Solid waste-based cementing material based on carbon mineralized magnesium slag as well as preparation method and application of solid waste-based cementing material

Abstract

The invention relates to the technical field of resource utilization of building materials and solid wastes, in particular to a solid waste-based cementing material based on carbon mineralized magnesium slag as well as a preparation method and application of the solid waste-based cementing material. The solid waste-based cementing material based on the carbon mineralized magnesium slag, provided by the invention, is prepared from the following raw materials in parts by weight: 33 to 60 parts of slag, 15 to 35 parts of steel slag, 8 to 20 parts of gypsum and 10 to 25 parts of the carbon mineralized magnesium slag. The solid waste-based cementing material based on the carbon mineralized magnesium slag can effectively solve the problems that a traditional solid waste-based cementing material is long in setting and hardening time and low in early strength, does not need to be added with extra cement or alkaline excitant or coagulant, belongs to an all-solid-waste system, has the advantages of being low in cost and high in strength, has the carbon sequestration effect, and is suitable for large-scale popularization and application. The method is suitable for different working conditions and application scene requirements.

Description

Technical Field

[0001] This invention relates to the field of building materials and solid waste resource utilization technology, and in particular to a solid waste-based cementitious material based on carbonized magnesium slag, its preparation method and application. Background Technology

[0002] With the rapid development of China's industrialization, the generation of industrial solid wastes such as blast furnace slag, steel slag, fly ash, and industrial by-product gypsum has continued to rise. However, the overall utilization rate of these industrial solid wastes is currently low, and their large-scale stockpiling not only occupies valuable land resources but also poses a potential threat to the surrounding ecological environment. Therefore, promoting the reduction, harmless treatment, and resource utilization of industrial solid waste has become a critical issue that urgently needs to be addressed. Using these solid wastes to prepare cementitious materials is an important way to achieve their large-scale utilization and a key measure for the building materials industry to achieve low-carbon transformation and development.

[0003] Solid waste-based cementitious materials refer to low-carbon cementitious materials formed by using one or more industrial solid wastes as main raw materials and achieving hydration hardening characteristics through the synergistic activation effect between components. Compared with traditional silicate cement, its production process can significantly reduce carbon emissions. However, existing solid waste-based cementitious materials generally have some inherent defects, the most prominent of which are excessively long setting times and slow early strength development. This performance shortcoming severely limits its promotion in application scenarios requiring rapid demolding, early load-bearing capacity, or winter construction, putting it at a disadvantage in competition with traditional cement.

[0004] To address the aforementioned technical problems, several solutions have been proposed in the prior art. For example, patent document CN116675463A discloses a special early-strength agent for solid waste-based cementitious materials prepared using tailings waste. This agent reacts with steel slag, desulfurized gypsum, etc., to generate hydrated calcium silicate gel and ettringite, thereby improving early strength. Patent document CN116803939A discloses a crack-resistant synergist suitable for solid waste-based concrete, formulated using a blend of multiple chemical components such as alum, basic aluminum sulfate, and anhydrous calcium sulfoaluminate, to solve the problems of low early strength and slow setting and hardening rate.

[0005] In summary, existing technologies for improving the early performance of solid waste-based cementitious materials generally rely on the addition of external components such as chemical early-strength agents or coagulants. While these methods have achieved some success, they have also brought new problems: on the one hand, they significantly increase the material preparation cost, and on the other hand, they increase the overall carbon emission level of the system, which deviates from the original intention of developing low-carbon and waste-utilizing solid waste-based cementitious materials.

[0006] Therefore, there is an urgent need in this field for a new technical solution that can effectively solve the problems of long setting time and low early strength of solid waste-based cementitious materials without introducing additional chemical activators and coagulants, while taking into account cost-effectiveness and low-carbon environmental protection requirements. Summary of the Invention

[0007] This invention provides a solid waste-based cementitious material based on carbonized magnesium slag, its preparation method, and its application, in order to solve the above-mentioned problems existing in the prior art.

[0008] According to a first aspect of the present invention, the present invention provides a solid waste-based cementitious material based on magnesium slag, comprising the following raw materials in parts by weight: 33-60 parts of slag, 15-35 parts of steel slag, 8-20 parts of gypsum and 10-25 parts of magnesium slag.

[0009] The solid waste-based cementitious material provided by this invention belongs to a complete solid waste cementitious material system. Its formulation does not require the addition of early-strength agents and accelerators, significantly reducing cementitious material costs and exhibiting carbon sequestration and reduction properties. Furthermore, this novel solid waste-based cementitious material can flexibly and conveniently control its mineralization degree through the magnesium slag carbon mineralization process. This allows for the coupled enhancement of setting time and mechanical strength through the synergistic effect of chemical and mineral composition and particle size distribution among multiple solid waste cementitious materials, further enabling multi-path applications under different application scenarios and working conditions. The components in this solid waste-based cementitious material have synergistic effects, not only allowing for flexible and effective shortening and control of setting time according to construction conditions and application scenarios, but also exhibiting high early strength, significantly improved later strength, and excellent mechanical properties. This effectively improves the resource utilization level of bulk industrial solid waste and is of great significance for promoting the green, low-carbon, and waste-utilization development of the building materials industry. In this invention, the weight of slag is 33 to 60 parts, for example, 33 parts, 35 parts, 38 parts, 40 parts, 43 parts, 45 parts, 48 ​​parts, 50 parts, 53 parts, 55 parts, 58 parts or 60 parts, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0010] In this invention, the weight of steel slag is 15 to 35 parts, for example, it can be 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34 or 35 parts, as well as specific values ​​between the above-mentioned values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0011] In this invention, the weight of gypsum is 8 to 20 parts, for example, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20 parts, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0012] In this invention, the weight parts of the carbide magnesium slag are 10 to 25 parts, for example, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24 or 25 parts, as well as specific values ​​between the above-mentioned values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0013] In some specific embodiments of the present invention, the solid waste-based cementitious material based on carbide magnesium slag includes the following raw materials in parts by weight: 40-55 parts of slag, 16-20 parts of steel slag, 12-15 parts of gypsum, and 16-24 parts of carbide magnesium slag.

[0014] According to the solid waste-based cementitious material based on carbonized magnesium slag of the present invention, the carbonized magnesium slag is obtained by magnesium slag through a carbonization reaction; by mass parts, the magnesium slag includes: 40-58 parts CaO, 20-30 parts SiO2, 2-5 parts Fe2O3 and 2-8 parts MgO.

[0015] In this invention, the mechanism by which carbonized magnesium slag, as a key component, regulates the coagulation characteristics and enhances the mechanical strength of the entire solid waste-based cementitious material system is as follows: The magnesium slag of this invention (e.g., Pidgeon process magnesium slag) mainly consists of γ-C2S, β-C2S, and small amounts of magnesium silicate phase, calcium hydroxide, magnesium hydroxide, and magnesium oxide. These minerals all exhibit carbon mineralization activity, with γ-C2S and β-C2S, which have high carbonization activity, comprising over 75% by mass. The carbon mineralization process of this invention primarily utilizes the short-term, rapid mineralization reaction between its contained calcium silicate minerals and high-purity or CO2-containing industrial kiln flue gas under specific process conditions, generating a large amount of nano-calcium carbonate and nano-silica gel. Nano-calcium carbonate exhibits several advantages, including: a nucleation effect (nano-CaCO3 particles provide numerous nucleation sites for the formation of hydration products such as C-(A)-SH gel in multi-component solid waste cementitious materials, accelerating the hydration reaction rate of tricalcium silicate in steel slag and blast furnace slag, resulting in earlier and more uniform formation and distribution of hydration products, thus rapidly forming a dense structure and enhancing early strength); a physical filling effect (nano-scale CaCO3 particles can fill the spaces between cementitious material particles and in micron-sized capillaries, optimizing the particle size distribution, refining pore size, reducing porosity, and making the matrix more compact); and a highly active chemical effect (nano-CaCO3 can react with the aluminum phase in cementitious materials to form hydrated calcium aluminate carbohydrate, which is more stable than the usual hydration product ettringite. These products help fill the pores of the system and increase the density of the structure), significantly improving early strength and also having a certain enhancing effect on later strength. Regarding setting time, nano-CaCO3 mainly shortens the setting time by providing nucleation sites to guide and accelerate the hydration process of multi-component solid waste cementitious materials through crystal nucleation effect, chemical effect, and physical filling effect.

[0016] Another major product of the carbon mineralization reaction of magnesium slag is nano-silica gel, which has an amorphous structure and extremely high pozzolanic activity. Nano-silica gel significantly enhances the early and late mechanical strength of solid waste cementitious materials, primarily through the highly active pozzolanic effect (a secondary hydration reaction with calcium hydroxide produced during the hydration of solid waste cementitious materials, resulting in more and denser C-(A)-SH gel), the ultrafine aggregate filling effect (filling smaller pores, making the cementitious material matrix structure denser), and the interface transition zone improvement effect (refining the pore structure of the aggregate-slurry interface transition zone, strengthening the interface transition zone). Regarding setting time, nano-silica gel also promotes rapid setting of calcium-silicon-aluminum-sulfate solid waste-based cementitious materials through highly active pozzolanic reaction, high specific surface area, and micro-aggregate filling effect.

[0017] In summary, the nanoscale calcium carbonate and silica gel generated by the carbonization reaction of calcium silicate mineral phase in magnesia slag with CO2 greatly improves the hydration rate, hydration products and pore structure of multi-component solid waste cementitious materials through multiple effects such as "chemical nucleation + physical filling + volcanic ash activity". This regulates the setting time and mechanical strength, resulting in shorter setting time, significantly improved early strength and stable increase in later strength of solid waste-based cementitious materials based on magnesia slag.

[0018] Preferably, the magnesium slag further comprises, by mass parts: 0.01~5 parts Al2O3 and 0.01~1 parts SO3.

[0019] Preferably, the specific surface area of ​​the magnesium slag is 400–600 m². 2 / kg.

[0020] According to the solid waste-based cementitious material based on magnesium slag mineralization of the present invention, the slag comprises, by mass parts: 25-40 parts CaO, 25-35 parts SiO2, 14-25 parts Al2O3, 0.2-1 parts Fe2O3 and 2-12 parts MgO.

[0021] In this invention, the composition of slag has been optimized to ensure that the cementitious material system has sufficient and highly active silica-alumina components, which is beneficial to improving the strength and durability of the cementitious material.

[0022] Preferably, the slag further includes 0.01 to 2.5 parts of SO3 by weight.

[0023] Preferably, the slag is S95 or higher grade slag, with a specific surface area of ​​400–600 m². 2 / kg.

[0024] According to the solid waste-based cementitious material based on carbide magnesium slag of the present invention, the steel slag comprises, by mass parts: 30-40 parts CaO, 10-18 parts SiO2, 5-8 parts Al2O3, 10-25 parts Fe2O3, and 2-10 parts MgO.

[0025] Preferably, the steel slag further includes 0.01 to 2 parts of SO3 by weight.

[0026] Preferably, the specific surface area of ​​the steel slag is 400–600 m². 2 / kg.

[0027] According to the solid waste-based cementitious material based on magnesia slag of the present invention, the steel slag is converter steel slag or electric furnace steel slag, and has been treated by magnetic separation to remove iron.

[0028] The solid waste-based cementitious material based on magnesium slag mineralization according to the present invention comprises the following raw materials in parts by weight: 0.01 to 10 parts of fly ash.

[0029] In this invention, the weight of fly ash is 0.01 to 10 parts, for example, it can be 0.01 parts, 0.05 parts, 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts or 10 parts, as well as specific values ​​between the above-mentioned values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0030] This invention incorporates fly ash as an optional component into the system. Introducing fly ash into cementitious materials has two advantages: firstly, it can consume the calcium hydroxide produced during hydration, generating more gel phase and helping to improve the material's later-stage strength and durability; secondly, fly ash can improve the workability and blending properties of freshly mixed slurry.

[0031] In some specific embodiments of the present invention, the solid waste-based cementitious material based on magnesia slag includes the following raw materials in parts by weight: 43-54 parts of slag, 16-20 parts of steel slag, 12-15 parts of gypsum, 10-25 parts of magnesia slag and 4-6 parts of fly ash.

[0032] More preferably, the solid waste-based cementitious material based on carbohydrate magnesium slag includes the following raw materials in parts by weight: 48-52 parts slag, 15-18 parts steel slag, 12-14 parts gypsum, 15-18 parts carbohydrate magnesium slag, and 5-6 parts fly ash.

[0033] More preferably, the solid waste-based cementitious material based on magnesia slag includes the following raw materials in parts by weight: 50 parts slag, 16 parts steel slag, 12 parts gypsum, 16 parts magnesia slag and 6 parts fly ash.

[0034] The fly ash comprises, by mass parts: 2-15 parts CaO, 40-50 parts SiO2, 20-40 parts Al2O3, and 2-12 parts Fe2O3.

[0035] Preferably, the fly ash further comprises, by weight, 0.01-2 parts of MgO and 0.01-1.5 parts of SO3.

[0036] Preferably, the specific surface area of ​​the fly ash is 400–600 m². 2 / kg.

[0037] According to the solid waste-based cementitious material based on carbonized magnesium slag of the present invention, the fly ash is fine ash collected from coal-fired power generation in pulverized coal furnaces.

[0038] According to the solid waste-based cementitious material based on magnesium slag mineralization of the present invention, the gypsum is one or more of desulfurized gypsum, phosphogypsum, and fluorogypsum, and its specific surface area is 300-600 m². 2 / kg, of which the mass fraction of CaSO4·2H2O is ≥80%.

[0039] In this invention, gypsum can react with the aluminate phase in the system to form ettringite. The ettringite can further react with calcium carbonate, a carbonation product in the carbonized magnesium slag, to form hydrated calcium aluminocarboxylate, which is more stable than conventional ettringite. The composite and interwoven growth of these products helps fill the pores in the material system, increasing the density of the hardened structure. This not only significantly contributes to the early strength of the material but also plays a role in micro-expansion and compensating for shrinkage, simultaneously improving the volume stability and mechanical properties of the hardened material. Using industrial by-product gypsum also conforms to the design principles of total solid waste and low cost.

[0040] According to the solid waste-based cementitious material based on magnesia slag of the present invention, the initial setting time of the solid waste-based cementitious material based on magnesia slag is 134-227 min, and the final setting time is 228-565 min.

[0041] According to a second aspect of the present invention, the present invention also provides a method for preparing the above-mentioned solid waste-based cementitious material based on carbonized magnesium slag, comprising the following steps: Magnesium slag is prepared by carbon mineralization reaction using magnesium slag as raw material. Slag, steel slag, gypsum and the aforementioned carbide magnesium slag are mixed to obtain a solid waste-based cementitious material based on carbide magnesium slag.

[0042] This invention leverages the high alkalinity and high carbonization activity of industrial solid waste magnesium slag to efficiently process it, obtaining carbonized magnesium slag with varying degrees of mineralization. It then fully utilizes the synergistic effect among the components of the solid waste-based cementitious material to prepare a novel multi-component composite solid waste-based cementitious material containing steel slag, blast furnace slag, carbonized magnesium slag, and gypsum. This provides a solid waste-based cementitious material and its preparation method with a flexible setting time over a wide range and simultaneous improvement in early and late mechanical strength, effectively solving the technical problems of long setting and hardening times and slow early strength development in traditional solid waste-based cementitious materials.

[0043] According to the preparation method of solid waste-based cementitious material based on carbonized magnesium slag of the present invention, the preparation method of the carbonized magnesium slag is as follows: under sealed stirring conditions, magnesium slag and water are mixed in a mass ratio of 1:(0.05~0.2) (preferably 1:(0.1~0.15)), and then CO2 gas is introduced to carry out carbon mineralization reaction. The volume concentration of CO2 gas is controlled to be ≥40% (preferably ≥50%, more preferably 50~90%), the temperature of CO2 gas is 5~60℃ (preferably 35~40℃), the CO2 introduction rate is 0.5-5L / min (preferably 1-3L / min), and the CO2 introduction time is 1~60min (preferably 5~50min, more preferably 20~50min); after the CO2 introduction is completed, stirring is continued for 1~5min (preferably 1~3min).

[0044] In the preparation method of carbonized magnesium slag provided by this invention, the magnesium slag undergoes carbonization activation via CO2. The selected magnesium slag mainly contains alkaline mineral phases γ-C2S and β-C2S, which have low early hydration activity but significantly higher carbonization activity than other mineral phases. Under suitable water content conditions, carbonization reaction can occur immediately after CO2 is introduced, generating high heat of carbonization reaction and a high system temperature. In a short time, a large amount of nanoscale calcium carbonate and amorphous silica gel can be generated through the carbonization reaction, which are uniformly distributed in the carbonized magnesium slag powder particles. In the subsequent hydration process of adding solid waste-based cementitious materials, these gels play a role in inducing nucleation, accelerating hydration, filling with fine particles, and promoting slurry coagulation. Carbon-mineralized magnesium slag containing nano-sized microcrystalline calcium carbonate and amorphous pozzolanic active silica gel can promote a series of reactions in solid waste-based cementitious materials, such as the dissolution of Ca ions in calcareous solid waste mineral phases like steel slag and the dissociation of Si and Al groups in siliceous aluminous solid waste mineral phases like blast furnace slag and fly ash. This accelerates the hydration and hardening process, shortens setting time, reduces porosity, and creates a denser structure, significantly improving early strength and promoting steady growth in later strength. After solid waste-based cementitious materials are formed, conventional curing allows the calcium silicate in the steel slag and magnesium slag to further hydrate and provide alkalinity, thus maintaining a stable pH value and eliminating any risk of steel reinforcement corrosion.

[0045] According to the preparation method of solid waste-based cementitious material based on carbide magnesium slag of the present invention, the CO2 used in preparing the carbide magnesium slag can be high-purity CO2 gas or CO2 flue gas captured from industrial emission sources.

[0046] According to the preparation method of solid waste-based cementitious material based on magnesium slag carbide according to the present invention, the CO2 flue gas captured by the industrial emission source can be kiln flue gas generated in the fields of metal smelting, thermal power, cement manufacturing, etc., with a CO2 content ≥40%; According to the preparation method of solid waste-based cementitious material based on carbide magnesium slag of the present invention, the emission of pollutants from kiln flue gas should meet the limit requirements of the "Emission Standard of Air Pollutants for Industrial Kilns" (GB 8079).

[0047] According to the preparation method of solid waste-based cementitious material based on magnesium slag carbide according to the present invention, slag, steel slag and gypsum are mixed and ground to a specific surface area of ​​400~600 m². 2 / kg and then mix with the carbonized magnesium slag.

[0048] Preferably, when the solid waste-based cementitious material based on carbide magnesium slag further includes fly ash, the slag, steel slag, fly ash, and gypsum are mixed and ground to a specific surface area of ​​400-600 m². 2 / kg and then mix with the carbonized magnesium slag.

[0049] According to the preparation method of solid waste-based cementitious material based on carbonized magnesium slag of the present invention, if the specific surface area of ​​the slag or steel slag is not 400-600 m² 2 / kg, the specific surface area of ​​gypsum is not 300-600 m² 2 At a density of / kg, slag and steel slag are ground separately to a specific surface area of ​​400–600 m². 2 / kg, gypsum ground to a specific surface area of ​​300-600 m² 2 / kg and then mix with the carbonized magnesium slag.

[0050] Preferably, when the solid waste-based cementitious material based on carbide magnesium slag further includes fly ash, the specific surface area of ​​the slag, steel slag, and fly ash is not 400–600 m². 2 / kg, the specific surface area of ​​gypsum is not 300-600 m² 2 At a density of / kg, slag, steel slag, and fly ash are ground separately to a specific surface area of ​​400–600 m². 2 / kg, gypsum ground to a specific surface area of ​​300-600 m² 2 / kg and then mix with the carbonized magnesium slag.

[0051] According to the preparation method of solid waste-based cementitious material based on magnesia slag of the present invention, if the specific surface area of ​​slag, steel slag and fly ash is independently 400-600 m² 2 / kg, the specific surface area of ​​gypsum is 300-600 m² / kg. 2 At a concentration of / kg, slag, steel slag, fly ash, gypsum, and carbide magnesium slag can be mixed directly without grinding.

[0052] According to a third aspect of the present invention, the present invention also provides the application of the above-described solid waste-based cementitious material based on magnesium slag or the solid waste-based cementitious material based on magnesium slag prepared by the above-described preparation method in cement products or concrete.

[0053] The present invention also provides the above-mentioned solid waste-based cementitious material based on carbonized magnesium slag, which can replace cement or conventional mineral admixtures in various construction projects to prepare cement products or concrete.

[0054] The beneficial effects of this invention are: The solid waste-based cementitious material based on magnesia slag provided by this invention uses industrial solid waste such as slag, steel slag, gypsum, fly ash, and magnesia slag as raw materials. It has a low resource and environmental impact, requires no early-strength agents or accelerators, and significantly saves on raw material costs. This solid waste-based cementitious material not only solves the problems of long setting time and low early strength of general solid waste-based cementitious materials by accelerating the hydration process and increasing the proportion of crystalline phase in the hydration products, but also reduces the self-shrinkage of the product and lowers the risk of later cracking.

[0055] This invention provides a method for preparing solid waste-based cementitious materials based on carbonized magnesium slag. The method involves pre-carbonizing magnesium slag using a specific process, transforming it into carbonized magnesium slag containing a large amount of nano-sized microcrystalline calcium carbonate and amorphous high-volcanic ash active silica gel. A novel solid waste-based cementitious material is then prepared through optimized combination of multiple components: steel slag, blast furnace slag, fly ash, carbonized magnesium slag, and gypsum. This method optimizes and improves the setting time and mechanical strength of the cementitious material from multiple dimensions, including material composition, workability, hardened body structure, and carbon load. Furthermore, the setting time of the solid waste-based cementitious material can be flexibly controlled by adjusting the mineralization process of the magnesium slag and the proportions of the multiple components, meeting the application requirements of solid waste-based cementitious materials in different application scenarios and working conditions. This method is of great significance and value for realizing the large-scale and resource-based utilization of bulk industrial solid waste.

[0056] The solid waste-based cementitious material based on carbonized magnesium slag provided by this invention can permanently and stably solidify and seal CO2 from industrial emission sources during its preparation process, which can play an efficient and feasible role in reducing the carbon footprint of industrial sectors that emit CO2, solid waste-based cementitious materials and their products. Detailed Implementation

[0057] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0058] In the following examples and comparative examples, the blast furnace slag is blast furnace ironmaking quenching slag, which has undergone magnetic separation to remove iron, and has an activity grade of S95 with a specific surface area of ​​480 m². 2 / kg, the main components include CaO 38.47 by mass, SiO2 32.31 by mass, Al2O3 18.63 by mass, Fe2O3 0.65 by mass, MgO 7.89 by mass, and SO3 1.55 by mass.

[0059] The steel slag is converter steel slag, which has undergone magnetic separation to remove iron, and has a specific surface area of ​​450 m². 2 / kg, the main components include CaO 35.14 by mass, SiO2 16.70 by mass, Al2O3 7.05 by mass, Fe2O3 23.18 by mass, MgO 7.60 by mass, and SO3 0.55 by mass.

[0060] Fly ash is the fine ash collected from coal-fired power plants using pulverized coal boilers, with a specific surface area of ​​460 m². 2 / kg, the main components include CaO 4.43 by mass, SiO2 42.85 by mass, Al2O3 35.81 by mass, Fe2O3 3.49 by mass, MgO 0.75 by mass, SO3 0.65 by mass; The industrial by-product gypsum is desulfurized gypsum with a specific surface area of ​​410 m². 2 / kg, of which the mass fraction of CaSO4·2H2O is 92%.

[0061] Magnesia slag is produced by the Pidgeon process for magnesium smelting, with a specific surface area of ​​485 m². 2 / kg, the main components include CaO 50.15 parts by mass, SiO2 26.90 parts by mass, Al2O3 0.78 parts by mass, Fe2O3 3.01 parts by mass, MgO 4.01 parts by mass, and SO3 0.05 parts by mass.

[0062] The preparation methods of solid waste-based cementitious materials based on carbonized magnesium slag described in the following examples are uniformly as follows: S1. Grind magnesium slag powder to a specific surface area of ​​485 m² 2 / kg, dried; S2. Weigh the ground magnesium slag powder and water in a ratio of 1:(0.05-0.2), pour them into a closed stirring device, start the stirring device, and introduce CO2 gas into the closed stirring device to carry out the mineralization reaction. The volume concentration of CO2 gas is ≥40%, the temperature of CO2 gas is 5-60℃, the CO2 introduction rate is 0.5-5L / min, and the CO2 introduction time is 1-60 min. After the CO2 introduction is completed, continue to stir in a closed manner for 1-5 min. Then take out the mineralized magnesium slag powder and disperse it by slight extrusion to obtain carbonized magnesium slag A.

[0063] S3. Weigh the blast furnace slag powder, steel slag powder, fly ash, and industrial by-product gypsum according to the specified proportions and mix them evenly to obtain mixed powder B.

[0064] S4. Mix the carbonized magnesium slag A and the mixed powder B in a uniform mass ratio to obtain a solid waste-based cementitious material based on carbonized magnesium slag.

[0065] Example 1 This embodiment provides a solid waste-based cementitious material based on carbide magnesium slag, which, by mass, includes 53 parts of blast furnace slag, 20 parts of steel slag, 15 parts of industrial by-product gypsum, and 12 parts of carbide magnesium slag.

[0066] This embodiment also provides a method for preparing the solid waste-based cementitious material based on carbonized magnesium slag, including the following steps: (1) Preparation of carbonized magnesium slag: 485 m² of specific surface area 2 / kg of magnesium slag powder and water were weighed and added to a closed mixer at a mass ratio of 1:0.1. After the mixing started, CO2 gas was introduced into the closed mixer at a volume concentration of 90%, a temperature of 40℃, a CO2 introduction rate of 2L / min, and a CO2 introduction time of 5min. After the CO2 introduction was completed, the closed mixing continued for 2min. After that, the mineralized magnesium slag powder was taken out and slightly compressed and dispersed to obtain carbonized magnesium slag A.

[0067] (2) Weigh the blast furnace slag powder, steel slag powder and industrial by-product gypsum according to the proportion and mix them evenly to obtain mixed powder B.

[0068] (3) Mix the carbonized magnesium slag A and the mixed powder B evenly to obtain a solid waste-based cementitious material based on carbonized magnesium slag.

[0069] Example 2 This embodiment provides a solid waste-based cementitious material based on carbide magnesium slag, which, by mass, includes 53 parts of blast furnace slag, 20 parts of steel slag, 15 parts of industrial by-product gypsum, and 16 parts of carbide magnesium slag.

[0070] This embodiment also provides a method for preparing the solid waste-based cementitious material based on carbonized magnesium slag, including the following steps: (1) Preparation of carbonized magnesium slag: 485 m² of specific surface area 2 / kg of magnesium slag powder and water were weighed and added to a closed mixer at a mass ratio of 1:0.1. After the mixing started, CO2 gas was introduced into the closed mixer at a volume concentration of 90%, a temperature of 40℃, a CO2 introduction rate of 2L / min, and a CO2 introduction time of 5min. After the CO2 introduction was completed, the closed mixing continued for 2min. After that, the mineralized magnesium slag powder was taken out and slightly compressed and dispersed to obtain carbonized magnesium slag A.

[0071] (2) Weigh the blast furnace slag powder, steel slag powder and industrial by-product gypsum according to the proportion and mix them evenly to obtain mixed powder B.

[0072] (3) Mix magnesium slag A and mixed powder B evenly to obtain solid waste-based cementitious material based on magnesium slag.

[0073] Example 3 This embodiment provides a solid waste-based cementitious material based on carbide magnesium slag, which, by mass, includes 45 parts of blast furnace slag, 16 parts of steel slag, 15 parts of industrial by-product gypsum, and 24 parts of carbide magnesium slag.

[0074] This embodiment also provides a method for preparing the solid waste-based cementitious material based on carbonized magnesium slag, including the following steps: (1) Preparation of carbonized magnesium slag: 485 m² of specific surface area 2 / kg of magnesium slag powder and water were weighed and added to a closed mixer at a mass ratio of 1:0.1. After the mixing started, CO2 gas was introduced into the closed mixer at a volume concentration of 90%, a temperature of 40℃, a CO2 introduction rate of 2L / min, and a CO2 introduction time of 5min. After the CO2 introduction was completed, the closed mixing continued for 2min. After that, the mineralized magnesium slag powder was taken out and slightly compressed and dispersed to obtain carbonized magnesium slag A.

[0075] (2) Weigh the blast furnace slag powder, steel slag powder and industrial by-product gypsum according to the proportion and mix them evenly to obtain mixed powder B.

[0076] (3) Mix magnesium slag A and mixed powder B evenly to obtain solid waste-based cementitious material based on magnesium slag.

[0077] Example 4 This embodiment provides a solid waste-based cementitious material based on magnesia slag, which, by mass, includes 50 parts of blast furnace slag, 16 parts of steel slag, 12 parts of industrial by-product gypsum, 6 parts of fly ash, and 16 parts of magnesia slag.

[0078] This embodiment also provides a method for preparing the solid waste-based cementitious material based on carbonized magnesium slag, including the following steps: (1) Preparation of carbonized magnesium slag: 485 m² of specific surface area 2 / kg of magnesium slag powder and water were weighed and added to a closed mixer at a mass ratio of 1:0.1. After the mixing started, CO2 gas was introduced into the closed mixer at a volume concentration of 90%, a temperature of 40℃, a CO2 introduction rate of 2L / min, and a CO2 introduction time of 5min. After the CO2 introduction was completed, the closed mixing continued for 2min. After that, the mineralized magnesium slag powder was taken out and slightly compressed and dispersed to obtain carbonized magnesium slag A.

[0079] (2) Weigh the blast furnace slag powder, steel slag powder, industrial by-product gypsum and fly ash in proportion and mix them evenly to obtain mixed powder B.

[0080] (3) Mix the magnesia slag A and the mixed powder B evenly to obtain a solid waste-based cementitious material based on magnesia slag.

[0081] Example 5 This embodiment provides a solid waste-based cementitious material based on magnesia slag, which, by mass, includes 50 parts of blast furnace slag, 16 parts of steel slag, 12 parts of industrial by-product gypsum, 6 parts of fly ash, and 16 parts of magnesia slag.

[0082] This embodiment also provides a method for preparing the solid waste-based cementitious material based on carbonized magnesium slag, including the following steps: (1) Preparation of carbonized magnesium slag: 485 m² of specific surface area 2 / kg of magnesium slag powder and water were weighed and added to a closed mixer at a mass ratio of 1:0.15. After the mixing started, CO2 gas was introduced into the closed mixer at a volume concentration of 50%, a temperature of 35℃, a CO2 introduction rate of 2L / min, and a CO2 introduction time of 5min. After the CO2 introduction was completed, the closed mixer was continued to be stirred for 2min. After that, the mineralized magnesium slag powder was taken out and slightly compressed and dispersed to obtain carbonized magnesium slag A.

[0083] (2) Weigh the blast furnace slag powder, steel slag powder, industrial by-product gypsum and fly ash in proportion and mix them evenly to obtain mixed powder B.

[0084] (3) Mix the carbonized magnesium slag A and the mixed powder B evenly to obtain a solid waste-based cementitious material based on carbonized magnesium slag.

[0085] Example 6 This embodiment provides a solid waste-based cementitious material based on magnesia slag, which, by mass, includes 50 parts of blast furnace slag, 16 parts of steel slag, 12 parts of industrial by-product gypsum, 6 parts of fly ash, and 16 parts of magnesia slag.

[0086] This embodiment also provides a method for preparing the solid waste-based cementitious material based on carbonized magnesium slag, including the following steps: (1) Preparation of carbonized magnesium slag: 485 m² of specific surface area 2 / kg of magnesium slag powder and water were weighed and added to a closed mixer at a mass ratio of 1:0.1. After the mixing started, CO2 gas was introduced into the closed mixer at a volume concentration of 90%, a temperature of 35℃, a CO2 introduction rate of 2L / min, and a CO2 introduction time of 20min. After the CO2 introduction was completed, the closed mixing continued for 2min. After that, the mineralized magnesium slag powder was taken out and slightly compressed and dispersed to obtain carbonized magnesium slag A.

[0087] (2) Weigh the blast furnace slag powder, steel slag powder, industrial by-product gypsum and fly ash in proportion and mix them evenly to obtain mixed powder B.

[0088] (3) Mix the carbonized magnesium slag A and the mixed powder B evenly to obtain a solid waste-based cementitious material based on carbonized magnesium slag.

[0089] Example 7 This embodiment provides a solid waste-based cementitious material based on magnesia slag, which, by mass, includes 50 parts of blast furnace slag, 16 parts of steel slag, 12 parts of industrial by-product gypsum, 6 parts of fly ash, and 16 parts of magnesia slag.

[0090] This embodiment also provides a method for preparing the solid waste-based cementitious material based on carbonized magnesium slag, including the following steps: (1) Preparation of carbonized magnesium slag: 485 m² of specific surface area 2 / kg of magnesium slag powder and water were weighed and added to a closed mixer at a mass ratio of 1:0.1. After the mixing started, CO2 gas was introduced into the closed mixer at a volume concentration of 90%, a temperature of 40℃, a CO2 introduction rate of 2L / min, and a CO2 introduction time of 50min. After the CO2 introduction was completed, the closed mixing continued for 2min. After that, the mineralized magnesium slag powder was taken out and slightly compressed and dispersed to obtain carbonized magnesium slag A.

[0091] (2) Weigh the blast furnace slag powder, steel slag powder, industrial by-product gypsum and fly ash in proportion and mix them evenly to obtain mixed powder B.

[0092] (3) Mix the carbonized magnesium slag A and the mixed powder B evenly to obtain a solid waste-based cementitious material based on carbonized magnesium slag.

[0093] Example 8 This embodiment provides a solid waste-based cementitious material based on carbide magnesium slag, which differs from Embodiment 7 only in that, by mass parts, it includes 54 parts of blast furnace slag, 20 parts of steel slag, 12 parts of industrial by-product gypsum, 4 parts of fly ash, and 10 parts of carbide magnesium slag.

[0094] This embodiment also provides a method for preparing the solid waste-based cementitious material based on carbonized magnesium slag, including the following steps: (1) Preparation of carbonized magnesium slag: 485 m² of specific surface area 2 / kg of magnesium slag powder and water were weighed and added to a closed mixer at a mass ratio of 1:0.1. After the mixing started, CO2 gas was introduced into the closed mixer at a volume concentration of 90%, a temperature of 35℃, a CO2 introduction rate of 2L / min, and a CO2 introduction time of 20min. After the CO2 introduction was completed, the closed mixing continued for 2min. After that, the mineralized magnesium slag powder was taken out and slightly compressed and dispersed to obtain carbonized magnesium slag A.

[0095] (2) Weigh the blast furnace slag powder, steel slag powder, industrial by-product gypsum and fly ash in proportion and mix them evenly to obtain mixed powder B.

[0096] (3) Mix the carbonized magnesium slag A and the mixed powder B evenly to obtain a solid waste-based cementitious material based on carbonized magnesium slag.

[0097] Example 9 This embodiment provides a solid waste-based cementitious material based on carbide magnesium slag, which differs from Embodiment 7 only in that, by mass parts, it includes 43 parts of blast furnace slag, 16 parts of steel slag, 12 parts of industrial by-product gypsum, 4 parts of fly ash, and 25 parts of carbide magnesium slag.

[0098] This embodiment also provides a method for preparing the solid waste-based cementitious material based on carbonized magnesium slag, including the following steps: (1) Preparation of carbonized magnesium slag: 485 m² of specific surface area 2 / kg of magnesium slag powder and water were weighed and added to a closed mixer at a mass ratio of 1:0.1. After the mixing started, CO2 gas was introduced into the closed mixer at a volume concentration of 90%, a temperature of 35℃, a CO2 introduction rate of 2L / min, and a CO2 introduction time of 20min. After the CO2 introduction was completed, the closed mixing continued for 2min. After that, the mineralized magnesium slag powder was taken out and slightly compressed and dispersed to obtain carbonized magnesium slag A.

[0099] (2) Weigh the blast furnace slag powder, steel slag powder, industrial by-product gypsum and fly ash in proportion and mix them evenly to obtain mixed powder B.

[0100] (3) Mix the carbonized magnesium slag A and the mixed powder B evenly to obtain a solid waste-based cementitious material based on carbonized magnesium slag.

[0101] Comparative Example 1 This comparative example provides a solid waste-based cementitious material based on carbonized magnesium slag, which, by mass parts, includes 53 parts of blast furnace slag, 32 parts of steel slag, and 15 parts of industrial by-product gypsum.

[0102] This comparative example provides a method for preparing a solid waste-based cementitious material based on carbide magnesium slag, which includes weighing blast furnace slag powder, steel slag powder, and industrial by-product gypsum in proportion and mixing them evenly to obtain the solid waste-based cementitious material.

[0103] Comparative Example 2 This comparative example provides a solid waste-based cementitious material based on carbonized magnesium slag, which, by mass parts, includes 53 parts blast furnace slag, 16 parts steel slag, 15 parts industrial by-product gypsum, and 16 parts magnesium slag.

[0104] This comparative example provides a method for preparing a solid waste-based cementitious material based on carbide-mineralized magnesium slag, which includes weighing blast furnace slag powder, steel slag powder, industrial by-product gypsum, and magnesium slag powder in proportion and mixing them evenly to obtain the solid waste-based cementitious material.

[0105] Comparative Example 3 This comparative example provides a solid waste-based cementitious material based on magnesia slag, which, by mass, includes 50 parts of blast furnace slag, 24 parts of steel slag, 15 parts of industrial by-product gypsum, 6 parts of fly ash, and 5 parts of magnesia slag.

[0106] This comparative example provides a method for preparing the solid waste-based cementitious material based on carbide magnesium slag, comprising the following steps: (1) Preparation of carbonized magnesium slag: 485 m² of specific surface area 2 / kg of magnesium slag powder and water were weighed and added to a closed mixer at a mass ratio of 1:0.1. After the mixing started, CO2 gas was introduced into the closed mixer at a volume concentration of 90%, a temperature of 35℃, a CO2 introduction rate of 2L / min, and a CO2 introduction time of 20min. After the CO2 introduction was completed, the closed mixing continued for 2min. After that, the mineralized magnesium slag powder was taken out and slightly compressed and dispersed to obtain carbonized magnesium slag A.

[0107] (2) Weigh the blast furnace slag powder, steel slag powder, industrial by-product gypsum and fly ash in proportion and mix them evenly to obtain mixed powder B.

[0108] (3) Mix the carbonized magnesium slag A and the mixed powder B evenly to obtain a solid waste-based cementitious material based on carbonized magnesium slag.

[0109] Comparative Example 4 This comparative example provides a solid waste-based cementitious material based on magnesia slag, which, by mass parts, includes 37 parts of blast furnace slag, 15 parts of steel slag, 12 parts of industrial by-product gypsum, 6 parts of fly ash, and 30 parts of magnesia slag.

[0110] This comparative example provides a method for preparing the solid waste-based cementitious material based on carbide magnesium slag, comprising the following steps: (1) Preparation of carbonized magnesium slag: 485 m² of specific surface area 2 / kg of magnesium slag powder and water were weighed and added to a closed mixer at a mass ratio of 1:0.1. After the mixing started, CO2 gas was introduced into the closed mixer at a volume concentration of 90%, a temperature of 35℃, a CO2 introduction rate of 2L / min, and a CO2 introduction time of 20min. After the CO2 introduction was completed, the closed mixing continued for 2min. After that, the mineralized magnesium slag powder was taken out and slightly compressed and dispersed to obtain carbonized magnesium slag A.

[0111] (2) Weigh the blast furnace slag powder, steel slag powder, industrial by-product gypsum and fly ash in proportion and mix them evenly to obtain mixed powder B.

[0112] (3) Mix the carbonized magnesium slag A and the mixed powder B evenly to obtain a solid waste-based cementitious material based on carbonized magnesium slag.

[0113] Comparative Example 5 This comparative example provides a solid waste-based cementitious material based on magnesia slag, comprising, by weight, 50 parts blast furnace slag, 16 parts steel slag, 12 parts industrial by-product gypsum, 6 parts fly ash, and 16 parts magnesia slag.

[0114] This comparative example provides a method for preparing the solid waste-based cementitious material based on carbide magnesium slag, comprising the following steps: (1) Preparation of carbonized magnesium slag: 485 m² of specific surface area 2 / kg of magnesium slag powder and water were weighed and added to a closed mixer at a mass ratio of 1:0.25. After the mixing started, CO2 gas was introduced into the closed mixer at a volume concentration of 90%, a temperature of 35℃, a CO2 introduction rate of 2L / min, and a CO2 introduction time of 20min. After the CO2 introduction was completed, the closed mixing continued for 2min. After that, the mineralized magnesium slag powder was taken out and slightly compressed and dispersed to obtain carbonized magnesium slag A.

[0115] (2) Weigh the blast furnace slag powder, steel slag powder, industrial by-product gypsum and fly ash in proportion and mix them evenly to obtain mixed powder B.

[0116] (3) Mix the carbonized magnesium slag A and the mixed powder B evenly to obtain a solid waste-based cementitious material based on carbonized magnesium slag.

[0117] Comparative Example 6 This comparative example provides a solid waste-based cementitious material based on magnesia slag, comprising, by weight, 50 parts blast furnace slag, 16 parts steel slag, 12 parts industrial by-product gypsum, 6 parts fly ash, and 16 parts magnesia slag.

[0118] This comparative example provides a method for preparing the solid waste-based cementitious material based on carbide magnesium slag, comprising the following steps: (1) Preparation of carbonized magnesium slag: 485 m² of specific surface area 2 / kg of magnesium slag powder and water were weighed and added to a closed mixer at a mass ratio of 1:0.1. After the mixing started, CO2 gas was introduced into the closed mixer at a volume concentration of 20%, a temperature of 40℃, a CO2 introduction rate of 2L / min, and a CO2 introduction time of 20min. After the CO2 introduction was completed, the closed mixer was continued to be stirred for 2min. After that, the mineralized magnesium slag powder was taken out and slightly compressed and dispersed to obtain carbonized magnesium slag A.

[0119] (2) Weigh the blast furnace slag powder, steel slag powder, industrial by-product gypsum and fly ash in proportion and mix them evenly to obtain mixed powder B.

[0120] (3) Mix the carbonized magnesium slag A and the mixed powder B evenly to obtain a solid waste-based cementitious material based on carbonized magnesium slag.

[0121] Comparative Example 7 This comparative example provides a solid waste-based cementitious material based on magnesia slag, comprising, by weight, 50 parts blast furnace slag, 16 parts steel slag, 12 parts industrial by-product gypsum, 6 parts fly ash, and 16 parts magnesia slag.

[0122] This comparative example provides a method for preparing the solid waste-based cementitious material based on carbide magnesium slag, comprising the following steps: (1) Preparation of carbonized magnesium slag: 485 m² of specific surface area 2 / kg of magnesium slag powder and water were weighed and added to a closed mixer at a mass ratio of 1:0.1. After the mixing started, CO2 gas was introduced into the closed mixer at a volume concentration of 90%, a temperature of 35℃, a CO2 introduction rate of 2L / min, and a CO2 introduction time of 90min. After the CO2 introduction was completed, the closed mixing continued for 2min. After that, the mineralized magnesium slag powder was taken out and slightly compressed and dispersed to obtain carbonized magnesium slag A.

[0123] (2) Weigh the blast furnace slag powder, steel slag powder, industrial by-product gypsum and fly ash in proportion and mix them evenly to obtain mixed powder B.

[0124] (3) Mix the carbonized magnesium slag A and the mixed powder B evenly to obtain a solid waste-based cementitious material based on carbonized magnesium slag.

[0125] Comparative Example 8 This comparative example provides a solid waste-based cementitious material based on carbohydrate magnesium slag, which differs from Example 7 only in that an equal amount of steel slag is used to replace carbohydrate magnesium slag.

[0126] Performance testing: The solid waste-based cementitious materials prepared in Examples 1-9 and Comparative Examples 1-8 were subjected to standard consistency water requirement, setting time, and mortar strength tests. The standard consistency water requirement and setting time test methods were in accordance with standard GB / T 1346-2024 "Test Methods for Standard Consistency Water Requirement, Setting Time and Soundness of Cement"; the mortar strength test method was in accordance with GB / T 17671-2021 "Test Methods for Cement Mortar Strength (ISO Method)". When preparing mortar samples, the mortar ratio was 1:3, all cementitious materials were solid waste-based cementitious materials, the water-cement ratio was 0.3, and the same polycarboxylate superplasticizer (solid content 50%) was used in all samples. The amount of superplasticizer added was 1.0% of the mass of the cementitious material. The test results are shown in Table 1 below.

[0127] Table 1 Performance test results of solid waste-based cementitious materials Sample 3d compressive strength / MPa 28-day compressive strength / MPa Initial setting time / min Final setting time / min Stability Example 1 28.6 49.5 227 565 qualified Example 2 30.9 54.7 215 546 qualified Example 3 33.4 53.7 203 518 qualified Example 4 32.0 57.2 182 437 qualified Example 5 29.5 51.4 208 520 qualified Example 6 37.2 59.3 157 383 qualified Example 7 38.5 58.9 134 228 qualified Example 8 35.7 55.8 173 432 qualified Example 9 37.9 59.0 145 350 qualified Comparative Example 1 21.0 40.7 265 645 qualified Comparative Example 2 24.6 45.3 261 613 qualified Comparative Example 3 25.2 47.5 255 604 qualified Comparative Example 4 20.8 42.1 236 572 qualified Comparative Example 5 25.6 46.2 253 602 qualified Comparative Example 6 28.3 51.0 221 568 qualified Comparative Example 7 30.1 50.5 232 575 qualified Comparative Example 8 22.5 42.1 283 676 qualified The experimental results show that the solid waste-based cementitious material prepared using this invention, based on magnesia slag, exhibits superior performance compared to the control sample with the same specific surface area. The initial setting time of this magnesia slag-based cementitious material is 134–227 min, and the final setting time is 228–565 min; the 3-day compressive strength is 28.6–38.5 MPa, and the 28-day compressive strength reaches 49.5–59.3 MPa. Significant early strength growth and stable later strength growth can be achieved without the addition of other early-strength activators or quick-setting agents. Furthermore, the setting time is significantly shorter than that of traditional slag-steel slag-gypsum system solid waste-based cementitious materials, with a wide range of setting time variations, allowing for flexible adjustment of the setting time according to actual application needs and scenarios.

[0128] By controlling the conditions and time of the mineralization preparation process of carbide magnesium slag, it is possible to regulate its mineralization degree, the morphology, size and embedding characteristics of the carbonization products calcium carbonate and amorphous silica gel. Under the premise of significantly shortening the overall setting time of solid waste-based cementitious materials, the setting time of solid waste-based cementitious materials can be well controlled. The setting time is designed to be within a reasonable and controllable range with a certain width, so as to better meet the needs of different working conditions and scenarios in engineering construction for setting in a short time, while ensuring the high early strength and later strength of cementitious materials.

[0129] In summary, the solid waste-based cementitious material and its preparation method based on carbonized magnesium slag provided by this invention not only achieve high early strength and stable growth in later strength, but also effectively shorten the setting time of the solid waste-based cementitious material and control it within a certain range. This expands the pathways and feasibility for the practical application of this solid waste-based cementitious material, and has a very broad prospect for promotion and application. It also has carbon sequestration and carbon reduction effects, resulting in significant economic and ecological benefits.

[0130] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A solid waste-based cementitious material based on carbonized magnesium slag, characterized in that, The raw materials include the following parts by weight: 33-60 parts slag, 15-35 parts steel slag, 8-20 parts gypsum, and 10-25 parts carbide magnesium slag.

2. The solid waste-based cementitious material based on magnesium slag mineralization according to claim 1, characterized in that, The carbonized magnesium slag is obtained by a carbonization reaction of magnesium slag; by mass fraction, the magnesium slag comprises: 40-58 parts CaO, 20-30 parts SiO2, 2-5 parts Fe2O3 and 2-8 parts MgO. Preferably, the magnesium slag further comprises, by weight, 0.01-5 parts Al2O3 and 0.01-1 parts SO3; Preferably, the specific surface area of ​​the magnesium slag is 400–600 m². 2 / kg.

3. The solid waste-based cementitious material based on magnesium slag mineralization according to claim 1 or 2, characterized in that, The slag, by mass, comprises: 25-40 parts CaO, 25-35 parts SiO2, 14-25 parts Al2O3, 0.2-1 parts Fe2O3, and 2-12 parts MgO. Preferably, the slag further comprises, by weight, 0.01 to 2.5 parts of SO3; Preferably, the slag is S95 or higher grade slag, with a specific surface area of ​​400–600 m². 2 / kg.

4. The solid waste-based cementitious material based on carbide magnesium slag according to any one of claims 1-3, characterized in that, The steel slag comprises, by mass, 30-40 parts CaO, 10-18 parts SiO2, 5-8 parts Al2O3, 10-25 parts Fe2O3, and 2-10 parts MgO. Preferably, the steel slag further comprises, by weight, 0.01 to 2 parts of SO3; Preferably, the specific surface area of ​​the steel slag is 400–600 m². 2 / kg.

5. The solid waste-based cementitious material based on magnesium slag mineralization according to any one of claims 1-4, characterized in that, The raw materials include the following parts by weight: 0.01 to 10 parts of fly ash; The fly ash comprises, by weight, 2-15 parts CaO, 40-50 parts SiO2, 20-40 parts Al2O3, and 2-12 parts Fe2O3; Preferably, the fly ash further comprises, by weight parts: 0.01~2 parts MgO and 0.01~1.5 parts SO3; Preferably, the specific surface area of ​​the fly ash is 400–600 m². 2 / kg.

6. The solid waste-based cementitious material based on magnesium slag mineralization according to any one of claims 1-5, characterized in that, The gypsum is one or more of desulfurized gypsum, phosphogypsum, and fluorogypsum, with a specific surface area of ​​300–600 m². 2 / kg, of which the mass fraction of CaSO4·2H2O is ≥80%.

7. The solid waste-based cementitious material based on carbide magnesium slag according to any one of claims 1-6, characterized in that, The initial setting time of the solid waste-based cementitious material based on carbide magnesium slag is 134–227 min, and the final setting time is 228–565 min.

8. The method for preparing solid waste-based cementitious materials based on magnesium slag mineralization according to any one of claims 1-7, characterized in that, Includes the following steps: Magnesium slag is prepared by carbon mineralization reaction using magnesium slag as raw material. Slag, steel slag, gypsum and the aforementioned carbide magnesium slag are mixed to obtain a solid waste-based cementitious material based on carbide magnesium slag.

9. The method for preparing solid waste-based cementitious materials based on carbonized magnesium slag according to claim 8, characterized in that, The preparation method of the carbonized magnesium slag is as follows: Under sealed stirring conditions, magnesium slag and water are mixed in a mass ratio of 1:(0.05~0.2), and then CO2 gas is introduced to carry out the carbonization reaction. The volume concentration of CO2 gas is controlled at ≥40%, the temperature of CO2 gas is 5~60℃, the CO2 introduction rate is 0.5-5L / min, and the CO2 introduction time is 1~60min. After the CO2 introduction is completed, stirring is continued for 1~5min.

10. The application of the solid waste-based cementitious material based on magnesium slag as described in any one of claims 1-7, or the solid waste-based cementitious material based on magnesium slag prepared by the preparation method described in claim 8 or 9, in cement products or concrete.