A system, method and product for co-mineralizing carbon dioxide with steel slag to prepare building materials

Abstract

The present invention discloses a system, method and product for preparing building materials by synergistically mineralizing carbon dioxide with steel slag, belonging to the technical fields of application of solid waste and environmental protection. The system includes a steel slag pretreatment unit, a premixing unit and a constant temperature mineralization unit. The preparation method is as follows: First, the steel slag is pretreated by a three-stage crushing method to obtain steel slag powder, then the steel slag powder, gypsum and cement are fed into a backmixing type mixing bin for mixing to obtain a mixture; finally, the mixture, full tailings and water are fed into a constant temperature mineralization reactor and reacted under supercritical CO2 conditions to obtain the building materials. The present invention uses the supercritical CO2 mineralization process to prepare building materials from steel slag and full tailings, effectively solving the problem of waste pollution. Moreover, the prepared building materials also have high mechanical properties and can be applied in different building fields, which is a promising technology in the future building materials field.

Description

Technical Field

[0001] The present invention belongs to the field of solid waste application and environmental protection technology, and specifically relates to a system, method and product for preparing building materials by cooperating with steel slag to mineralize carbon dioxide. Background Art

[0002] Waste of building materials has always been one of the environmental problems that need to be solved urgently. The waste gas and products generated by the conventional production process often cause environmental pollution and pose a huge threat to humans and the ecological environment. Therefore, the production method of green and environmentally friendly building materials is an innovation that the industry urgently needs today.

[0003] In the prior art, people often use certain technical means to prepare waste into building materials. For example, steel slag mineralization technology, by reacting steel slag with other raw materials to produce a mineralization reaction, the steel slag is converted into a new type of building material. However, the method of preparing building materials using steel slag mineralization technology often requires a lot of energy and also produces a lot of waste gases such as carbon dioxide. Therefore, the field is in urgent need of a new method for preparing building materials by co-mineralizing CO2 with steel slag.

[0004] Patent CN115466072A studies a CO2-mineralized building material and preparation method for solid waste from the steel industry, and proposes a method of fixing carbon dioxide using active calcium components in solid waste, limiting the mass ratio of mineralizable solid waste to silicon-aluminum solid waste, so that it has a higher mineralization activity, so that the solid waste products can achieve a certain compressive strength while increasing the carbon fixation rate, and no additional heating is required during the process, saving energy. Patent CN114538876A studies a method of using industrial / mining solid waste to mineralize CO2 to prepare mine cementing filling materials, and proposes that industrial / mining solid waste and ammonium nitrate are activated by molten salt in a reactor, and then treated by water immersion. The obtained water immersion liquid reacts with carbon dioxide to obtain mineralized slag, organically integrating CO2 mineralization storage with geological storage technology, and realizing the upgrading and transformation of metal mining. The above two patents both use steel slag to prepare building materials, and treat the steel slag by mineralization and other methods. However, there are still some problems, such as the need to use a large amount of acid or alkali in the pretreatment and mineralization process, the possible secondary pollution and consumption of a large amount of chemical raw materials in the production process, and the low efficiency of solid waste fixation of CO2. These problems need to be further improved.

[0005] In summary, it is very necessary to study a system and method for the continuous, efficient and high-efficiency mineralization of steel slag and CO2 to prepare building materials. Summary of the invention

[0006] In order to solve the above problems in the prior art, the present invention provides a system, method and product for preparing building materials by using steel slag to coordinately mineralize carbon dioxide.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] One of the technical solutions of the present invention: Provide a system for co-mineralizing carbon dioxide with steel slag to prepare building materials, the system sequentially includes a steel slag pretreatment unit, a premixing unit, and a constant temperature mineralization unit;

[0009] The inlet of the premixing unit is communicated with the outlet of the steel slag pretreatment unit, and the outlet of the premixing unit is communicated with the inlet of the constant temperature mineralization unit;

[0010] The steel slag pretreatment unit sequentially includes a jaw crusher, a cone crusher, a roll press crusher, a magnetic separator, and a tube mill;

[0011] The premixing unit includes a backmixing type mixing bin;

[0012] The constant temperature mineralization unit includes a constant temperature mineralization reactor.

[0013] Beneficial effects: By pretreating the steel slag, the present invention ensures that it can be fully mixed with other materials, meeting the requirements of mineralization for raw materials. Premixing the materials before mineralization can improve the uniformity of the materials, providing a guarantee for obtaining products of better quality. Then, through the mineralization reaction, the mineralization of waste is realized, and finally building materials superior to traditional products are obtained, achieving the resource recovery and utilization of waste.

[0014] The second technical solution of the present invention: The present invention provides a method for co-mineralizing carbon dioxide with steel slag to prepare building materials, including the following steps:

[0015] (1) Feed the steel slag into the steel slag pretreatment unit for classification and crushing, and then obtain steel slag powder after magnetic separation by the magnetic separator and grinding by the tube mill;

[0016] (2) Feed the steel slag powder, gypsum, and cement into the backmixing type mixing bin for mixing to obtain a mixture;

[0017] (3) Feed the mixture, total tailings, and water into the constant temperature mineralization reactor, and react under supercritical CO2 conditions to obtain the building materials.

[0018] Beneficial effects: By magnetic separation with the magnetic separator, the present invention removes particle steel and slag particles, further reducing the influence of impurities. Moreover, during the entire steel slag pretreatment process in the present invention, the powder is in a closed conveying system, reducing dust escape and environmental pollution.

[0019] Further, in step (1), the grinding is to 100 - 800 meshes, preferably 500 - 600 meshes.

[0020] Beneficial effects: The smaller the particle size of the powder, the larger its surface area, the more conducive it is to fully mix with other materials and CO2, the better the mineralization effect, and the more stable the quality of the obtained product. However, if the particle size is too small, the more difficult the powder is to process, the higher the equipment requirements are. Therefore, the present invention grinds the steel slag to 100-800 mesh.

[0021] Furthermore, the graded crushing process in step (1) comprises the following steps: firstly, the jaw crusher is used for primary crushing, and the steel slag with a particle size less than 100 mm is crushed by the cone crusher for secondary crushing, and then the steel slag with a particle size less than 10 mm is further crushed by the roller crusher for tertiary crushing, and the steel slag with a particle size less than 3 mm is obtained after screening.

[0022] Beneficial effects: In the present invention, three-stage different types of crushing equipment are used to pre-treat the steel slag, which can effectively improve the crushing efficiency, reduce the crushing energy consumption, and at the same time meet the requirement of more uniform material after crushing.

[0023] Furthermore, in step (2), the mass ratio of the steel slag powder, gypsum and cement is (9-10):3:(3-4); the stirring speed during the mixing is 150-300 rpm, the time is 20 min, and the temperature is 20-35° C. In the present invention, when the mixed material enters the back-mixing mixing bin, the stirring device in the mixing bin is turned on to ensure that the steel slag powder, gypsum and cement are fully mixed.

[0024] Furthermore, in step (3), the mass ratio of the mixture, the whole tailings and the water is (7-8): (1-2): 1; the reaction temperature is 35-75°C, the reaction time is 20-240min, the pressure is 8-20MPa, and the CO2 concentration is 95-99%.

[0025] Beneficial effects: After the present invention premixes materials of different proportions through a back-mixing mixing bin, the materials become more uniform, and the contact area between the reactants is increased, thereby improving the efficiency and speed of the mineralization reaction. After premixing, the reaction state can be entered more quickly, thereby reducing the mineralization reaction time of CO2, improving the reaction effect and product production efficiency. The improvement in reaction efficiency optimizes the reaction temperature and reaction time, thereby reducing energy consumption in the mineralization process. The mineralization process further promotes the interaction and reaction rate between the reactants and improves the mineralization efficiency by strictly controlling the reaction conditions. Moreover, controlling the mineralization reaction conditions within the above range can further improve the product quality and purity of the mineralization reaction, and effectively improve the commercial value and use effect of the product.

[0026] Further, the preparation process of the supercritical CO2 in step (3) is specifically as follows: A CO2 circulation system is adopted. The CO2 gas is compressed by a compressor. After obtaining a pressurized gas pressurized to 3 - 6 MPa, it is sent into a CO2 storage tank. The pressurized CO2 gas is further pressurized to 4 - 7 MPa by a pressure pump to obtain liquid CO2, which is then sent into a liquid CO2 tank. The liquid CO2 is further pressurized to above 7.39 MPa by a pressure pump. The liquid CO2 is heated and raised in temperature by a thermostat. When the temperature rises to 31.3 - 60 °C, supercritical CO2 gas can be obtained, and then it is sent into a constant-temperature mineralization reactor to participate in the reaction.

[0027] The third aspect of the technical solution of the present invention: The present invention also provides a building material prepared by using the method for preparing a building material by synergistic mineralization of carbon dioxide with steel slag as described above.

[0028] Further, the building material comprises the following raw materials in parts by weight: 40 - 70 parts of steel slag, 10 - 20 parts of gypsum, 10 - 20 parts of cement, 5 - 10 parts of total tailings, and 10 - 20 parts of water.

[0029] Furthermore, the specific surface areas of the gypsum and the cement are 300 - 500 m 2 / kg.

[0030] Further, the raw materials further comprise an oxidant; the oxidant includes any one of oxygen, ozone, or hydrogen peroxide; the oxidant is mixed into the supercritical CO2 in a gaseous state.

[0031] Among them, when the oxidant is oxygen, the addition amount is 0.5 - 2.0% (by volume of CO2);

[0032] When the oxidant is ozone, the addition amount is 0.01 - 0.05% (by volume of CO2);

[0033] When the oxidant is hydrogen peroxide, the addition amount is 0.2 - 1.0% (by volume of CO2).

[0034] Beneficial effects: The present invention reduces carbon emissions through the process of solidifying CO2, thereby achieving the goal of reducing greenhouse gas emissions. By using supercritical CO2 to react with steel slag, the reaction rate and conversion rate are increased, and the hardness and chemical stability of building materials are improved. During the preparation process, the mechanical properties and functions of building materials are further improved by adding oxidants. In addition, through the recycling of supercritical CO2, the loss of CO2 can be reduced, thereby saving the consumption of CO2 and improving the utilization efficiency of CO2; the cost of CO2 mineralization is also reduced, thus promoting the practical application and popularization of CO2 emission reduction technologies. Recycling CO2 can also improve the efficiency and reaction rate of CO2 mineralization, thereby shortening the reaction time, reducing energy consumption and mineralization costs. The recycling of CO2 can reduce CO2 emissions, reduce the impact on the environment, and enhance the environmental benefits and sustainability of CO2 emission reduction technologies.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] The supercritical CO2 gas adopted by the present invention to replace the traditional atmospheric pressure or pressurized CO2 for mineralizing steel slag to prepare building materials has the following advantages. First, the solubility of supercritical CO2 in cations is high, which can better penetrate into the solid-liquid phase, with a faster reaction speed, greatly shortening the reaction time, higher mineralization efficiency, and reducing the treatment time and cost; second, using supercritical CO2 can operate at high temperature and high pressure, thus providing a wider range of reaction conditions for the mineralization process; third, supercritical CO2 can achieve a higher carbonization depth and a more complete reaction, thereby producing a stronger and more durable final product; supercritical CO2 will reduce the energy required for the mineralization process, thereby reducing costs and increasing efficiency; fourth, the supercritical CO2 process can also adapt to different types of industrial wastes, including fly ash, bottom ash, and blast furnace slag mineralization requirements; fifth, compared with the traditional cement production method, using supercritical CO2 requires less water, thereby reducing water consumption and related environmental impacts; sixth, the supercritical CO2 process can improve the reactivity of industrial by-products, thereby using less materials in the production process.

[0037] The present invention utilizes a supercritical CO2 mineralization process to prepare building materials, which can utilize industrial solid waste such as steel slag and all-tailings, convert them into resource-based products with high safety factors, achieve sustainable utilization of waste steel slag resources, reduce their environmental pollution, and effectively solve the problem of treating these waste materials. By using resources such as CO2 and solid waste to carry out mineralization reactions to prepare building materials, not only can the emissions of industrial waste and environmental pollution be reduced, but also the comprehensive utilization of these waste materials can be realized, thereby reducing the pressure on the ecological environment. This method not only solves the problem of CO2 emissions, but also manufactures high-quality building materials through supercritical CO2 mineralization reactions. The building materials have advantages such as high efficiency, energy conservation, and environmental protection. In addition, during the process of synergistic mineralization to prepare building materials in the present invention, waste steel slag can be synergistically mineralized, thereby realizing waste conversion and utilization, demonstrating the concept of energy conservation and environmental protection. Moreover, the mechanical properties of the building materials prepared by the present invention have a certain degree of stability and controllability within a certain range, have relatively high strength and hardness, and can meet the technical requirements of the building field for material strength and other aspects. The building materials prepared by supercritical CO2 mineralization reactions have the characteristics of fast hardening speed, can reduce the production process flow to a certain extent, and improve production efficiency. Using the supercritical CO2 mineralization process to manufacture building materials greatly improves the strength, density, and stability of the products. The manufactured building materials have stable product quality, are not affected by seasonal changes, and the products are more durable and safe. Their strength, durability, waterproofness, heat insulation, etc. are better, and they can be applied in different building fields, such as building structures, waterproofing, heat insulation and other fields. The materials have multi-functional applications and can also be suitable for high-temperature environments. Supercritical CO2 mineralization reactions can achieve efficient production of materials, are conducive to improving the yield and reducing the manufacturing cost, and are a promising technology in the future building materials field. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The drawings forming a part of this application are used to provide a further understanding of this application. The schematic embodiments of this application and their descriptions are used to explain this application and do not constitute an improper limitation of this application. In the drawings:

[0039] Figure 1 It is a schematic diagram of a system for synergistic mineralization of carbon dioxide with steel slag to prepare building materials in Embodiment 1 of the present invention;

[0040] Reference numerals: S1 - steel slag pretreatment unit, S2 - premixing unit, S3 - constant temperature mineralization unit;

[0041] Figure 2 It is a schematic process flow diagram in Embodiment 2 of the present invention;

[0042] Figure 3 It is a schematic diagram of a supercritical CO2 circulation system in Embodiment 2 of the present invention;

[0043] Figure 4 Explanation of the schematic diagram of the supercritical CO2 circulation system in Embodiment 2 of the present invention;

[0044] Reference numerals: 1 - constant temperature mineralization reactor, 2 - compressor, 3 - CO2 storage tank, 4 - pressurizing pump, 5 - liquid CO2 storage tank, 6 - pressurizing pump, 7 - thermostat. Detailed implementation manners

[0045] Now, various exemplary implementation manners of the present invention will be described in detail. This detailed description should not be regarded as a limitation of the present invention, but should be understood as a more detailed description of certain aspects, characteristics, and implementation schemes of the present invention.

[0046] It should be understood that the terms used in the present invention are only for describing specific implementation manners and are not used to limit the present invention. Additionally, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded from the range.

[0047] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. Although the present invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein can also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In case of conflict with any incorporated document, the content of this specification shall prevail.

[0048] Without departing from the scope or spirit of the present invention, various improvements and changes can be made to the specific implementation manners of the present invention specification, which are obvious to those skilled in the art. Other implementation manners obtained from the present invention specification are obvious to those skilled in the art. The present invention specification and embodiments are only exemplary.

[0049] Regarding the terms "comprising", "including", "having", "containing", etc. used herein, they are all open-ended terms, meaning including but not limited to.

[0050] Embodiment 1

[0051] A system for synergistically mineralizing carbon dioxide with steel slag to prepare building materials, the schematic diagram is as Figure 1As shown in the figure, it includes a steel slag pretreatment unit S1, a premixing unit S2, and a constant-temperature mineralization unit S3; the inlet of the premixing unit S2 is connected to the outlet of the steel slag pretreatment unit S1, and the outlet of the premixing unit S2 is connected to the inlet of the constant-temperature mineralization unit S3; among them, the steel slag pretreatment unit includes a jaw crusher, a cone crusher, a roller press crusher, a magnetic separator, and a tube mill, the premixing unit includes a back-mixing type mixing bin, and the constant-temperature mineralization unit includes a constant-temperature mineralization reactor.

[0052] Example 2

[0053] A method for preparing building materials by synergistically mineralizing carbon dioxide with steel slag, using the system of Example 1 above, the process flow chart is as Figure 2 shown, and includes the following steps:

[0054] (1) First, 10t of steel slag is subjected to primary crushing using a jaw crusher, the steel slag with a particle size less than 100mm is then subjected to secondary crushing using a cone crusher, and then the steel slag with a particle size less than 10mm is continuously subjected to tertiary crushing using a roller press crusher. After screening, steel slag with a particle size of about 2mm is obtained, and then it is sent into a magnetic separator for magnetic separation treatment. After screening out particle steel and slag particles, the remaining material is sent into a tube mill for further grinding to 500 - 600 mesh to obtain steel slag powder;

[0055] (2) The steel slag powder obtained in step (1), gypsum, and cement are placed in a back-mixing type mixing bin and mixed at a mass ratio of 10∶3∶3, the stirring speed is 300rpm, the stirring time is 20min, and the temperature is 35°C to obtain a mixture. Among them, the specific surface area of gypsum and cement is 300 - 500m 2 / kg;

[0056] (3) The mixture obtained in step (2), total tailings, and water are sent into a constant-temperature mineralization reactor for reaction at a mass ratio of 8∶1∶1. 0.02% ozone is introduced into the reactor, and CO2 with a concentration of 98% is pressurized to 16MPa by a pressure pump and heated to 45°C to obtain supercritical CO2, which is sent into the constant-temperature mineralization reactor. The reaction temperature is 45°C, and the reaction time is 100min. Among them, the schematic diagram of preparing supercritical CO2 using a supercritical CO2 circulation system is as Figure 3 shown, and the description of this schematic diagram is as Figure 4 shown, that is, building materials are obtained, and this building material can be directly used as building concrete.

[0057] Example 3

[0058] A method for preparing building materials by synergistically mineralizing carbon dioxide with steel slag, using the system of Example 1 above, includes the following steps:

[0059] (1) First, the 15t steel slag is subjected to primary crushing using a jaw crusher. The steel slag with a particle size less than 100mm is then subjected to secondary crushing using a cone crusher. Subsequently, the steel slag with a particle size less than 10mm is further subjected to tertiary crushing using a roller press crusher. After screening, steel slag with a particle size of approximately 2mm is obtained, which is then fed into a magnetic separator for magnetic separation treatment. After screening out the particle steel and slag particles, the remaining material is fed into a tube mill for further grinding to 300 - 500 mesh to obtain steel slag powder;

[0060] (2) The steel slag powder obtained in step (1), gypsum, and cement are mixed in a back-mixing type mixing bin at a mass ratio of 9∶3∶4. The stirring speed is 200rpm, the stirring time is 20min, and the temperature is 20°C to obtain a mixture. Among them, the specific surface area of gypsum and cement is 300 - 500m 2 / kg;

[0061] (3) The mixture obtained in step (2), total tailings, and water are fed into a constant-temperature mineralization reactor for reaction at a mass ratio of 7∶2∶1. 1.0% oxygen is introduced into the reactor, and CO2 with a concentration of 95% is pressurized to 8MPa by a pressure pump and heated to 38°C to obtain supercritical CO2, which is then fed into the constant-temperature mineralization reactor. The reaction temperature is 38°C, and the reaction time is 220min to obtain building materials.

[0062] Example 4

[0063] A method for preparing building materials by synergistic mineralization of carbon dioxide with steel slag, using the system of Example 1 above, includes the following steps:

[0064] (1) First, the 12t steel slag is subjected to primary crushing using a jaw crusher. The steel slag with a particle size less than 100mm is then subjected to secondary crushing using a cone crusher. Subsequently, the steel slag with a particle size less than 10mm is further subjected to tertiary crushing using a roller press crusher. After screening, steel slag with a particle size of approximately 2mm is obtained, which is then fed into a magnetic separator for magnetic separation treatment. After screening out the particle steel and slag particles, the remaining material is fed into a tube mill for further grinding to 350 - 450 mesh to obtain steel slag powder;

[0065] (2) The steel slag powder obtained in step (1), gypsum, and cement are mixed in a back-mixing type mixing bin at a mass ratio of 10∶3∶3. The stirring speed is 200rpm, the stirring time is 20min, and the temperature is 30°C to obtain a mixture. Among them, the specific surface area of gypsum and cement is about 450m 2 / kg;

[0066] (3) Feed the mixture obtained in step (2), total tailings and water into a constant-temperature mineralization reactor at a mass ratio of 7:2:1 for reaction. Inject 0.5% hydrogen peroxide into the reactor, pressurize CO2 with a concentration of 97% to 12 MPa through a pressure pump, heat it to 55 °C to obtain supercritical CO2, and feed it into the constant-temperature mineralization reactor. The reaction temperature is 70 °C and the reaction time is 30 min, thus obtaining the building material.

[0067] Comparative Example

[0068] A method for preparing building materials by co-mineralizing carbon dioxide with steel slag, which is only different from Example 2 in that the CO2 concentration in step (3) is 90%;

[0069] The remaining steps are the same as those in Example 2.

[0070] Effect verification:

[0071] Prepare the building materials prepared in Examples 2-4 and the comparative example into concrete, and measure their compressive strength, density and waterproofness. Among them, the determination of compressive strength is based on "Standard Test Method for Compressive Strength of Concrete" (GB / T 50081-2002), the determination of waterproofness is based on "Standard for Classification of Building Waterproof Grades", and the determination of density is based on "Code for Acceptance of Construction Quality of Building Engineering" (GB / T 50080-2016). The results are shown in Table 1, where the compressive strength of local conventional concrete is 40-50 MPa and the density is 2.20-2.45 g / cm 3 .

[0072] Table 1

[0073]

[0074] As can be seen from Table 1, the building materials prepared by the method of the present invention have obvious advantages in compressive strength compared with traditional building materials, and products with different compressive strengths can be obtained by changing the operating conditions, but there is no obvious impact on waterproofness, and their waterproofness can all reach Grade II.

[0075] The above is only the preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A method for preparing building materials by co - mineralizing carbon dioxide with steel slag, characterized in that, Using a system for preparing building materials by co - mineralizing carbon dioxide with steel slag to prepare building materials, the system sequentially includes a steel slag pretreatment unit, a premixing unit, a constant - temperature mineralization unit, and a CO2 recycling system; The inlet of the premixing unit is communicated with the outlet of the steel slag pretreatment unit, and the outlet of the premixing unit is communicated with the inlet of the constant - temperature mineralization unit; The steel slag pretreatment unit sequentially includes a jaw crusher, a cone crusher, a roll press crusher, a magnetic separator, and a tube mill; The premixing unit includes a back - mixing type mixing bin; The constant - temperature mineralization unit includes a constant - temperature mineralization reactor; The CO2 recycling system is cyclically communicated with the constant - temperature mineralization unit; The method for preparing building materials by co - mineralizing carbon dioxide with steel slag includes the following steps: (1) Feed the steel slag into the steel slag pretreatment unit for classification and crushing, and then after magnetic separation by the magnetic separator and grinding by the tube mill, obtain steel slag powder; (2) Feed the steel slag powder, gypsum, and cement into the back - mixing type mixing bin for mixing to obtain a mixture; (3) Feed the mixture, full tailings, and water into the constant - temperature mineralization reactor, and react under supercritical CO2 conditions to obtain the building materials; The preparation process of the supercritical CO2 is specifically as follows: Adopt a CO2 recycling system. The CO2 gas is compressed by a compressor to obtain a pressurized gas pressurized to 3 - 6 MPa and then fed into a CO2 storage tank. The pressurized CO2 gas is further pressurized to 4 - 7 MPa by a pressure pump to obtain liquid CO2, which is then fed into a liquid CO2 tank. The liquid CO2 is further pressurized to above 7.39 MPa by a pressure pump. The liquid CO2 is heated and raised in temperature by a thermostat, and when the temperature rises to 31.3 - 60 °C, supercritical CO2 gas can be obtained, and then it is fed into the constant - temperature mineralization reactor to participate in the reaction.

2. The method for preparing building materials by co-mineralizing carbon dioxide with steel slag according to claim 1, wherein In step (1), the grinding is to 100 - 800 meshes; The classification and crushing treatment includes the following steps: First, perform primary crushing with the jaw crusher on steel slag with a particle size less than 100 mm, then perform secondary crushing on the steel slag with a particle size less than 10 mm with the cone crusher, and then continue to perform tertiary crushing on the steel slag with a particle size less than 3 mm with the roll press crusher. After screening, steel slag with a particle size less than 3 mm is obtained.

3. The method for preparing building materials by co - mineralizing carbon dioxide with steel slag according to claim 1, characterized in that, In step (2), the mass ratio of the steel slag powder, gypsum, and cement is (9 - 10)∶3∶(3 - 4); The stirring speed of the mixing is 150 - 300 rpm, the time is 20 min, and the temperature is 20 - 35 °C.

4. The method for preparing building materials by co - mineralizing carbon dioxide with steel slag according to claim 1, wherein, In step (3), the mass ratio of the mixture, full tailings, and water is (7 - 8)∶(1 - 2)∶1; The temperature of the reaction is 35 - 75 °C, the time is 20 - 240 min, the pressure is 8 - 20 MPa, and the CO2 concentration is 95 - 99%.

5. A building material prepared by the method for preparing building materials by co - mineralizing carbon dioxide with steel slag according to any one of claims 1 - 4.

6. The building material according to claim 5, characterized in that, The building material includes the following raw materials in parts by weight: 40 - 70 parts of steel slag, 10 - 20 parts of gypsum, 10 - 20 parts of cement, 5 - 10 parts of full tailings, and 10 - 20 parts of water.

7. The building material according to claim 6, wherein The raw materials further include an oxidizing agent; The oxidizing agent includes any one of oxygen, ozone or hydrogen peroxide; Wherein, when the oxidizing agent is oxygen, the addition amount is 0.5-2.0%; When the oxidizing agent is ozone, the addition amount is 0.01-0.05%; When the oxidizing agent is hydrogen peroxide, the addition amount is 0.2-1.0%.

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