Preparation method and application of CO2 adsorbent based on industrial solid waste

Abstract

The invention relates to a preparation method and application of a CO2 adsorbent based on industrial solid waste, the preparation method comprises the following steps: firstly, pretreating a calcium-based precursor and a support material precursor, and mixing and drying the pretreated calcium-based precursor and support material precursor to obtain a mixture; and calcining the mixture to obtain the CO2 adsorbent with the two-phase framework. Wherein the supporting material precursor comprises a first metal oxide and a second metal oxide which are mixed, and the first metal oxide is aluminum oxide contained in industrial solid waste. After calcination, a thermodynamically stable calcium-base-containing biphase framework is generated, the pore structure and crystal stability of the CO2 adsorbent are effectively optimized, the CO2 adsorbent can be produced on a large scale, the material performance can be guaranteed, the adsorption capacity and cycle life of the CO2 adsorbent are both improved, and meanwhile, due to recycling of industrial solid waste, the CO2 adsorbent has the advantages of environmental protection and environmental protection. The economical efficiency and the environmental protection property are further improved.

Description

Technical Field

[0001] The present invention relates to the technical field of adsorption material preparation, and in particular to a preparation method and application of a CO2 adsorbent based on industrial solid waste. Background Art

[0002] With the development of industry, the demand for CO2 capture and resource utilization is growing. Currently, flue gas CO2 capture technologies primarily include chemical absorption, physical adsorption, membrane separation, and solid adsorbent methods. Among these, solid adsorbents offer advantages such as high adsorption capacity, rapid adsorption rate, low regeneration energy consumption, minimal equipment corrosion, and excellent recyclability, making them a highly promising flue gas CO2 capture technology.

[0003] However, on the one hand, although the existing preparation methods can produce solid adsorption materials with excellent performance on a laboratory scale, these solid adsorption materials usually exhibit excellent adsorption performance under laboratory conditions, but still face the problem of high costs when produced on a large scale industrial basis. In addition, laboratory preparation usually adopts small-batch, multi-step synthesis methods, while industrial production needs to consider process stability, equipment compatibility and production efficiency. Existing methods are often difficult to directly scale up, and are prone to problems such as uneven product performance and decreased yield.

[0004] On the other hand, industrial solid wastes such as fly ash and aluminum slag are rich in active ingredients and can theoretically serve as inexpensive raw materials for adsorption materials. However, current utilization of these industrial solid wastes is mostly through low-value landfill or simple construction material conversion, failing to fully realize their adsorption potential. The utilization rate of industrial solid waste generated annually in my country is low, and it is not effectively converted into adsorbent raw materials. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the defects in the prior art, thereby providing a preparation method and application of a CO2 adsorbent based on industrial solid waste.

[0006] To achieve the above object, the present invention adopts the following technical solutions: A preparation method and application of a CO2 adsorbent based on industrial solid waste, comprising the following steps: pre-treating a calcium-based precursor and a support material precursor, and mixing and drying the treated calcium-based precursor and the support material precursor to obtain a mixture; calcining the mixture to obtain a CO2 adsorbent having a dual-phase skeleton; The support material precursor includes a mixed first metal oxide and a second metal oxide, and the first metal oxide is aluminum oxide contained in industrial solid waste.

[0007] Furthermore, the second metal oxide is ZrO2; The dual-phase skeleton is formed by combining a Ca-Al skeleton and a Ca-Zr skeleton.

[0008] Furthermore, the calcium-based precursor is any one of organic calcium and inorganic calcium or a combination of both; The industrial solid waste is any one of fly ash, aluminum slag and steel slag.

[0009] Furthermore, the calcination includes low-temperature pre-calcination and high-temperature final calcination performed sequentially.

[0010] Furthermore, the temperature of the low-temperature pre-calcination is 650-750°C, the heating rate is 2-8°C / min, and the calcination time is 2-4h; The temperature of the high-temperature final calcination is 800-900° C., the heating rate is 2-8° C. / min, and the calcination time is 2-4 hours.

[0011] Furthermore, the mass percentages of the substances in the mixture are: 70-84% of the calcium-based precursor, 15-29% of the first metal oxide, and 1-3% of the second metal oxide.

[0012] Furthermore, the preprocessing specifically includes the following steps: Step S1, adjusting the calcium-based precursor and the support material precursor to set standards, wherein the set standards include a first set size of the calcium-based precursor, a second set size of the support material precursor, and a set impurity ratio of the support material precursor; Step S2: wet-mixing the calcium-based precursor under a set standard, the support material, and a solvent according to a set mixing ratio to obtain a mixture.

[0013] Furthermore, the specific steps of step S1 are: Grinding or crushing the calcium-based precursor to the first set size, grinding or crushing the support material precursor to the second set size; and / or The support material precursor is treated by acid washing, alkali washing or pre-desiliconization to reduce the impurity ratio.

[0014] Furthermore, the method further includes a forming and drying step before the staged calcination: shaping and drying the mixture to obtain particles having a third set size, wherein the shaping method is any one of extrusion shaping, spray granulation and compression molding, and the shaping condition is a working pressure of 5-10 MPa; or The invention also includes the steps of forming and drying after the staged calcination: The CO2 adsorbent is molded and dried to obtain particles of a third set size, wherein the molding method is any one of extrusion molding, spray granulation and compression molding, and the molding condition is a working pressure of 5-10 MPa.

[0015] Furthermore, it also includes quality inspection steps: Set up quality inspection points and conduct random inspections on the materials and / or process operating conditions involved in each step.

[0016] To achieve the above object, the present invention adopts the following technical solutions: An application of a CO2 adsorbent based on industrial solid waste, wherein the CO2 adsorbent is prepared by any one of the methods described above, and the CO2 adsorbent is used for carbon dioxide capture.

[0017] In summary, compared with the prior art, the present invention has at least the following beneficial effects: The present invention relates to a preparation method and application of a CO2 adsorbent based on industrial solid waste. First, a calcium-based precursor and a support material precursor are pretreated, and the treated calcium-based precursor and the support material precursor are mixed and dried to obtain a mixture; then the mixture is calcined to obtain a CO2 adsorbent with a dual-phase skeleton. The support material precursor includes a mixed first metal oxide and a second metal oxide, and the first metal oxide is aluminum oxide contained in industrial solid waste. After calcination, the calcium ions in the calcium base react with the first metal oxide and the second metal oxide to form a thermodynamically stable calcium-based dual-phase skeleton, effectively optimizing the pore structure and crystal stability of the CO2 adsorbent. The entire process is simple, so that the CO2 adsorbent can be mass-produced while ensuring material performance, achieving a dual improvement in the adsorption capacity and cycle life of the CO2 adsorbent. At the same time, due to the resource utilization of industrial solid waste, it can effectively reduce the cost of raw materials and reduce the pressure of solid waste disposal, further improving economic and environmental performance. DETAILED DESCRIPTION

[0018] The technical solution of the present invention will be described clearly and completely below. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0019] In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating positions or locations, are merely for the purpose of facilitating and simplifying the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0020] A method for preparing a CO2 adsorbent based on industrial solid waste comprises the following steps: pre-treating a calcium-based precursor and a support material precursor, and mixing and drying the treated calcium-based precursor and the support material precursor to obtain a mixture; The mixture is calcined to obtain a CO2 adsorbent having a dual-phase framework.

[0021] The support material precursor includes a first metal oxide and a second metal oxide. The first metal oxide is aluminum oxide and is obtained from industrial solid waste. The second metal oxide is doped into the first metal oxide. Preferably, the weight ratio of the components in the mixture is: 70-84% of the calcium-based precursor, 15-29% of the first metal oxide, and 1-3% of the second metal oxide.

[0022] Specifically, the first metal oxide Al2O3 contained in industrial solid waste is combined with the second metal oxide. Under the action of calcination, the first metal oxide Al2O3 reacts with the calcium-based precursor to form a high-melting-point calcium-aluminum spinel structure, forming a Ca-Al skeleton, which can provide the adsorbent with a high specific surface area and porosity, accelerate CO2 diffusion and contact efficiency, and optimize CO2 adsorption kinetics; the second metal oxide reacts with the Ca in the calcium-based precursor to form a calcium-aluminum spinel structure. 2+The reaction generates an orthorhombic structure embedded in the calcium-based matrix to form a Ca-X skeleton to form a CO2 diffusion channel, improve gas transmission efficiency, and limit CaO grain growth through the lattice anchoring effect, delaying the performance decay of the adsorbent in the cycle and further enhancing the performance of the CO2 adsorbent. It is worth noting that the metal X in the second metal oxide can be Zr, Ce, Ti, etc., which are not limited here. Therefore, in this application, by making Al ions and X ions coexist in the CaO matrix, the Ca-Al skeleton and the Ca-X skeleton dual-phase skeleton formed have a synergistic effect, that is, the Ca-Al skeleton provides high porosity, and the Ca-X skeleton maintains the diffusion channel, effectively optimizing the pore structure and crystal stability of the CO2 adsorbent. The whole process is simple, so that the CO2 adsorbent can be mass-produced and can ensure material performance, achieving a dual improvement in the adsorption capacity and cycle life of the CO2 adsorbent. At the same time, industrial solid waste is used instead of chemical raw materials, which not only reduces the raw material procurement cost, but also reduces the pressure of solid waste disposal, avoids the disposal cost of traditional solid waste landfill or storage, and further improves economy and environmental protection.

[0023] In certain embodiments of the present invention, the second metal oxide is ZrO2, that is, the dual-phase skeleton is a Ca-Al skeleton and a Ca-Zr skeleton. Specifically, Al2O3 reacts with CaO under calcination conditions to form a high-melting-point calcium aluminum spinel structure (Ca 12 Al 14 O 33 ), Al in the Ca-Al framework 3+ Occupy the lattice gaps and hinder Ca 2+ and O 2- The migration of ZrO2 can be inhibited, thereby inhibiting the agglomeration of CaO particles. In addition, the spinel structure can form a three-dimensional network skeleton in the CaO matrix with a high specific surface area and high porosity, which can provide a fast mass transfer channel for CO2 adsorption and optimize the CO2 adsorption kinetics. At the same time, ZrO2 reacts with CaO to form orthorhombic CaZrO3, whose Tamman temperature is as high as 2340 ° C, which is much higher than the sintering temperature of CaO. It can effectively maintain the structural stability of the adsorbent at high temperatures, and the CaZrO3 nanoparticles are embedded in the CaO matrix to form a "cage-like" porous structure, providing a CO2 diffusion channel with high mechanical strength and limiting the growth of CaO grains, preventing pore collapse at high temperatures, and further improving stability. Therefore, through Al 3+ and Zr 4+ They coexist in the CaO matrix, providing a stable dual-phase support skeleton (Ca-Al skeleton and Ca-Zr skeleton), effectively inhibiting the occurrence of sintering.

[0024] In certain embodiments of the present invention, the calcium-based precursor is any one or a combination of two of organic calcium or inorganic calcium, such as limestone, dolomite, calcium oxide, calcium acetate and egg shells; the industrial solid waste is waste containing Al2O3, which is any one of fly ash, aluminum slag and steel slag. Those skilled in the art can select and adjust according to actual application conditions, product requirements and quality requirements, and are not limited here. It is worth noting that fly ash, aluminum slag and steel slag containing Al2O3 are the industrial solid wastes that can be used in this application, otherwise they are not counted within the scope of industrial solid waste in this application.

[0025] In certain embodiments of the present invention, in order to further improve the stability of the CO2 adsorbent, the present application is improved from the traditional overall direct calcination to a staged calcination, that is, the calcination includes a low-temperature pre-calcination and a high-temperature final calcination carried out in sequence, and the calcination temperature of each stage is different. This is because the first metal oxide after pretreatment in the mixture contains certain organic residues and impurities such as bound water, and if these impurities are not removed, they will occupy the active sites of the adsorbent, affecting the performance and stability of the adsorbent. Therefore, a low-temperature pre-calcination is first performed. On the one hand, the lower calcination temperature can decompose and volatilize the organic impurities under relatively mild conditions, and the bound water will also evaporate under heat. On the other hand, it can trigger the initial Ca-Al / Ca-Zr solid-phase reaction to form a crystal nucleus prototype, which helps to grow into a stable crystal in a more orderly manner at high temperature to form a large-pore or mesoporous dual-phase skeleton. Then, a final calcination is performed at a high temperature. On the one hand, a stable crystal structure can be formed, and a stable crystal structure can further ensure the stability of the dual-phase skeleton, making it less likely to collapse or deform during the adsorption of CO2, thereby improving the stability and service life of the CO2 adsorbent, and on the other hand, it can promote the formation of micropores. Through staged calcination, the physical and chemical properties of the material, such as particle size, porosity and surface area, can be more precisely controlled. The surface area and porosity of the CO2 adsorbent directly affect the adsorption activity. For example, the larger the surface area, the more adsorption sites it can provide, and the richer the porosity, the more conducive it is to the diffusion and transmission of CO2 molecules inside the adsorbent, thereby directly improving the adsorption performance of CO2.

[0026] In certain embodiments of the present invention, the temperature of the low-temperature pre-calcination is 650-750°C, the heating rate is 2-8°C / min, and the calcination time is 2-4 hours. Preferably, the temperature of the low-temperature pre-calcination is 700°C, and the heating rate is 5°C / min. The temperature of the high-temperature final calcination is 800-900°C, the heating rate is 2-8°C / min, and the calcination time is 2-4 hours. Preferably, the temperature of the high-temperature final calcination is 900°C, and the heating rate is 5°C / min. It is worth noting that the heating rate needs to be strictly controlled during the calcination process to avoid defects in the dual-phase skeleton structure caused by excessively rapid temperature changes.

[0027] In certain embodiments of the present invention, the preprocessing specifically comprises the following steps: Step S1, adjusting the calcium-based precursor and the support material precursor to a set standard, wherein the set standard includes a first set size of the calcium-based precursor, a second set size of the support material precursor, and a set impurity ratio of the support material precursor; Step S2: wet-mixing the calcium-based precursor and the support material under the set standard with the solvent according to the set mixing ratio to obtain a mixture.

[0028] Specifically, step S1 includes a process for removing impurities from the support material precursor to improve the purity of the first metal oxide in the support material precursor and prevent impurities from interfering with subsequent solid-phase reactions and crystal growth. It also includes appropriately adjusting the particle size of the calcium-based precursor and the support material precursor to significantly improve the uniformity of the materials and ensure sufficient dispersion in the mixture. Preferably, the calcium-based precursor and the support material precursor are dispersed at the nanometer or micrometer scale. Furthermore, in step S2, wet mixing is selected to ensure uniform dispersion of the components and avoid the effects of electrostatic effects that may occur during dry mixing. Preferably, the solvent is water or ethanol, and grinding (e.g., ball milling) is performed during the mixing process to further ensure uniform dispersion of the components. It is worth noting that an appropriate amount of dispersant can be added during the wet mixing process to prevent agglomeration of the component particles and improve mixing uniformity. The type and amount of dispersant added can be selected and adjusted by those skilled in the art based on actual application conditions, product requirements, and quality requirements, and are not limited here.

[0029] In certain embodiments of the present invention, the specific steps of step S1 are: Grinding or crushing the calcium-based precursor to a first set size, and grinding or crushing the support material precursor to a second set size; and / or The support material precursor is treated by acid washing, alkaline washing or pre-desiliconization to a set proportion of impurities.

[0030] Among them, the first set size and the second set size are nanometer-scale or micrometer-scale, preferably nanometer-scale, to ensure that the calcium-based precursor and the support material precursor can be fully dispersed in the subsequent preparation process. In addition, the substances contained in the precursor that are unfavorable to the subsequent reaction are removed or their proportions are reduced to meet the impurity set ratio to reduce the impact of unfavorable substances on subsequent reactions. Those skilled in the art can select and adjust the values ​​of the first set size, the second set size and the impurity set ratio according to actual application conditions, product requirements and quality requirements, and are not limited here. It is worth noting that when the industrial solid waste is fly ash, pre-desiliconization treatment is required to make the Al2O3 content ≥40%.

[0031] In certain embodiments of the present invention, in order to enable the material to perform adsorption more effectively, the method further comprises the steps of shaping and drying.

[0032] This step can be optionally provided before the staged calcination, specifically: the mixture is molded and dried to obtain particles with a third set size, wherein the molding method is any one of extrusion molding, spray granulation and compression molding, and the molding condition is a working pressure of 5-10MPa.

[0033] This step can also be optionally performed after the staged calcination, specifically: the CO2 adsorbent is molded and dried to obtain particles of a third set size, wherein the molding method is any one of extrusion molding, spray granulation and compression molding, and the molding condition is a working pressure of 5-10MPa.

[0034] Preferably, the third set size is 3-6 mm. It is worth noting that during the molding process, an appropriate amount of binder can be added to improve the mechanical strength and wear resistance of the particles. The type and amount of the binder can be selected and adjusted by those skilled in the art based on actual application conditions, product requirements, and quality requirements, and are not limited here.

[0035] In some embodiments of the present invention, a quality inspection step is further included: Set up quality inspection points and conduct random inspections on the materials and / or process operating conditions involved in each step. Specifically, those skilled in the art can choose material testing to ensure the consistency and stability of product quality: such as the composition of the calcium-based precursor and the supporting material precursor, the first set size, the second set size, the impurity setting ratio, the ratio of each component in the mixture, the ratio of each component after molding, the structure of the CO2 adsorbent, the morphology of the CO2 adsorbent, and any one or more of the performance of the CO2 adsorbent, and select according to the actual application, product requirements and quality requirements; You can also choose to check whether the process operating conditions meet the control: such as the temperature of low-temperature pre-calcination, the heating rate of low-temperature pre-calcination, the calcination time of low-temperature pre-calcination, the temperature of high-temperature final calcination, the heating rate of high-temperature final calcination, the calcination time of high-temperature final calcination, and the working pressure of molding. Similarly, select according to the actual application, product requirements and quality requirements, and do not limit it here. It is worth noting that if the random inspection fails, the material needs to be re-prepared for operation.

[0036] In addition, the present invention also provides an application of a CO2 adsorbent prepared by the above-mentioned preparation method, which is specifically applied to carbon dioxide capture. Specifically, the CO2 adsorbent prepared in this application can undergo an acidification reaction with flue gas in a carbonation reactor to adsorb carbon dioxide. After adsorbing carbon dioxide, the CO2 adsorbent desorbs carbon dioxide by reducing the pressure or increasing the temperature in a regeneration reactor, and is regenerated. Through continuous carbonation / regeneration reaction cycles, carbon dioxide in flue gas can be captured.

[0037] In order to further illustrate the technical solution of the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention.

[0038] The reagents and materials used in the following examples were all commercially available. The following information is provided for the materials and instruments used in the examples of the present invention: limestone was purchased from Zhongbo Net, fly ash was finely powdered fly ash from a power plant in Hebei Province (with a SiO2 content of 50.37% and an Al2O3 content of 22.53%), industrial-grade sodium polyacrylate was purchased from Zhengzhou Lanxiang Chemical Products Co., Ltd., ethanol, polyethylene glycol, and Al2O3 were purchased from Sinopharm Chemical Reagent Co., Ltd., and ZrO2 was purchased from Conaici Technology Chemical Company.

[0039] Example 1 Step S1, air flow grinding limestone to 1 μm, air flow grinding fly ash to 1 μm, sieving after grinding, pre-desiliconizing the fly ash to an Al2O3 content of ≥40%, spot checking the particle size of the limestone and fly ash and the Al2O3 content in the fly ash, and checking whether the spot check is qualified; Step S2: 70.5 wt% of limestone, 28 wt% of fly ash, and 1.5 wt% of ZrO2 were wet-mixed in ethanol (ball milling speed 300 rpm, adding 0.3% polyacrylic acid dispersant) for 5 h; Step S3: adding 5 wt % polyethylene glycol to the wet-milled mixture, extruding at a working pressure of 8 MPa to obtain 3 mm particles, drying at 180° C. for 2 h, and inspecting the working pressure and particle size of the particles. The particles were found to be qualified. Step S4: Pre-calcining at a low temperature of 700°C at a heating rate of 5°C / min for 2 hours, and then final calcining at a high temperature of 850°C at a heating rate of 5°C / min for 4 hours to obtain a CO2 adsorbent having a Ca-Al framework and a Ca-Zr framework. The temperature, heating rate, and calcination time of the low-temperature pre-calcination, temperature, heating rate, and calcination time of the high-temperature final calcination, as well as the performance of the CO2 adsorbent were randomly inspected and qualified.

[0040] Comparative Example 1 Step S1, air flow pulverizing limestone to 1 μm, air flow pulverizing Al2O3 and ZrO2 to 0.5 μm, sieving the sieve material after pulverization, and spot-checking the particle sizes of limestone, Al2O3 and ZrO2, and checking whether the particle sizes are qualified; Step S2: 83.5 wt% of limestone, 15 wt% of Al2O3 and 1.5 wt% of ZrO2 were wet-milled in ethanol (ball milling speed 300 rpm, adding 0.3% sodium polyacrylate dispersant) for 5 h; Step S3: adding 5 wt % polyethylene glycol to the wet-milled mixture, extruding at a working pressure of 8 MPa to obtain 3 mm particles, drying at 180° C. for 2 h, and inspecting the working pressure and particle size of the particles. The particles were found to be qualified. Step S4: Pre-calcining at a low temperature of 700°C at a heating rate of 5°C / min for 2 hours, and then final calcining at a high temperature of 850°C at a heating rate of 5°C / min for 4 hours to obtain a CO2 adsorbent having a Ca-Al framework and a Ca-Zr framework. The temperature, heating rate, and calcination time of the low-temperature pre-calcination, temperature, heating rate, and calcination time of the high-temperature final calcination, as well as the performance of the CO2 adsorbent were randomly inspected and qualified.

[0041] Comparative Example 2 Step S1, air flow pulverizes limestone to 1 μm, air flow pulverizes fly ash to 1 μm, sieves the undersize material after pulverization, pre-desiliconizes the fly ash to an Al2O3 content of ≥40%, and randomly checks the particle size of limestone and fly ash and the Al2O3 content in the fly ash, and the random inspection is qualified; Step S2: 72 wt% of limestone and 28 wt% of fly ash were wet-milled with ethanol (ball milling speed of 300 rpm, with 0.3% sodium polyacrylate dispersant added) for 5 h; Step S3: adding 5 wt % polyethylene glycol to the wet-milled mixture, extruding at a working pressure of 8 MPa to obtain 3 mm particles, drying at 180° C. for 2 h, and inspecting the working pressure and particle size of the particles. The particles were found to be qualified. Step S4: Pre-calcining at a low temperature of 700°C at a heating rate of 5°C / min for 2 hours, and then final calcining at a high temperature of 850°C at a heating rate of 5°C / min for 4 hours to obtain a CO2 adsorbent having a Ca-Al framework. The temperature, heating rate, and calcination time of the low-temperature pre-calcination, temperature, heating rate, and calcination time of the high-temperature final calcination, as well as the performance of the CO2 adsorbent were randomly inspected and qualified.

[0042] Comparative Example 3 Step S1, air flow pulverizing limestone to 1 μm, air flow pulverizing fly ash and ZrO2 to 1 μm, sieving the undersize material after pulverization, pre-desiliconizing the fly ash to an Al2O3 content of ≥40%, spot checking the particle sizes of limestone, ZrO2 and fly ash and the Al2O3 content in the fly ash, and checking whether the particle sizes are qualified; Step S2: 70.5 wt% of limestone, 28 wt% of fly ash and 1.5 wt% of ZrO2 were wet-milled in ethanol (ball milling speed 300 rpm, adding 0.3% sodium polyacrylate dispersant) for 5 h; Step S3: adding 5 wt % polyethylene glycol to the wet-milled mixture, extruding at a working pressure of 8 MPa to obtain 3 mm particles, drying at 180° C. for 2 h, and inspecting the working pressure and particle size of the particles. The particles were found to be qualified. Step S4: calcining at a rate of 5°C / min to 850°C for 6 hours to obtain a CO2 adsorbent having a Ca-Al framework and a Ca-Zr framework. The calcination temperature, calcination heating rate, calcination time, and CO2 adsorbent performance were randomly inspected and the results were found to be qualified. The CO2 adsorbents prepared in Example 1 and Comparative Examples 1-3 are marked as Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3, respectively. Then, Example 1 and Comparative Examples 1-3 were tested, and the specific test results are analyzed as follows: Adsorption capacity test: The initial adsorption capacity of Example 1 is 0.56. After 30 cycles, the adsorption capacity attenuation rate is 21%, the specific surface area attenuation rate is 22%, and the anti-sintering ability is excellent. The initial adsorption capacity of Comparative Example 1 is 0.61. After 30 cycles, the adsorption capacity attenuation rate is 17%, the specific surface area attenuation rate is 21%, and the anti-sintering ability is excellent. Compared with Example 1, the CO2 adsorbent of Comparative Example 1 directly uses pure Al2O3. Although the adsorption capacity is slightly higher than that of Example 1, the unit price of pure Al2O3 in the comparative example is high. Example 1 significantly reduces the cost of raw materials while ensuring adsorption performance by resource utilization of industrial solid waste, saving about 500 yuan per ton, and has higher economic and sustainable development advantages. Therefore, from the perspective of large-scale production and economic benefits, Example 1 has greater application value for promotion. The initial adsorption capacity of Comparative Example 2 was 0.48, and after 30 cycles, the adsorption capacity decay rate was 40%, the specific surface area decay rate was 45%, and the sintering resistance was good. All test results were inferior to those of Example 1. This was because it contained only a Ca-Al single skeleton and no Ca-Zr skeleton to maintain the diffusion channel, and failed to optimize the crystal stability of the CO2 adsorbent. The initial adsorption capacity of Comparative Example 3 was 0.51, and after 30 cycles, the adsorption capacity decay rate was 33%, the specific surface area decay rate was 37%, and the sintering resistance was good. Compared with Example 1, Comparative Example 3 only differed in the calcination process. Comparative Example 3 did not adopt segmented calcination, and segmented calcination could better retain the pore structure of the CO2 adsorbent and effectively optimize the skeleton structure. The prepared CO2 adsorbent had better adsorption effect and cyclic stability. Therefore, the initial adsorption capacity, adsorption capacity decay rate after 30 cycles, specific surface area decay rate, and sintering resistance of Example 1 were all superior to those of Comparative Example 3.

[0043] In summary, as shown in Table 1, by allowing Al ions and Zr ions to coexist in a calcium matrix, the Ca-Al skeleton and the Ca-Zr skeleton dual-phase skeleton formed have a synergistic effect, that is, the Ca-Al skeleton provides high porosity, and the Ca-Zr skeleton maintains the diffusion channel, thereby effectively optimizing the pore structure and crystal stability of the CO2 adsorbent, increasing the initial adsorption capacity, significantly reducing the adsorption capacity attenuation rate, and enhancing the cycle life. At the same time, replacing chemical raw materials with industrial solid waste not only reduces the raw material procurement cost, but also reduces the solid waste disposal pressure. Example 1 uses industrial solid waste instead of Al2O3, and the initial adsorption capacity is slightly lower than that of Comparative Example 1, but the comprehensive cost of Example 1 is reduced by about RMB 500 / ton compared with Comparative Example 1. If the industrial solid waste Al2O3 used in Example 1 is The content is ≥40%, and there is no need for a desiliconization step, so the cost advantage is more obvious. In addition, since the CO2 adsorbent is used for CO2 capture, anti-sintering ability is also crucial. The introduction of ZrO2 and the two-stage calcination make Example 1 have a more stable skeleton structure and a more uniform pore structure. In comparison, Example 2 lacks the introduction of ZrO2, and Example 3 adopts a single-stage calcination method. The adsorption capacity attenuation rate is increased to varying degrees compared with Example 1. That is, the CO2 adsorbent of Example 1 has a higher ability to resist sintering (i.e., particle agglomeration, grain growth or porosity decrease) under the high temperature environment during CO2 capture than Examples 2 and 3, and can effectively maintain the microstructure and functional stability of the CO2 adsorbent, and further improve the cycle stability and service life.

[0044] Table 1 Comparison table of examples and comparative examples

[0045] The above embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and replacements made by technicians in this field on the basis of the present invention fall within the scope of protection required by the present invention.

Claims

1. A method for preparing a CO2 adsorbent based on industrial solid waste, characterized in that: The following steps are involved: pre-treating a calcium-based precursor and a support material precursor, and mixing and drying the treated calcium-based precursor and the support material precursor to obtain a mixture; calcining the mixture to obtain a CO2 adsorbent having a dual-phase framework; The support material precursor includes a mixed first metal oxide and a second metal oxide, and the first metal oxide is aluminum oxide contained in industrial solid waste.

2. The method for preparing a CO2 adsorbent based on industrial solid waste according to claim 1, wherein: The second metal oxide is ZrO2; The dual-phase skeleton is formed by combining a Ca-Al skeleton and a Ca-Zr skeleton.

3. The method for preparing a CO2 adsorbent based on industrial solid waste according to claim 1, wherein: The calcium-based precursor is any one of organic calcium and inorganic calcium or a combination of the two; The industrial solid waste is any one of fly ash, aluminum slag and steel slag.

4. The method for preparing a CO2 adsorbent based on industrial solid waste according to claim 1, wherein: The calcination includes low-temperature pre-calcination and high-temperature final calcination performed sequentially.

5. The method for preparing a CO2 adsorbent based on industrial solid waste according to claim 4, wherein: The temperature of the low-temperature pre-calcination is 650-750°C, the heating rate is 2-8°C / min, and the calcination time is 2-4h; The temperature of the high-temperature final calcination is 800-900° C., the heating rate is 2-8° C. / min, and the calcination time is 2-4 hours.

6. The method for preparing a CO2 adsorbent based on industrial solid waste according to claim 1, wherein: The pretreatment specifically comprises the following steps: Step S1, adjusting the calcium-based precursor and the support material precursor to set standards, wherein the set standards include a first set size of the calcium-based precursor, a second set size of the support material precursor, and a set impurity ratio of the support material precursor; Step S2: wet-mixing the calcium-based precursor under a set standard, the support material, and a solvent according to a set mixing ratio to obtain a mixture.

7. The method for preparing a CO2 adsorbent based on industrial solid waste according to claim 6, wherein: The specific steps of step S1 are: Grinding or crushing the calcium-based precursor to the first set size, grinding or crushing the support material precursor to the second set size; and / or The support material precursor is treated by acid washing, alkali washing or pre-desiliconization to reduce the impurity ratio.

8. The method for preparing a CO2 adsorbent based on industrial solid waste according to claim 1, wherein: The invention also includes the steps of forming and drying before the staged calcination: shaping and drying the mixture to obtain particles having a third set size, wherein the shaping method is any one of extrusion shaping, spray granulation and compression molding, and the shaping condition is a working pressure of 5-10 MPa; or The invention also includes the steps of forming and drying after the staged calcination: The CO2 adsorbent is molded and dried to obtain particles of a third set size, wherein the molding method is any one of extrusion molding, spray granulation and compression molding, and the molding condition is a working pressure of 5-10 MPa.

9. The method for preparing a CO2 adsorbent based on industrial solid waste according to claim 1, wherein: Also includes quality inspection steps: Set up quality inspection points and conduct random inspections on the materials and / or process operating conditions involved in each step.

10. An application of a CO2 adsorbent based on industrial solid waste, characterized in that: The CO2 adsorbent is prepared by the method according to any one of claims 1 to 9, and the CO2 adsorbent is used for carbon dioxide capture.

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