being suitable for the existing building material preparation production line, having simple flow, having general equipment and rich appearance of strong products, and the like.
3. The present application is not particularly limited to CO 2 Gas source and concentration, CO saving 2 Energy consumption and cost in the trapping process are reduced, high carbon emission raw materials commonly used by building materials such as cement and gravel are hardly added in the formula design, and the carbon emission of the whole process is reduced from the raw material end.
4. According to the preparation method of the building material, the addition amount of gypsum is limited and the cement proportion is controlled, so that the synergistic utilization of a large amount of solid wastes and waste gas is effectively realized, the mechanical property of the prepared building material is effectively improved, and the building material has excellent antioxidant strength and CO (carbon monoxide) 2 The absorption effect can be further applied to various industrial scenes, such as steel, electric power, coal chemical industry, cement, glass, ceramics and the like, and has wide applicability.
Detailed Description
The performance tests of the test block in the following embodiments and comparative examples comprise carbon dioxide absorptivity and compressive strength, wherein the carbon dioxide absorptivity is the percentage of the mass of carbon dioxide absorbed by solid wastes in the mass of the test block, the content of carbon dioxide absorbed by solid wastes is obtained by testing a TG/DTG curve of a mineralized product, the content of carbon dioxide absorbed by solid wastes is 550-850 ℃, and the mass of the test block is the mass of the mineralized product at 105 ℃; the compressive strength was measured according to GBT4111-2013 "test methods for concrete blocks and bricks".
Solid waste information in examples and comparative examples: the solid waste 1 is from a fertilizer-mixing and certain salt coal chemical plant and is a mixture of gasified slag, carbide slag and large slag ash; the solid waste 2 comes from a certain domestic garbage incineration plant in Suzhou and is a mixture of garbage incineration bottom ash and fly ash.
CO-CONTAINING COMPARATIVE EXAMPLES AND COMPARATIVE EXAMPLES 2 Composition information (volume fraction) of the gas of (2): the gas a comes from tail gas of a fertilizer-mixing and salt-coal chemical plant; the gas b is CO generated by flue gas of a certain domestic garbage incineration plant in Suzhou after dust removal, desulfurization and denitrification and an organic amine method carbon laying device 2 A gas.
Gas composition
|
CO 2 |
N 2 |
SO x |
NO x |
VOCs
|
Gas a
|
76.5%
|
18.9%
|
2.3%
|
2%
|
0.3%
|
Gas b
|
98.6%
|
1.4%
|
0%
|
0%
|
0% |
Example 1
Example 1 in a first aspect, there is provided a method for CO-mineralizing CO using bulk solid waste 2 The method for preparing the building material comprises the following specific steps: (1) preparing a solid waste mixture; (2) carrying out mineralization reaction; (3) adjusting the solid content of the solid waste mixture; (4) forming into blocks; (5) and (4) carrying out hydrothermal reaction.
Embodiment mode S1-1:
(1) the solid waste 1 is prepared from the following fly ash in percentage by mass: carbide slag: mixing the large slag ash in a ratio of 4:5:1, recording as SW1, weighing 10 parts of SW1 and 10 parts of water, conveying the mixture into a reactor with a stirrer, and uniformly mixing to obtain a mixture 1; (2) introducing gas a into the mixture 1 at 60 ℃, wherein the mineralization reaction time is 120 min; (3) after the mineralization reaction is finished, supplementing 40 parts of SW1 into the reactor, and quickly stirring to obtain a mixture 2, wherein the solid content of the mixture 2 is 81.9%; (4) conveying the mixture 2 into a mould, performing compression molding under the pressure of 15MPa, and demolding to obtain a green body; (5) and (3) placing the demolded green body into a hydrothermal reaction kettle for reaction at the temperature of 180 ℃ for 8 hours.
Embodiment C1-1:
(1) the solid waste 1 is prepared from the following fly ash in percentage by mass: carbide slag: mixing the large slag ash in a ratio of 6:3:1, recording as SW2, weighing 10 parts of SW2 and 10 parts of water, conveying the mixture into a reactor with a stirrer, and uniformly mixing to obtain a mixture 3; (2) introducing gas a into the mixture 3 at 60 ℃, wherein the mineralization reaction time is 120 min; (3) after the mineralization reaction is finished, supplementing 40 parts of SW2 into the reactor, and quickly stirring to obtain a mixture 4, wherein the solid content of the mixture 4 is 81.9%; (4) conveying the mixture 4 into a mould, performing compression molding under the pressure of 15MPa, and demolding to obtain a green body; (5) and (3) placing the demolded green body into a hydrothermal reaction kettle for reaction at the temperature of 180 ℃ for 8 hours.
Embodiment mode S1-2:
(1) the solid waste 1 is prepared from the following components in percentage by mass: carbide slag: mixing large slag ash at a ratio of 4:5:1, recording as SW1, weighing 10 parts of SW1 and 10 parts of water, conveying the mixture into a reactor with a stirrer, and uniformly mixing to obtain a mixture 5; (2) introducing gas a into the mixture 5 at 100 ℃, wherein the mineralization reaction time is 40 min; (3) after the mineralization reaction is finished, supplementing 20 parts of SW1 and 0.4 part of gypsum into the reactor, and quickly stirring to obtain a mixture 6, wherein the solid content of the mixture 6 is 76.9%; (4) conveying the mixture 6 into a mold, pouring and vibrating for molding, and completing demolding when the green body has demolding strength to obtain a green body; (5) and (3) placing the demolded green body into a hydrothermal reaction kettle for reaction at the temperature of 200 ℃ for 6 hours.
Embodiment C1-2:
(1) the solid waste 1 is prepared from the following components in percentage by mass: carbide slag: mixing the large slag ash in a ratio of 6:3:1, recording as SW2, weighing 10 parts of SW2 and 10 parts of water, conveying the mixture into a reactor with a stirrer, and uniformly mixing to obtain a mixture 7; (2) introducing gas a into the mixture 1 at 100 ℃, wherein the mineralization reaction time is 40 min; (3) after the mineralization reaction is finished, supplementing 20 parts of SW1 and 0.4 part of gypsum into the reactor, and quickly stirring to obtain a mixture 8, wherein the solid content of the mixture 8 is 76.9%; (4) conveying the mixture 8 into a mold, pouring and vibrating for molding, and completing demolding when the green body has demolding strength to obtain a green body; (5) and (3) placing the demolded green body into a hydrothermal reaction kettle for reaction at the temperature of 200 ℃ for 6 hours.
The results of the performance testing of each embodiment in example 1 are shown in the following table:
name of test block
|
Carbon dioxide absorption rate (%)
|
Average compressive strength (Mpa)
|
S1-1
|
18.33
|
18.2
|
C1-1
|
16.71
|
9.23
|
S1-2
|
19.47
|
21.3
|
C1-2
|
16.24
|
10.32 |
In the above table, it can be found that the ratio of calcium oxide, silicon dioxide and aluminum oxide, which are components of the test block obtained by pressing the mineralized slurry into blocks or pouring the mineralized slurry into blocks for hydrothermal experiments, has a large influence on the carbon dioxide absorption rate and compressive strength of the test block. Comparing S1-1 and C1-1 with S1-2 and C1-2 respectively, when the proportion of the calcium oxide, the silicon dioxide and the aluminum oxide in the mixed raw materials meets the condition that n (CaO) is more than or equal to 4n (Al) 2 O 3 )+1.5n(SiO 2 ) Under the condition, the strength and the absorptivity of the final product are higher, because when the proportion of calcium oxide, silicon dioxide and aluminum oxide does not satisfy the formula, on one hand, the content of calcium oxide in the raw material is reduced, and the contact probability of carbon dioxide and the raw material is reduced in the mineralization reaction stage, so that the absorptivity of a sample to the carbon dioxide is lower; on the other hand, calcium oxide is reacted in the mineralization stage, and the residual calcium oxide cannot fully react with the silicon and aluminum to generate a strength enhanced phase (CSH/Aft/AFm), so that the compressive strength of the sample is greatly reduced.
Example 2
Example 2 in a first aspect, a CO-mineralization method using bulk solid waste is provided 2 The method for preparing the building material comprises the following specific steps: (1) preparing a solid waste mixture; (2)forming into blocks; (3) carrying out mineralization reaction; (4) and (4) carrying out hydrothermal reaction.
Embodiment mode S2-1:
(1) and (3) burning fly ash by using solid waste 2 in a mass ratio: mixing 3:2 of incineration bottom ash, recording as SW3, weighing 100 parts of SW3 and 20 parts of water, conveying the materials into a reactor with a stirrer, and uniformly mixing to obtain a mixed material 9, wherein the solid content of the mixed material 9 is 83.3%; (2) conveying the mixture 9 into a die for blocking forming, pressing and forming under the pressure of 15MPa to obtain a green blank, and completing demoulding when the green blank has demoulding strength; (3) placing the demolded green body into a reaction kettle, vacuumizing, introducing gas b, and carrying out a mineralization reaction at 40 ℃ for 180 min; and (4) after the mineralization reaction is finished, evacuating gas in the reaction kettle, vacuumizing again, and then introducing high-temperature steam to carry out hydrothermal reaction at the reaction temperature of 160 ℃ for 10 hours.
Embodiment C2-1:
(1) burning bottom ash by using solid waste 2 in a mass ratio: mixing the incineration fly ash 2:3, recording as SW4, weighing 100 parts of SW4 and 20 parts of water, conveying the materials into a reactor with a stirrer, and uniformly mixing to obtain a mixture 10, wherein the solid content of the mixture 10 is 83.3%; (2) conveying the mixture 10 to a die for blocking and forming, pressing and forming under the pressure of 15MPa to obtain a green blank, and completing demoulding when the green blank has demoulding strength; (3) placing the demolded green body into a reaction kettle, vacuumizing, introducing gas b, and carrying out a mineralization reaction at 40 ℃ for 180 min; and (4) after the mineralization reaction is finished, evacuating gas in the reaction kettle, vacuumizing again, and then introducing high-temperature steam to carry out hydrothermal reaction at the reaction temperature of 160 ℃ for 10 hours.
Embodiment mode S2-2:
(1) burning bottom ash by using solid waste 2 in a mass ratio: mixing the incineration fly ash with the ratio of 3:2, recording as SW3, weighing 30 parts of SW3, 15 parts of water and 0.2 part of gypsum, conveying the materials into a reactor with stirring, and uniformly mixing to obtain a mixture 11, wherein the solid content of the mixture 11 is 66.67%; (2) conveying the mixture 11 into a mold, pouring and vibrating for molding, and completing demolding when the green body has demolding strength to obtain a green body; (3) placing the demolded green body into a reaction kettle, vacuumizing, introducing gas b, and carrying out a mineralization reaction at the reaction temperature of 80 ℃ for 80 min; (4) after the mineralization reaction is finished, evacuating the gas in the reaction kettle, vacuumizing again, and then introducing high-temperature water vapor to carry out hydrothermal reaction at the reaction temperature of 140 ℃ for 12 hours.
Embodiment C2-2:
(1) burning bottom ash by using solid waste 2 in a mass ratio: mixing the incineration fly ash 2:3, recording as SW4, weighing 30 parts of SW1, 15 parts of water and 0.2 part of gypsum, conveying the materials into a reactor with a stirrer, and uniformly mixing to obtain a mixture 12, wherein the solid content of the mixture 12 is 66.67%; (2) conveying the mixture 12 into a mold, pouring and vibrating for molding, and completing demolding when the green body has demolding strength to obtain a green body; (3) placing the demolded green body into a reaction kettle, vacuumizing, introducing gas b, and carrying out a mineralization reaction at the reaction temperature of 80 ℃ for 80 min; (4) after the mineralization reaction is finished, evacuating the gas in the reaction kettle, vacuumizing again, and then introducing high-temperature water vapor to carry out hydrothermal reaction at the reaction temperature of 140 ℃ for 12 hours.
The results of the performance testing of each embodiment in example 2 are shown in the following table:
name of test block
|
Carbon dioxide absorption rate (%)
|
Average compressive strength (MPa)
|
S2-1
|
15.43
|
18.47
|
C2-1
|
11.01
|
7.23
|
S2-2
|
16.01
|
17.94
|
C2-2
|
12.55
|
9.71 |
From the above table, it can be found that, although the solid waste raw material is changed, the influence of the proportions of calcium oxide, silicon dioxide and aluminum oxide on the compression strength and carbon dioxide absorption rate of the test block is the same. As long as the proportion of calcium oxide, silicon dioxide and aluminum oxide in the mixed raw materials satisfies n (CaO) is more than or equal to 4n (Al) 2 O 3 )+1.5n(SiO 2 )-n(CaSO 4 ) In the case of no gypsum in the solid waste mixture, n (CaSO) 4 ) 0), the strength and absorption of the final product will be high, which also proves that the rule applies to various scenarios.
Comparative example 1
Comparative example 1 in a first aspect, there is provided a CO-mineralisation process using bulk solid waste 2 The method for preparing the building material comprises the following specific steps:
(1) burning fly ash by using solid waste in a mass ratio: mixing the incineration bottom ash in a ratio of 6:4, recording as SW2-1, weighing 100 parts of SW1 and 20 parts of water, conveying the mixture into a reactor with a stirrer, and uniformly mixing to obtain a mixture 13; (2) conveying the mixture 13 into a die for blocking forming, pressing and forming under the pressure of 15MPa to obtain a green blank, and completing demoulding when the green blank has demoulding strength; (3) and (3) putting the demolded green body into a reaction kettle, vacuumizing, introducing gas b, and performing mineralization reaction at the reaction temperature of 40 ℃ for 180 min.
Comparative example 2
(1) And (3) burning fly ash by using solid waste 2 in a mass ratio: mixing the incineration bottom ash in a ratio of 6:4, recording as SW2-1, weighing 100 parts of SW1 and 20 parts of water, conveying the mixture into a reactor with a stirrer, and uniformly mixing to obtain a mixed material 14; (2) conveying the mixture 14 to a die for blocking and forming, and pressing and forming under the pressure of 15MPa to obtain a green blank, and completing demoulding when the green blank has demoulding strength; (3) and (3) putting the demolded green body into a reaction kettle, vacuumizing, and introducing high-temperature steam to perform hydrothermal reaction at the temperature of 160 ℃ for 10 hours.
Name of test block
|
Carbon dioxide absorption rate (%)
|
Average compressive strength (MPa)
|
Example 2-S2-1
|
15.43
|
18.47
|
Comparative example 1
|
14.89
|
5.23
|
Comparative example 2
|
-
|
16.31 |
It is understood from the comparative examples and comparative examples that the carbon fixation ratio of the test block subjected to only the mineralization reaction is guaranteed, but the strength of the test block after the reaction is low because the mineralized product is mainly platy calcite, and although some pores are filled, a small amount of pores are formed among crystals by printing and dyeing, so that microcracks are easily generated, and the strength of the mineralized test block is low. The compression strength of the product to carbon dioxide after hydrothermal treatment is higher than that of the product only mineralized, because CSH is generated by hydrothermal treatment and is in a gel shape, and can be used as a binder to be filled between crystal phases, the strength of the product is greatly improved; however, the strength of the test piece is lower than that of the test piece of the example only, because the crystal lattice energy of the hydrothermal reaction is reduced and the hydrothermal reaction is promoted to be more sufficient because the plate-shaped calcium carbonate generated by mineralization is used as an impurity phase in the hydrothermal reaction stage.