A CO2 capture-mineralization integrated material and its preparation method and application

Abstract

The invention discloses a CO2 capture-mineralization integrated material and a preparation method and application thereof. The invention comprises the following steps: uniformly mixing fly ash, a mineralizing agent and an alkaline substance in a mass ratio of 1-10:1-4:0.5-2 to obtain a solid mixture, wherein the mass ratio of tetracalcium sulfoaluminate, dicalcium silicate and calcium sulfate dihydrate in the mineralizing agent is 10-20:5-10:70-80; uniformly mixing the solid mixture with water in a mass ratio of water to fly ash of 4-10:1 to obtain a solid-liquid mixture; reacting the solid-liquid mixture at 30-70°C in a sealed state isolated from air for 4-8 hours, separating the solid and liquid of the reaction product and drying the reaction product to obtain the product. The method of the present invention for preparing an integrated CO2 capture-mineralization material using fly ash activates active Al and Si in the fly ash to form minerals with a high specific surface area through the induced activation effect of a mineralizer and an alkaline substance, thereby increasing the CO2 diffusion capacity, improving the CO2 capture efficiency and the total amount of CO2 captured, and enabling the integrated CO2 capture-mineralization material to have excellent CO2 capture and in-situ mineralization capabilities.

Description

Technical Field

[0001] The present invention belongs to the technical field of carbon dioxide capture materials, and specifically relates to a CO2 capture-mineralization integrated material and a preparation method and application thereof. Background Art

[0002] The statements herein merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] In the existing carbon fixation technology, the fly ash modified material method mainly includes a mineralization process in the form of a slurry, and does not involve an adsorption-mineralization coupling method. Moreover, in this method, after a certain modification treatment, the fly ash reacts with CO2 gas in a slurry environment to generate stable carbonate minerals, such as calcium carbonate (CaCO3) or magnesium carbonate (MgCO3). However, this slurry reaction method not only has complex process, high cost and subsequent waste liquid treatment problems, but also the fly ash CaO content is low, and its mineralization efficiency has not been significantly improved. Therefore, although the slurry reaction method in the prior art has a certain application basis in the CO2 mineralization of fly ash modified materials, it still faces challenges in actual application such as high process complexity, high cost, difficulty in waste liquid treatment and suboptimal mineralization efficiency.

[0004] Existing fly ash modification methods (alkaline cellulose, sodium chloride solution, organic amine solvent, ammonium ion solution, high pressure and high temperature, etc.) often require high energy consumption or high-cost raw materials, which greatly reduces economic efficiency.

[0005] The CO2 mineralization material based on fly ash modification does not involve the development of adsorption performance, and does not solve the problem of carbonized film generated by the mineralization reaction hindering the continuation of the reaction, resulting in no significant improvement in mineralization efficiency, which limits its application.

[0006] The carbon fixation reaction of modified fly ash is a slurry reaction, which requires precise control of multiple parameters, including slurry pH, temperature, and CO2 flow rate, to ensure efficient reaction. This complex process not only requires a high degree of coordination between equipment and operating techniques, but also increases the difficulty of process management.

[0007] The wastewater generated during the carbon fixation reaction needs to be treated to avoid negative impacts on the environment. Wastewater treatment not only increases the complexity of the process but also increases production costs. Summary of the Invention

[0008] To address the shortcomings of existing technologies, the present invention aims to provide an integrated CO2 capture-mineralization material, its preparation method, and its application. This approach aims to improve the efficiency of fly ash in the CO2 capture-mineralization process, achieve green, value-added utilization of fly ash, and address solid waste disposal issues.

[0009] In order to achieve the above object, the present invention is implemented through the following technical solutions:

[0010] In a first aspect, the present invention provides a method for preparing a CO2 capture-mineralization integrated material, comprising the following steps:

[0011] The fly ash, the ore-starting agent and the alkaline substance are uniformly mixed in a mass ratio of 1-10:1-4:0.5-2 to obtain a solid mixture, wherein the mass ratio of tetracalcium sulfoaluminate, dicalcium silicate and calcium sulfate dihydrate in the ore-starting agent is 10-20:5-10:70-80;

[0012] The solid mixture is mixed evenly with water, with the mass ratio of water to fly ash being 4-10:1, to obtain a solid-liquid mixture;

[0013] The solid-liquid mixture is reacted at 30-70°C in a sealed and airtight state for 4-8 hours, and the reaction product is separated into solid and liquid and dried to obtain the product.

[0014] In some embodiments, the alkaline substance is calcium oxide, sodium hydroxide, or sodium silicate.

[0015] Preferably, the alkaline substance is calcium oxide.

[0016] In some embodiments, in the ore-introducing agent, the mass ratio of tetracalcium sulfoaluminate, dicalcium silicate and calcium sulfate dihydrate is 15-20:7-10:70-80.

[0017] Preferably, in the ore-introducing agent, the mass ratio of tetracalcium sulfoaluminate, dicalcium silicate and calcium sulfate dihydrate is 16:9:75.

[0018] In some embodiments, the reaction is continuously stirred at a rate of 400-800 r / min at 30-70° C. for 4-8 hours to ensure uniform reaction of the mixture and sufficient activation of the mineral components.

[0019] In some embodiments, the drying temperature is 40-50° C. Minerals are easily decomposed at high temperatures. When a lower temperature is used for drying, the stable existence of the minerals is ensured while the sample is dried.

[0020] In some embodiments, the process further includes crushing and screening the product obtained after drying, and passing the crushed product through a 200-mesh sieve to remove larger particles and obtain modified fly ash with uniform particle size.

[0021] In a second aspect, the present invention provides a CO2 capture-mineralization integrated material prepared by the preparation method.

[0022] In a third aspect, the present invention provides the use of the CO2 capture-mineralization integrated material in CO2 capture and mineralization.

[0023] The beneficial effects achieved by one or more embodiments of the present invention are as follows:

[0024] The method of the present invention for preparing an integrated CO2 capture-mineralization material using fly ash activates active Al and Si in the fly ash to form minerals with a high specific surface area, such as ettringite and hydrated calcium silicate gel, and other easily mineralized minerals, through the induced activation effect of a mineralizing agent and an alkaline substance. These minerals form a flower cluster structure, which increases the diffusion capacity of CO2, improves the capture efficiency and the total amount of CO2 captured, and enables the integrated CO2 capture-mineralization material to have excellent CO2 capture and in-situ mineralization capabilities.

[0025] The CO2 capture-mineralization integrated material has excellent CO2 capture and mineralization capabilities. Each gram of CO2 capture-mineralization material can capture and mineralize up to 50 mg of CO2.

[0026] The generated nanoscale calcium carbonate (mainly calcite) has excellent mechanical and filling properties, ensuring the feasibility of subsequent product applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0028] Figure 1 is a process flow chart of an embodiment of the present invention;

[0029] Figure 2 This is an electron microscope image of the sample in Example 1 of the present invention. DETAILED DESCRIPTION

[0030] It should be noted that the following detailed description is illustrative and is intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those skilled in the art to which the present invention belongs.

[0031] The present invention will be further described below with reference to the embodiments.

[0032] Example 1

[0033] like Figure 1As shown, 2g of fly ash, 2g of a mineralizing agent (the mineralizing agent comprises 16% tetracalcium sulfoaluminate, 9% dicalcium silicate, and 75% calcium sulfate dihydrate, with % being mass percentages), and 1g of calcium oxide are uniformly mixed to obtain a solid mixture. 40g of water is then poured into a beaker, and the solid mixture is then poured into the beaker. The beaker is sealed to isolate the air and placed in a constant temperature and constant speed magnetic stirring oil bath at 50°C and 550 r / min for 6 hours. The slurry is filtered, dried, and passed through a 200-mesh sieve to obtain a powdery CO2 capture-mineralization integrated material.

[0034] The test obtained the excitation ratio of Al in fly ash, the mass ratio of AFt generated, the specific surface area, pore volume and average pore diameter.

[0035] 2g of CO2 capture-mineralization integrated material was placed in a mixed atmosphere (15% CO2, 85% N2, 90°C, and a moisture content of 8.4g / kg dry air) and reacted for two hours. The material was then taken out and dried at low temperature to obtain the carbon fixation amount.

[0036] Take 10mg of sample for TG-DTG test to get the specific content of mineral components. Nano calcium carbonate is observed by electron microscope. Figure 2 shown.

[0037] Example 2

[0038] 5g of fly ash, 2g of a mineralizing agent (the mineralizing agent comprises 16% tetracalcium sulfoaluminate, 9% dicalcium silicate, and 75% calcium sulfate dihydrate, with % being percentages by mass), and 1g of calcium oxide were mixed to obtain a solid mixture. 64g of water was added to a beaker, and the solid mixture was then poured into the beaker. The mixture was sealed to isolate the air and placed in a constant temperature and constant speed magnetic stirring oil bath at 70°C and 450 rpm for 4 hours. The slurry was filtered, dried, and passed through a 200-mesh sieve to obtain an integrated CO2 capture and mineralization material.

[0039] The test obtained the excitation ratio of Al in fly ash, the mass ratio of AFt generated, the specific surface area, pore volume and average pore diameter.

[0040] 2g of the integrated CO2 capture-mineralization material was placed in a mixed atmosphere (15% CO2, 85% N2, 70°C, with a moisture content of 8.4g / kg dry air) for two hours. The material was then removed and dried at low temperature, and the carbon sequestration was measured.

[0041] Example 3

[0042] Mix 7g of fly ash, 2g of a mineralizing agent (16% tetracalcium sulfoaluminate, 9% dicalcium silicate, and 75% calcium sulfate dihydrate, where % is by mass), and 1g of calcium oxide to obtain a solid mixture. Pour 80g of water into a beaker, seal it to isolate it from air, and place it in a magnetically stirred oil bath at a constant temperature and speed of 30°C and 650 rpm for 8 hours. The slurry is filtered, dried, and passed through a 200-mesh sieve to obtain a powdery integrated CO2 capture and mineralization material.

[0043] The test obtained the excitation ratio of Al in fly ash, the mass ratio of AFt generated, the specific surface area, pore volume and average pore diameter.

[0044] 2g of the integrated CO2 capture and mineralization material was placed in a mixed atmosphere (15% CO2, 85% N2, 30°C, and a moisture content of 5.3g / kg dry air) and allowed to react for two hours. The material was then removed and dried at low temperature, and the carbon sequestration was measured.

[0045] Comparative Example 1

[0046] The difference from Example 3 is that the ore-introducing agent is omitted, and the rest is the same as Example 3.

[0047] Comparative Example 2

[0048] The difference from Example 3 is that the ore-introducing agent is all calcium sulfate dihydrate, and the rest is the same as Example 3.

[0049] Comparative Example 3

[0050] The difference from Example 3 is that calcium oxide is omitted, and the rest is the same as Example 3.

[0051] Table 1 Performance comparison of Examples 1-3

[0052]

[0053]

[0054] As shown in Table 1, the prepared CO2 capture-mineralization integrated material successfully stimulated the active elements in fly ash to generate easily mineralized minerals, and has good CO2 adsorption-mineralization performance.

[0055] Table 2 Comparative performance of Example 3 and Comparative Examples 1-3

[0056] Test items Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Excitation ratio of Al in fly ash / % 9.81 0 2.30 1.60 The mass percentage of ettringite generated / % 7.24 0 1.12 1.26 <![CDATA[Specific surface area / (m 2 / g)]]> 3.61 1.22 2.15 4.32 <![CDATA[Pore volume / (cm 3 / g)]]> 0.02 0.01 0.01 0.02 Average pore size / nm 24.08 29.18 22.16 17.33 Carbon fixation / (mg / g modified fly ash) 50 0 8 6

[0057] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A method for preparing a CO2 capture-mineralization integrated material, characterized by: The steps include: The fly ash, the ore-starting agent and the alkaline substance are uniformly mixed in a mass ratio of 1-10:1-4:0.5-2 to obtain a solid mixture, wherein the mass ratio of tetracalcium sulfoaluminate, dicalcium silicate and calcium sulfate dihydrate in the ore-starting agent is 10-20:5-10:70-80; The solid mixture is mixed evenly with water, with the mass ratio of water to fly ash being 4-10:1, to obtain a solid-liquid mixture; The solid-liquid mixture is reacted at 30-70°C in a sealed and airtight state for 4-8 hours, and the reaction product is separated into solid and liquid and dried to obtain the product.

2. The method for preparing the integrated CO2 capture-mineralization material according to claim 1, characterized in that: The alkaline substance is calcium oxide, sodium hydroxide or sodium silicate.

3. The method for preparing the integrated CO2 capture-mineralization material according to claim 2, characterized in that: The alkaline substance is calcium oxide.

4. The method for preparing the integrated CO2 capture-mineralization material according to claim 1, characterized in that: In the ore-introducing agent, the mass ratio of tetracalcium sulfoaluminate, dicalcium silicate and calcium sulfate dihydrate is 15-20:7-10:70-80.

5. The method for preparing the integrated CO2 capture-mineralization material according to claim 4, characterized in that: In the ore-introducing agent, the mass ratio of tetracalcium sulfoaluminate, dicalcium silicate and calcium sulfate dihydrate is 16:9:

75.

6. The method for preparing the integrated CO2 capture-mineralization material according to claim 1, characterized in that: The reaction was continued with stirring at a rate of 400-800 r / min.

7. The method for preparing the integrated CO2 capture-mineralization material according to claim 1, characterized in that: The drying temperature is 40-50°C.

8. The method for preparing the integrated CO2 capture-mineralization material according to claim 1, characterized in that: The method also includes a process of crushing and screening the product obtained after drying, and passing the crushed product through a 200-mesh sieve.

9. A CO2 capture-mineralization integrated material, characterized by: Prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the CO2 capture-mineralization integrated material according to claim 9 in CO2 capture and mineralization.

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