A method for filling abandoned mines with solid waste slurry and mineralizing and storing CO2

Abstract

The present invention belongs to the field of resource and environmental solid waste resource utilization building materials technology, and specifically relates to a method for filling abandoned mines with solid waste slurry and mineralizing and sealing CO2, comprising the following steps: S1, pouring and spraying solid waste-based sealing slurry on the bottom and wall of the abandoned mine, which forms a sealing layer after solidification; S2, injecting solid waste-based CO2 foam slurry into the abandoned mine, which forms a porous stone body filled with CO2 in the pores after solidification, which plays a supporting role for the abandoned mine; S3, injecting solid waste-based micro-expansion slurry on the top of the abandoned mine, which forms a closed protective shell after solidification to prevent CO2 from leaking from the abandoned mine. That is, CO2 can be stably sealed so that it is not discharged into the atmosphere, while solving the problem of solid waste accumulation polluting the environment and preventing the occurrence of problems such as broken surrounding rock collapse, mining area collapse and surrounding foundation subsidence in abandoned mines.

Description

Technical Field

[0001] The present invention belongs to the field of resource and environmental solid waste resource utilization and building material technology, and specifically relates to a method for filling abandoned mines with solid waste slurry and mineralizing and sealing CO2. Background Art

[0002] According to data released by the International Energy Agency (IEA), global CO2 emissions in 2022 will reach 338×10 8 t. Greenhouse gases such as CO2 have led to a series of serious environmental problems such as global warming and glacier melting. How to reduce CO2 emissions and reduce the impact of the greenhouse effect has become a difficult problem that the whole world needs to face and solve together. The accumulation of industrial solid wastes such as fly ash, desulfurization gypsum produced by thermal power plants and calcium carbide slag produced by chemical plants is large, causing serious pollution to the environment. In the process of coal mining, accidents such as collapse of broken surrounding rock, collapse of mining areas and subsidence of surrounding foundations are frequent, which need to be solved urgently. Grouting reinforcement materials are widely used in bridge and roadbed reinforcement, waterproofing and plugging, and prevention of collapse of broken and loose surrounding rock areas due to their advantages such as high strength, excellent fluidity and stable structure. Although current materials can effectively absorb carbon dioxide, such as concrete, since concrete is used in building structures, it does not have the enclosed space required for storage, making it impossible to store carbon dioxide gas.

[0003] "A Carbon Dioxide Storage Grouting Reinforcement Material and Its Construction Method" (Patent No.: CN109851309B) utilizes cement, microsilica fume or blast furnace slag powder or fly ash, water glass, alkylphenol polyoxyethylene ether, a water reducer, sodium lauryl sulfate, and water to form a slurry. The grouting reinforcement material is then rapidly injected into the surrounding rock to form a sealed surrounding rock area. Carbon dioxide is then injected into the divided surrounding rock area to seal the area. This patent utilizes the silica gel generated by the reaction of water glass and high-concentration carbon dioxide to reinforce the base layer, and later combines it with a high-alumina active cement material, which rapidly increases in strength, to reinforce the base layer. However, storing carbon dioxide underground presents safety issues such as gas leakage and secondary environmental pollution.

[0004] "Method for Coal-based Solid Waste Slurry Filling and Co-mineralization and Sequestration of CO2" (Patent No.: CN202310062924.3) This invention discloses a method for coal-based solid waste slurry filling and co-mineralization and sequestration of CO2. While using slurry filling technology to treat coal-based solid waste in mining areas, a goaf closed circle is constructed in the overburden fracture development area of the goaf. CO2 is pumped into the mine goaf along the same slurry conveying pipeline by pump pressure, and mineralization reaction occurs with the coal-based solid waste. This method is obviously a traditional way of pressurizing CO2 by pipeline and injecting it into the goaf, which has problems such as gas leakage. At the same time, the mineralization reaction only occurs on the upper and lower surfaces of the slurry, and the mineralization of CO2 cannot be achieved during the solidification process inside.

[0005] An invention patent application for a method of using industrial solid waste to seal carbon dioxide and fill large-area suspended roof goaf (patent number: CN202410372011.6) has been disclosed. The method involves transporting industrial solid waste and coal gangue to a crushing device for crushing and grinding, then adding cement and fly ash to the crushing device, and transporting the mixed solid waste mixture to a carbon fixation reaction device. A certain proportion of water is added to the carbon fixation reaction device and continuously stirred to form a solid waste mixed slurry. The carbon dioxide in the carbon dioxide collection device is transported to the carbon fixation reaction device and continuously stirred to allow the carbon dioxide and the solid waste mixed slurry to fully react to achieve carbon dioxide mineralization and form sealing material; drilling a sealing borehole and connecting it to a pumping device to pump the fully reacted sealing material to the suspended roof area device until the suspended roof area is filled.

[0006] The above method emphasizes the full reaction of CO2 with the solid waste slurry to form the sequestration material, meaning that CO2 is sequestered through a mineralization reaction during the mixing process. However, it simply pumps the sequestration material into the suspended ceiling device until it fills the suspended ceiling. This fails to stably seal the CO2 and prevent its release into the atmosphere, nor does it fundamentally address the environmental pollution caused by solid waste accumulation. Summary of the Invention

[0007] In response to the above technical problems, the present invention provides a method for filling abandoned mines with solid waste slurry and stably mineralizing and sealing CO2. This method can stably seal CO2 so that it is not discharged into the atmosphere, while solving the problem of solid waste accumulation polluting the environment and preventing abandoned mines from collapsing broken surrounding rocks, collapsing mining areas, and sinking surrounding foundations.

[0008] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0009] A method for filling abandoned mines with solid waste slurry and mineralizing and storing CO2, characterized by comprising the following steps:

[0010] S1. Pour and spray solid waste-based plugging slurry on the bottom and wall of the abandoned mine, and form a plugging layer after solidification;

[0011] S2. Inject solid waste-based CO2 foam slurry into the abandoned mine, which forms a porous stone body filled with CO2 in the pores after solidification, playing a supporting role for the abandoned mine;

[0012] S3. Inject solid waste-based micro-expansive slurry into the top of the abandoned mine, which forms a closed protective shell after solidification to prevent CO2 from leaking from the abandoned mine.

[0013] The solid waste-based plugging slurry in step S1 is composed of the following raw materials:

[0014] Solid powder: composed of two or more of steel slag powder, red mud, magnesium slag, fly ash, carbide slag, and desulfurization gypsum solid waste;

[0015] Liquid raw materials: composed of any one or more of water, water glass, and sodium hydroxide.

[0016] The solid waste-based plugging slurry is prepared by the following method: solid powder is put into a reactor and stirred evenly, and then liquid raw materials are added and stirred thoroughly to obtain the solid waste-based plugging slurry.

[0017] The solid waste-based CO2 foam slurry in step S2 is composed of the following raw materials:

[0018] Solid powder: composed of two or more of steel slag powder, red mud, magnesium slag, fly ash, carbide slag, and desulfurization gypsum solid waste;

[0019] Liquid raw materials: composed of any one or more of water, water glass, and sodium hydroxide.

[0020] The solid waste-based CO2 foam slurry is prepared by the following method: solid powder is put into a reactor and stirred evenly, then liquid raw materials are added and CO2 is introduced for sufficient stirring, and the solid waste-based CO2 foam slurry is obtained by pulping and carbonization.

[0021] The mass flow of the CO2 introduced is 1-2 L / min; the stirring time is 10-30 minutes, and the stirring speed is controlled at 400-1000 rpm.

[0022] The reaction cover in the reactor is porous to facilitate multi-site carbonization; a gas overflow collection device is provided in the reactor to recover the overflow gas; the reactor is made of steel or other pressure-resistant materials and can achieve pressurized ventilation to facilitate enhanced carbonation reaction and gas entrainment.

[0023] The solid waste-based slightly expansive slurry in step S3 is composed of the following raw materials: fly ash, carbide slag, coal gangue particles, an expansive agent and water.

[0024] The expansion agent is any one of quicklime, magnesium oxide, desulfurized gypsum, gypsum or expansive soil.

[0025] The solid waste-based micro-expanding slurry is obtained by the following preparation method: solid powder is put into a reactor and stirred evenly, and then water is added and stirred thoroughly to obtain the solid waste-based plugging slurry.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] Solid waste is used as the primary material for base sealing, followed by internal injection of mineralized slurry and top sealing. This method employs a comprehensive sealing method, combining a base, intermediate storage, and lid. By controlling the stirring speed (gas, liquid, and solid phases), the stirring process allows for the mineralization of carbon dioxide while trapping the carbon dioxide gas within the slurry. After grouting, the carbon dioxide is sealed within the solidified structure, forming dense pores. This prevents the carbon dioxide from escaping and allows for subsequent mineralization reactions.

[0028] Therefore, CO2 can be stably sealed so that it is not released into the atmosphere, while solving the problem of solid waste accumulation polluting the environment and preventing abandoned mines from experiencing problems such as broken surrounding rock collapse, mining area collapse, and surrounding foundation subsidence.

[0029] The solid waste-based plugging slurry of the present invention uses desulfurized gypsum as the main raw material, which is dried at a temperature of 105°C and forms calcium sulfate whiskers when it comes into contact with water, which helps to improve the system structure and increase its strength. The reactor cover involved in the preparation of solid waste-based CO2 foam grouting materials needs to be porous to facilitate the multi-site mineralization of CO2. Multi-site carbonization can make CO2 evenly distributed inside the slurry to form a stable slurry. Appropriate stirring conditions help to form stable CO2 microbubbles. Compared with the existing technology of injecting a large amount of CO2 into the ground for storage, it avoids secondary disasters caused by large-scale gas leakage and has higher safety. At the same time, the sealed CO2 microbubbles can continue to carry out subsequent reactions, achieving efficient fixation of CO2 and effective storage.

[0030] The CO2 introduced in the present invention can be CO2-containing waste gas emitted by factories, thermal power plants, industrial equipment, etc.; the main raw material of the grouting material is industrial solid waste, and the raw materials can be combined according to the local solid waste that is abundant, and adapted to local conditions. There is no need to transport the raw materials over long distances, which saves transportation costs and reduces raw material costs, reflecting ecological protection and comprehensive utilization of solid waste resources.

[0031] This invention incorporates carbon dioxide for pulping and mineralization, establishing a novel method for fluid injection of CO2 and solid waste particle slurry. This innovative multi-solid waste synergistic gelation method enhances in-situ carbon fixation, enabling simultaneous injection of CO2 and solid waste micropowders into backfill, while also improving the material's compressive strength. The present invention features a simple production method and stable performance, making it suitable for large-scale production. This invention utilizes waste for treatment and transforms waste into valuable resources, embodying the synergistic coupling of the social and environmental benefits of solid waste utilization and CO2 emission reduction with the economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a cross-sectional view of the abandoned mine after filling the abandoned mine with the present invention;

[0033] Figure 2 This is an SEM image of the solidified body of the solid waste-based plugging slurry of the present invention;

[0034] Figure 3 This is a diagram of a device for preparing a solid waste-based CO2 foam slurry according to the present invention;

[0035] Figure 4 It is a structural diagram of the reactor of the present invention;

[0036] Figure 5 It is a photo of the mineralized grouting stone body and a microscopic analysis diagram of the present invention;

[0037] Figure 6 This is a solid waste-based micro-expansion slurry consolidation body of the present invention and its horizontal and vertical sections;

[0038] Among them: 1 is solid waste-based sealing slurry, 2 is solid waste-based CO2 foam slurry, 3 is expanded solid waste slurry, 4 is a reactor, 5 is a gas overflow collection tank, 6 is a gas overflow collection pipe, 7 is a connecting pipe,

[0039] 8 is a mass flow meter, 9 is a carbon dioxide pressure reducing valve, and 10 is a carbon dioxide cylinder. DETAILED DESCRIPTION

[0040] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0041] The purpose of this embodiment is to provide a method for filling abandoned mines with solid waste slurry and mineralizing and storing CO2, which specifically includes the following three steps:

[0042] S1. Pour and spray solid waste-based sealing slurry on the bottom and wall of the abandoned mine, and form a sealing layer after solidification;

[0043] S2, injecting solid waste-based CO2 foam slurry into the abandoned mine, which solidifies to form a porous stone body with pores filled with CO2;

[0044] S3. Inject expandable solid waste slurry into the top of the abandoned mine, which forms a closed protective shell after solidification.

[0045] like Figure 1 As shown, through the above steps, the bottom and enclosure of the mine can be protected from leakage by the blocking layer; the abandoned mine can be supported by forming a porous stone body filled with CO2 in the pores; and the CO2 can be prevented from leaking from the abandoned mine by the closed protective shell.

[0046] That is, CO2 can be stably sealed so that it is not emitted into the atmosphere, while solving the problem of solid waste accumulation polluting the environment and preventing abandoned mines from experiencing problems such as broken surrounding rock collapse, mining area collapse, and surrounding foundation subsidence.

[0047] This embodiment provides a solid waste-based sealing slurry and a preparation method thereof based on Example 1.

[0048] 2.1. Solid waste-based sealing slurry

[0049] The solid waste-based plugging slurry is composed of the following raw materials: solid powder: a combination of two or more of solid wastes such as steel slag powder, red mud, magnesium slag, fly ash, carbide slag, desulfurization gypsum, etc. The liquid raw materials are composed of one or more of water, water glass, and sodium hydroxide.

[0050] Preferably, 50-70 parts of fly ash, 20-30 parts of carbide slag, 5-10 parts of desulfurized gypsum, 0-8 parts of water glass, 0-2 parts of sodium hydroxide, and 60-80 parts of water are mixed evenly.

[0051] 2.2 Preparation method

[0052] A method for preparing a solid waste-based plugging slurry comprises the following steps:

[0053] (1) Accurately weigh the following raw materials: 64 parts fly ash, 27 parts carbide slag, 9 parts desulfurized gypsum, 7 parts water glass, 1.5 parts sodium hydroxide, and 70 parts water. The Na2SiO3 modulus is 3.3 and the Baume degree is 40.

[0054] (2) According to the formula, the solid powder is put into the reactor and stirred evenly for 5 minutes, and then the liquid raw material is added and stirred thoroughly. The stirring speed is controlled at about 600 rpm and stirred for 20 minutes to obtain the solid waste-based plugging slurry.

[0055] The 28-day compressive strength of the solidified body after curing is 18.5 MPa and the density is 1.57 g / cm 3 , coagulation time 5.2h.

[0056] The present invention uses circulating fluidized bed fly ash, carbide slag, desulfurized gypsum, sodium hydroxide, water glass and water as raw materials. During the stirring process, volcanic ash and hydration reactions occur between the raw materials to generate gelling substances such as hydrated aluminosilicates. The desulfurized gypsum serves as whiskers to enhance the system structure.

[0057] Figure 2 This is the SEM image of the consolidated body. The calcium sulfate whiskers in the desulfurized gypsum are reinforced, and the rod-shaped substances are calcium sulfate whiskers, which can effectively inhibit the shrinkage of the system and create a dense structure. This is also one of the main reasons for the high compressive strength of the system.

[0058] This embodiment provides a solid waste-based CO2 foam slurry and a preparation method thereof based on Example 1.

[0059] 3.1. Solid waste-based CO2 foam slurry

[0060] Solid waste-based CO2 foam slurry is prepared from the following raw materials: solid powder is composed of two or more of solid wastes such as steel slag powder, red mud, magnesium slag, fly ash, carbide slag, desulfurization gypsum, etc.; liquid raw materials are composed of one or more of water, water glass, and sodium hydroxide.

[0061] Preferably, 50-70 parts of fly ash, 20-30 parts of carbide slag, 5-10 parts of desulfurization gypsum, 60-80 parts of water, and some CO2.

[0062] The CO2 introduced can be CO2-containing waste gas emitted by factories, thermal power plants, industrial equipment, etc.

[0063] 3.2 Preparation method

[0064] Preparation device of solid waste based CO2 foam slurry Figure 3 As shown, it includes a reactor, a mass flow meter, a carbon dioxide pressure reducing valve, and a carbon dioxide gas cylinder.

[0065] The preparation method of solid waste-based CO2 foam slurry comprises the following steps:

[0066] (1) Accurately weigh the following raw materials: 64 parts fly ash, 27 parts carbide slag, 9 parts desulfurized gypsum, 7 parts water glass, 1.5 parts sodium hydroxide, and 70 parts water. The Na2SiO3 modulus is 3.3 and the Baume degree is 40.

[0067] (2) Add the solid powder into the reactor according to the formula (such as Figure 4 As shown in FIG, the mixture was stirred evenly for 5 minutes, and then the liquid raw material was added and stirred thoroughly. The stirring speeds were controlled at 600 and 800 rpm, respectively. At the same time, CO2 was introduced into the reactor and stirred thoroughly. The mass flow rate of CO2 was 2 L / min.

[0068] (3) Stirring for 20 minutes can produce the solid waste-based CO2 foam slurry.

[0069] Figure 4 This is a reactor involved in the preparation process of the present invention, in which the reactor cover is designed with multiple openings to facilitate multi-site carbonization of CO2. Multi-site carbonization can make CO2 evenly distributed inside the slurry to form a stable slurry. The introduced CO2 reacts with calcium hydroxide to generate calcium carbonate, compacting the structural system, thereby improving the strength of the grouting reinforcement material, and at the same time, the CO2 is introduced through multiple pores; the reactor is made of steel or other pressure-resistant materials, which can achieve pressurized ventilation, thereby facilitating the enhancement of carbonation reaction and gas entrainment.

[0070] Specifically: Use a multi-channel pipe to guide CO2 to each hole, that is, each hole is inserted with a CO2 tube to achieve uniform ventilation. The tube mouth is extended to the bottom of the reactor, and the gas flow rate is controlled to maximize the contact time between the carbon dioxide gas and the slurry, ensuring the mineralization reaction and gas entrainment in the slurry, so that the carbon dioxide gas does not escape as much as possible.

[0071] It also includes a gas overflow collection device, which includes a gas overflow collection tank, a gas overflow collection pipe, and a connecting pipe; the reactor is connected to the gas overflow collection tank through the gas overflow collection pipe and the connecting pipe. The CO2 gas that enters the reactor but is not mineralized and is not entrained flows into the gas overflow collection tank through the gas overflow collection pipe and the connecting pipe for collection and reuse. At the same time, when the pressure in the gas overflow collection tank reaches a certain value, the CO2 gas therein will also return to the reactor through the gas overflow collection pipe and the connecting pipe for mineralization reaction. Specifically: corresponding valves are provided on the gas overflow collection pipe and the connecting pipe, and the valves are used to control the opening and closing of the gas overflow collection pipe and the connecting pipe.

[0072] Depend on Figure 4 It can be seen that the reactor cover of the device for preparing solid waste-based multi-site micro-foamed carbon fixation grouting reinforcement materials is distributed with multiple openings, which facilitate the introduction of CO2 at multiple locations, carry out multi-site carbonization, generate more nano-CaCO3, and enhance the system structure. During the carbonization process, carbon dioxide is converted from gas phase to liquid phase CO3 2- , and finally turns into solid phase CaCO3. In this multiphase transformation process, Gibbs free energy (ΔrG θ m , kJ / mol) < 0, the reaction can proceed spontaneously. The specific reaction process is shown in Equation 5-9.

[0073] CO2+H2O H2CO3(5)

[0074] H2CO3HCO3 - +H + (6)

[0075] HCO3 - CO3 2- +H + (7)

[0076] ΔrG θ m =ΔrH θ m -TΔS θ m (8)

[0077] ΔrG θm = -113.15+0.13(T+273.15) (9)

[0078] After curing at 600 rpm, the 28-day compressive strength of the solidified body is 18.9 MPa and the density is 1.58 g / cm 3 , coagulation time 4.8h.

[0079] After curing at 800 rpm, the 28-day compressive strength of the solidified body is 17.9 MPa and the density is 1.51 g / cm 3 , setting time 5.0h.

[0080] Figure 5 a and Figure 5 b shows that when placed in water, 800 rpm produces more bubbles than 600 rpm, and there are more uniform micropores at the interface after the solid body is cut, indicating that a large amount of CO2 can be blocked under high rotation speed conditions. Figure 5 c shows that the cross section of the stone body after solidification at 800 rpm presents uniform fine pores; Figure 5 Figure d shows the microscopic morphology of the stone after curing at 800 rpm. The specimen contains a large amount of nano-calcium carbonate, and the mineralized gel system exhibits an interlaced cloud-like and rod-like structure, resulting in a compact and dense internal structure. During the grouting process, CO₂ microbubbles trapped in the pores can continue to undergo subsequent mineralization reactions, achieving efficient CO₂ fixation, with an effective carbon fixation rate of up to 15%.

[0081] After 28 days of curing, the 28d strength of the grouting material increased to 25.2 MPa due to continuous mineralization.

[0082] This embodiment provides a solid waste-based micro-expanding slurry and a preparation method thereof based on Example 1.

[0083] 4.1. Solid waste-based micro-expansive slurry

[0084] The raw materials of solid waste-based micro-expanding slurry are composed of fly ash, carbide slag, coal gangue particles, expansion agent (quicklime, magnesium oxide, desulfurization gypsum, etc.), and water.

[0085] The preferred formula is 50-70 parts of fly ash, 20-30 parts of carbide slag, 0-10 parts of coal gangue particles, 5-10 parts of expansion agent (dried desulfurization gypsum), and 60-80 parts of water.

[0086] The expansion agent can be desulfurized gypsum, gypsum, expansive soil, etc. dried at 105°C.

[0087] The particle size of the coal gangue is less than 10 meshes.

[0088] 4.2 Preparation method

[0089] The preparation method of solid waste-based micro-expandable slurry comprises the following steps:

[0090] (1) Accurately weigh the following raw materials: 64 parts of fly ash, 27 parts of carbide slag, 10 parts of coal gangue particles (particle size less than 10 mesh), 9 parts of micro-expansion agent (desulfurized gypsum dried at 105°C) and water;

[0091] (2) According to the formula, the solid powder is put into the reactor and stirred evenly for 5 minutes, and then the liquid raw material is added and stirred thoroughly. The stirring speed is controlled at about 200 rpm and stirred for 20 minutes to obtain the solid waste-based micro-expandable slurry.

[0092] The compressive strength of the solidified body after curing is 17.9 MPa and the density is 1.58 g / cm 3 , coagulation time 5.1h.

[0093] Solid waste-based micro-expansion slurry consolidation body and its transverse and longitudinal sections Figure 6 As shown, the black areas represent gangue particles, while the white areas represent cementitious material. Cross-sectional and longitudinal sections reveal that the cementitious material tightly wraps around the gangue particles, demonstrating its excellent diffusivity and permeability, effectively consolidating the broken particles. Furthermore, the addition of a micro-expanding agent eliminates visible cracks within the stone, effectively sealing it and preventing CO2 from leaking from abandoned mines.

[0094] The above-mentioned "parts" all refer to parts by weight.

[0095] Only the preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the above embodiments.

Claims

1. A method for filling abandoned mines with solid waste slurry and mineralizing and storing CO2, characterized in that: The following steps are involved: S1. Pour and spray solid waste-based plugging slurry on the bottom and wall of the abandoned mine, and form a plugging layer after solidification; S2. Inject solid waste-based CO2 foam slurry into the abandoned mine, which forms a porous stone body filled with CO2 in the pores after solidification, playing a supporting role for the abandoned mine; S3. Inject solid waste-based micro-expansive slurry into the top of the abandoned mine, which forms a closed protective shell after solidification to prevent CO2 from leaking out of the abandoned mine; The solid waste-based CO2 foam slurry in step S2 is composed of the following raw materials: Solid powder: composed of two or more of steel slag powder, red mud, magnesium slag, fly ash, carbide slag, desulfurization gypsum solid waste; liquid Raw materials: any one or more of water, water glass, and sodium hydroxide; The solid waste-based CO2 foam slurry is prepared by the following method: solid powder is put into a reactor and stirred evenly, and then a liquid raw material is added and CO2 is introduced and stirred thoroughly, and slurry carbonization is performed to obtain the solid waste-based CO2 foam slurry; the mass flow rate of the introduced CO2 is 1-2 L / min; the stirring time is 10-30 minutes, and the stirring speed is controlled to be 400-1000 rpm; The reactor cover is porous to facilitate multi-site carbonization; a gas overflow collection device is provided in the reactor to recover the overflow gas; the reactor is made of steel or other pressure-resistant materials, which can achieve pressurized ventilation to facilitate enhanced carbonation reaction and gas entrainment; The solid waste-based slightly expansive slurry in step S3 is composed of the following raw materials: fly ash, carbide slag, coal gangue particles, an expansive agent and water; the expansive agent is any one of quicklime, magnesium oxide, gypsum or expansive soil.

2. The method for filling abandoned mines with solid waste slurry and mineralizing and storing CO2 according to claim 1, characterized in that: The solid waste-based plugging slurry in step S1 is composed of the following raw materials: Solid powder: composed of two or more of steel slag powder, red mud, magnesium slag, fly ash, carbide slag, and desulfurization gypsum solid waste; Liquid raw materials: composed of any one or more of water, water glass, and sodium hydroxide.

3. The method for filling abandoned mines with solid waste slurry and mineralizing and storing CO2 according to claim 2, characterized in that: The solid waste-based plugging slurry is prepared by the following method: solid powder is put into a reactor and stirred evenly, and then liquid raw materials are added and stirred thoroughly to obtain the solid waste-based plugging slurry.

4. The method for filling abandoned mines with solid waste slurry and mineralizing and storing CO2 according to claim 1, characterized in that: The solid waste-based micro-expanding slurry is obtained by the following preparation method: solid powder is put into a reactor and stirred evenly, and then water is added and stirred thoroughly to obtain the solid waste-based plugging slurry.

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