Method for preparing solid waste cementitious material from micro-carbonized steel slag

Abstract

The application discloses a kind of micro-carbonized steel slag preparation solid waste cementing material method, belong to building material technical field.Preparation method includes: steel slag particle is broken, iron is selected, and steel slag powder is obtained by grinding treatment;Steel slag powder is mixed with water and carbonization additive, and steel slag wet mixture is obtained;Steel slag wet mixture is sent to carbon dioxide curing kettle and is cured and is strongly stirred, and micro-carbonized steel slag particle is obtained by fast carbonization, and then grinding drying is carried out to obtain micro-carbonized steel slag powder;According to micro-carbonized steel slag: 45~70 parts, slag: 15~35 parts, gypsum: 1~8 parts, cement or clinker: 1~8 parts, fly ash or metal tailings: 1~15 parts, alkaline solution: 1~10 parts, water: 25~30 parts, mixed to obtain micro-carbonized steel slag solid waste cementing material.The micro-carbonized solid waste steel slag cementing material prepared by the application has the advantages of low cost, simple preparation process and equipment, good early and late mechanical properties, good stability, low carbon and high added value, etc.

Description

Technical Field

[0001] This invention pertains to the resource utilization of solid waste building materials, specifically involving a method for preparing solid waste cementitious materials from micro-carbonized steel slag. Background Technology

[0002] Steel slag is an industrial byproduct generated during the steelmaking process, accounting for approximately 10% to 16% of crude steel production. my country's steel slag industry is characterized by large production volume, high stockpiling levels, and low comprehensive utilization rates. Long-term stockpiling and disposal of steel slag not only occupies large areas of land, but the heavy metal ions leached from it also pollute the land, damage the soil, and cause water pollution after seeping into groundwater.

[0003] The main chemical components of steel slag typically include CaO and Fe. x O, SiO2, and Al2O3, etc. The main low-activity phase in steel slag is γ-C2S, which has extremely low hydration activity. Free CaO, free MgO, Ca(OH)2, and Mg(OH)2 in steel slag can undergo carbonation reactions to produce calcium carbonate or magnesium carbonate. C3S, CaSiO3, β-C2S, and γ-C2S carbonize to form amorphous SiO2, which is beneficial to improving the stability and enhancing the activity of steel slag.

[0004] Currently, steel carbide slag is used to prepare aggregates and steel carbide slag products. The growth and interweaving of nano-CaCO3 crystals in steel carbide slag can give it high particle strength. Aggregates and bricks prepared from steel carbide slag can have high carbon fixation rate and compressive strength.

[0005] On the other hand, carbide steel slag can be used to prepare admixtures and cementitious materials. The reaction between CO2 and the calcium silicate phase in the steel slag generates CaCO3 and amorphous SiO2. Amorphous SiO2 possesses potential chemical activity; when carbide steel slag is used as a cement admixture, the amorphous SiO2 undergoes a hydration reaction to form hydrated calcium silicate, which helps promote the hydration reaction and strengthen the interface of the cement matrix, thereby improving the mechanical properties of the cementitious material.

[0006] However, the use of carbonized steel slag as a blending material usually requires a high activity index, and places high demands on the carbonization process, the carbonization depth of the steel slag, and the carbonization efficiency. Summary of the Invention

[0007] Purpose of the invention: The technical problem to be solved by the present invention is to provide a method for preparing solid waste cementitious materials from micro-carbonized steel slag, which has high mechanical properties, low carbon content and high added value, and is conducive to promoting the utilization of CO2 and the resource utilization of steel slag solid waste.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0009] A method for preparing solid waste cementitious materials from micro-carburized steel slag includes the following steps:

[0010] Step (1): The steel slag particles are crushed, selected for iron, and ground to obtain steel slag powder, which is then dried after powder selection;

[0011] The steel slag particles are mainly of three types: electric furnace steel slag, open-hearth furnace steel slag, and converter steel slag, or any one or a combination of two or more of them.

[0012] Furthermore, the steel slag particles are crushed using a crusher, and then the iron blocks in the steel slag particles are removed by magnetic separation using an iron remover. The particles are then fed into a ball mill for grinding to 200-300 mesh to obtain steel slag powder, which is then dried at 100-105℃ for more than 24 hours.

[0013] Furthermore, the grinding aid is selected from any one or a combination of two or more of triethanolamine, ethylene glycol, sodium silicate, sodium tripolyphosphate, and sodium polyphosphate; the grinding aid and steel slag powder are mixed at a mass ratio of 0.01~0.05:100.

[0014] Step (2): Mix the steel slag powder and water from step (1) according to the following mass proportions: 100 parts steel slag powder, 0.1~10 parts water, and 1~10 parts carbonization aid to obtain a wet steel slag mixture.

[0015] The water mentioned herein is either tap water or purified water.

[0016] The carbonization aid is any one or a combination of two or more of dilute hydrochloric acid, dilute sulfuric acid, and dilute nitric acid, with a concentration of 0.01~0.1mol / L.

[0017] Step (3): The wet steel slag mixture from step (2) is sent to a carbon dioxide curing kettle, and CO2 gas is introduced. Under CO2 curing conditions, the steel slag powder reacts with CO2 to form carbonization particles.

[0018] The CO2 concentration is 30-99%, and preferably the CO2 gas introduced is 50% or more.

[0019] The CO2 curing conditions are as follows: temperature 20~60℃, CO2 partial pressure 0.1~0.5MPa, and time 3~45 minutes, with 60℃, 0.1MPa, and 30 minutes being preferred.

[0020] Specifically, the steel carbide slag is ball-milled using a planetary ball mill, then passed through a 74μm square hole sieve to obtain steel carbide slag powder, and dried at 100~105℃ for more than 24 hours.

[0021] Step (4): Prepare solid waste cementitious material according to the following parts by mass:

[0022] Micro-carbonized steel slag: 45-70 parts;

[0023] Slag: 15-35 parts;

[0024] Plaster: 1-8 parts;

[0025] Cement or clinker: 1-8 parts;

[0026] Fly ash or metallic tailings: 1-15 parts

[0027] Alkaline solution: 1-10 parts;

[0028] Water: 25-30 parts;

[0029] Weigh, mix, pour, and shape the raw materials according to the above proportions to obtain the final product.

[0030] Preferably, it consists of the following components in parts by mass:

[0031] Carbide steel slag powder: 50-60 parts;

[0032] Slag: 25-35 parts;

[0033] Plaster: 1-5 parts;

[0034] Cement or clinker: 1-5 parts;

[0035] Fly ash or metal tailings: 5-15 parts

[0036] Alkaline solution: 1-5 parts;

[0037] Water: 25-28 parts;

[0038] Preferably, the micro-carburized steel slag is the micro-carburized steel slag powder obtained in step (3), the gypsum is one or a combination of two or more of phosphogypsum, fluorogypsum, and desulfurized gypsum; the cement or clinker is silicate cement or clinker; the fly ash is grade I, II, or III fly ash, and the metal tailings are any one of iron tailings, copper tailings, aluminum tailings, and zinc tailings, with a specific surface area of ​​300~450 m². 2 / g; the alkaline solution is one or more of sodium hydroxide and potassium hydroxide, and the concentration of the alkaline solution is 1~5 mol / L.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] First, this invention employs rapid (3-45 minutes), normal / low pressure (0.1-0.5 MPa) CO2 carbonization of steel slag, resulting in micro-carbonization of the slag with a low degree of carbonization (3%-10%). On one hand, CO2 reacts with free calcium oxide and magnesium oxide in the steel slag, absorbing them and improving the stability of the steel slag. On the other hand, CO2 reacts with some calcium silicate (γ-C2S) phase in the steel slag to generate nano-calcium carbonate and amorphous silica, increasing the reactivity of the steel slag and contributing to the early performance development of carbonized steel slag cementitious materials. At the same time, it retains some silicate (γ-C2S) mineral phases, which contributes to the continuous development of the later performance of carbonized steel slag solid waste cementitious materials.

[0041] Second: In the process of micro-carbonizing steel slag in this invention, the carbonization aids dilute sulfuric acid, dilute hydrochloric acid, and dilute nitric acid will react with the calcium components in the steel slag to generate calcium sulfate (CaSO4), calcium chloride (CaCl2), and calcium nitrate (Ca(NO3)2). Calcium sulfate can play an activating role, reacting with the active Al2O3 in the slag to generate hydrated calcium sulfoaluminate (AFt or AFm) (Equations (1) and (2)). Calcium chloride will also react with the active Al2O3 in the slag to generate hydrated calcium chloroaluminate (Equation (3)), thus playing a "synergistic activation" role between the micro-carbonized steel slag and the slag. At the same time, due to the formation of calcium sulfate in the micro-carbonized steel slag, the gypsum content in this invention is reduced.

[0042] Al2O3+3CaSO4+3Ca(OH)2+29H2O→3CaO∙Al2O3∙3CaSO4∙32H2O (AFt) (1)

[0043] Al2O3+CaSO4+3Ca(OH)2+9H2O→3CaO∙Al2O3∙CaSO4∙12H2O (AFm) (2)

[0044] Al2O3+3CaCl2+3Ca(OH)2+7H2O→3CaO∙Al2O3∙3CaCl2∙10H2O (3).

[0045] Third, this invention utilizes alkaline solutions of potassium hydroxide and sodium hydroxide to provide an alkaline hydration environment in the early stages of the micro-carbonized steel slag solid waste cementitious material. This promotes the hydration reaction of amorphous SiO2, a carbonization product in the micro-carbonized steel slag, and active SiO2 in the slag, generating hydrated calcium silicate and thus promoting the early mechanical property development of the micro-carbonized steel slag solid waste cementitious material. Simultaneously, the use of a small amount of silicate cement or clinker in this invention will also provide an alkaline environment for the micro-carbonized steel slag solid waste cementitious system, promoting the hydration reaction of active SiO2 and further accelerating early performance development.

[0046] Fourth: This invention uses micro-carbonized steel slag to prepare solid waste cementitious materials and constructs a CaO-SiO2-Al2O3-SO3-CO2 cementitious system, which has high early strength and later strength, low volume expansion rate, and good stability. The nano-calcium carbonate generated by the carbonization reaction of steel slag can partially participate in the hydration reaction to generate hydrated calcium aluminate carbohydrate (Hc and Mc) (Equations (4 and 5)), and partially fill the pores and matrix of solid waste cementitious materials to increase the density of the matrix and improve mechanical properties; the nano-SiO2 generated by the carbonization reaction has high activity and fast hydration reaction rate, and participates in the hydration reaction in the early stage to generate hydrated calcium silicate (Equation (6)), promoting the development of early performance of carbonized steel slag solid waste cementitious materials; the γ-C2S in carbonized steel slag has a slow hydration rate, and participates in the hydration reaction in the later stage to generate hydrated calcium silicate and calcium hydroxide (Equation (7)), promoting the development of later performance.

[0047] 3CaO∙Al2O3+CaCO3+11H2O→4CaO∙Al2O3∙CO2∙11H2O (Mc) (4)

[0048] 3CaO∙Al2O3+0.5CaCO3+0.5Ca(OH)2+11.5H2O→4CaO∙Al2O3∙(CO2) 0.5 ∙12H2O (Hc) (5)

[0049] xSiO2+ Ca(OH)2+ (y-1)H2O→CaO∙xSiO2∙yH2O (6)

[0050] xγ-C2S+(y+1)H2O→CaO∙xSiO2∙yH2O+ Ca(OH)2 (7).

[0051] Fifth, the carbonization process of this invention has relatively low requirements. It can adopt a low-pressure (0.1~0.5MPa), low-concentration (50%~99%), and low-temperature (20~60℃) carbonization process, thus allowing the use of industrial exhaust gas CO2, and the carbonization process is easy to implement.

[0052] Sixth, the total content of micro-carbonized steel slag and slag in the micro-carbonized steel slag solid waste cementitious material of this invention is greater than 75%, which has good early and late activity. It can be mixed with some fly ash and low-activity metal tailings, including iron tailings, copper tailings, aluminum tailings, zinc tailings, etc., which is conducive to the resource utilization of metal tailings.

[0053] Seventh, the micro-carbonized steel slag solid waste cementitious material of this invention has the characteristics of low carbon, low cost, and high added value. On the one hand, this invention uses CO2-carbonized steel slag powder, which promotes the resource utilization of carbon dioxide in the field of building materials and has negative carbon properties; on the other hand, it uses a large amount of solid waste (with little or no cement or clinker) to prepare cementitious materials, resulting in low carbon emissions from the carbonized steel slag solid waste cementitious material, which also has low carbon properties; the micro-carbonized steel slag solid waste cementitious material can be used as roadbed material and for preparing building materials, which has high added value; at the same time, it is conducive to promoting the resource utilization and sustainable use of industrial solid waste steel slag, reducing its pollution to the environment, and reducing the pressure on the ecological environment. Attached Figure Description

[0054] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, and the advantages of the present invention in the above and / or other aspects will become clearer.

[0055] Figure 1 This is a flowchart illustrating the preparation process of the carbonized steel slag solid waste cementitious material of the present invention. Detailed Implementation

[0056] The present invention can be better understood from the following embodiments. Comparative Example 1

[0057] A method for preparing solid waste cementitious materials using uncarbonized steel slag includes the following steps:

[0058] (1) Steel slag particles are crushed, selected for iron, and ground to obtain steel slag powder;

[0059] (2) The raw material composition of steel slag solid waste cementitious material is as follows, in percentage by mass:

[0060] Steel slag powder (uncarbonized): 40 parts; slag: 30 parts; gypsum: 15 parts; cement: 15 parts; mix all raw materials thoroughly and evenly.

[0061] (3) Add 30 parts of water to the mixture from step (2);

[0062] (4) Then mix in a cement paste mixer for 3-4 minutes;

[0063] (5) Pour the mixed slurry into the mold and compact it on the cement mortar compaction table for 30-45 seconds;

[0064] (6) Let the mold stand for 1 day to form the sample; demold the formed sample and cure it according to standard until the specified age. Example 1

[0065] Combination Figure 1 The present invention discloses a method for preparing solid waste cementitious materials from micro-carbonized steel slag, comprising the following steps:

[0066] (1) Steel slag particles are crushed, selected for iron, and ground to obtain steel slag powder;

[0067] (2) Mix the steel slag powder and water in step (1) according to the following mass ratios: 100 parts steel slag powder and 10 parts water to obtain a wet steel slag mixture.

[0068] (3) The wet steel slag mixture from step (2) is fed into a carbon dioxide curing kettle, and 50% CO2 gas is introduced. The mixture is carbonized for 30 minutes at 60°C and 0.1 MPa carbonization pressure to obtain carbonized steel slag particles. After grinding and drying, carbonized steel slag powder is obtained.

[0069] (4) The raw material composition of the solid waste cementitious material of carbide steel slag is as follows by mass percentage: micro-carbide steel slag: 40 parts; slag: 30 parts; gypsum: 15 parts; cement or clinker: 15 parts; water: 30 parts; all raw materials are thoroughly mixed evenly.

[0070] (5) Then mix in a cement paste mixer for 3-4 minutes;

[0071] (6) Pour the mixed slurry into the mold and compact it on the cement mortar compaction table for 30-45 seconds;

[0072] (7) Let the mold stand for 1 day to form the sample; demold the formed sample and cure it according to standard. Example 2

[0073] A method for preparing solid waste cementitious materials from micro-carbonized steel slag includes the following steps:

[0074] (1) Steel slag particles are crushed, selected for iron, and ground to obtain steel slag powder;

[0075] (2) Mix the steel slag powder and water in step (1) according to the following mass parts: 100 parts steel slag powder, 5 parts water, and 5 parts carbonization aid to obtain a wet steel slag mixture.

[0076] (3) The wet steel slag mixture from step (2) is fed into a carbon dioxide curing kettle, and 50% CO2 gas is introduced. The mixture is carbonized at 60°C and 0.1 MPa carbonization pressure to obtain carbonized steel slag particles. After grinding and drying, carbonized steel slag powder is obtained.

[0077] (4) The raw material composition of the solid waste cementitious material of steel slag carbide is as follows by mass percentage: micro-carbonized steel slag: 50 parts; slag: 30 parts; gypsum: 5 parts; cement or clinker: 5 parts; fly ash or metal tailings: 10 parts; potassium hydroxide alkaline solution: 5 parts; water: 25 parts;

[0078] (5) Then mix in a cement paste mixer for 3-4 minutes;

[0079] (6) Pour the mixed slurry into the mold and compact it on the cement mortar compaction table for 30-45 seconds;

[0080] (7) Let the mold stand for 1 day to form the sample; demold the formed sample and cure it according to standard. Example 3

[0081] A method for preparing solid waste cementitious materials from micro-carbonized steel slag includes the following steps:

[0082] (1) Steel slag particles are crushed, selected for iron, and ground to obtain steel slag powder;

[0083] (2) Mix the steel slag powder and water in step (1) according to the following mass parts: 100 parts steel slag powder, 5 parts water, and 5 parts carbonization aid to obtain a wet steel slag mixture.

[0084] (3) The wet steel slag mixture from step (2) is fed into a carbon dioxide curing kettle, and 50% CO2 gas is introduced. The mixture is carbonized at 60°C and 0.1 MPa carbonization pressure to obtain carbonized steel slag particles. After grinding and drying, carbonized steel slag powder is obtained.

[0085] (4) The raw material composition of the solid waste cementitious material of steel slag carbide is as follows by mass percentage: micro-carbonized steel slag: 55 parts; slag: 25 parts; gypsum: 5 parts; cement or clinker: 5 parts; fly ash or metal tailings: 10 parts; potassium hydroxide alkaline solution: 5 parts; water: 25 parts;

[0086] (5) Then mix in a cement paste mixer for 3-4 minutes;

[0087] (6) Pour the mixed slurry into the mold and compact it on the cement mortar compaction table for 30-45 seconds;

[0088] (7) Let the mold stand for 1 day to form the sample; demold the formed sample and cure it according to standard. Example 4

[0089] A method for preparing solid waste cementitious materials from micro-carbonized steel slag includes the following steps:

[0090] (1) Steel slag particles are crushed, selected for iron, and ground to obtain steel slag powder;

[0091] (2) Mix the steel slag powder and water in step (1) according to the following mass parts: 100 parts steel slag powder, 5 parts water, and 5 parts carbonization aid to obtain a wet steel slag mixture.

[0092] (3) The wet steel slag mixture from step (2) is fed into a carbon dioxide curing kettle, and 50% CO2 gas is introduced. The mixture is carbonized at 60°C and 0.1 MPa carbonization pressure to obtain carbonized steel slag particles. After grinding and drying, carbonized steel slag powder is obtained.

[0093] (4) The raw material composition of the solid waste cementitious material of steel slag carbide is as follows by mass percentage: micro-carbonized steel slag: 60 parts; slag: 25 parts; gypsum: 5 parts; fly ash or metal tailings: 10 parts; potassium hydroxide alkaline solution: 5 parts; water: 25 parts;

[0094] (5) Then mix in a cement paste mixer for 3-4 minutes;

[0095] (6) Pour the mixed slurry into the mold and compact it on the cement mortar compaction table for 30-45 seconds;

[0096] (7) Let the mold stand for 1 day to form the sample; demold the formed sample and cure it according to standard.

[0097] The degree of carbonization of the steel slag in Comparative Example 1 and Examples 1-4 is shown in the table below.

[0098] Table 1. Carbonization degree (%) of steel slag in Comparative Example 1 and Examples 1-4

[0099]

[0100] The formulations of solid waste cementitious materials in Comparative Example 1 and Examples 1-4 are shown in the table below.

[0101] Table 2 Comparative and Example Formulations (wt. %)

[0102]

[0103] The setting time, strength, and 28-day expansion rate of the solid waste cementitious materials in Comparative Example 1 and Examples 1-4 are as follows.

[0104] Table 3. Setting time, strength, expansion rate, and stability of solid waste cementitious materials in comparative examples and embodiments.

[0105]

[0106] As shown in Table 1, the degree of carbonization of steel slag is calculated based on the carbonization weight gain rate. The weight gain rate of carbonized steel slag is approximately 4%, with about 5% CaO participating in the reaction and about 10% calcium carbonate being formed. The free calcium oxide content in the steel slag of Examples 1-4 is lower than that of Comparative Example 1.

[0107] Compared to the XRD of Comparative Example 1, Example 1 showed diffraction peaks for calcium carbonate, with reduced peak values ​​for calcium hydroxide, free calcium oxide, and free magnesium oxide. This is mainly due to the reaction of CO2 with the free calcium oxide and magnesium oxide in the steel slag, which absorbed some of the free calcium oxide and magnesium oxide. Meanwhile, Example 1 also retained a relatively high C2S diffraction peak, which is beneficial for promoting the development of the mechanical properties of the solid waste cementitious material in the later stages.

[0108] As shown in Table 3, the initial setting time of Examples 1-4 was greater than 45 minutes, and the final setting time was less than 10 hours. The early and later compressive strengths of Examples 1-4 were greater than those of Comparative Example 1, mainly because the amorphous SiO2 formed after the steel slag carbonized in this patent enhances early activity. Simultaneously, the alkaline solution acts as an activator, promoting early strength development. Furthermore, the carbonized steel slag retains a certain amount of C2S, which continues to hydrate in the later stages, thus promoting later strength development. Compared to Comparative Example 1, the expansion rate of Examples 1-4 was significantly reduced, mainly because the free CaO and free MgO in the steel slag underwent a carbonization reaction, generating calcium carbonate and magnesium carbonate, improving volume stability and soundness.

[0109] This invention provides a method for preparing solid waste cementitious materials from micro-carbonized steel slag. Many methods and approaches exist for implementing this technical solution; the above description is merely a preferred embodiment of the invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications should also be considered within the scope of protection of this invention. All components not explicitly stated in this embodiment can be implemented using existing technologies.

Claims

1. A method for preparing solid waste cementitious materials from micro-carburized steel slag, characterized in that, Includes the following steps: (1) Steel slag particles are crushed, selected for iron, and ground with the addition of grinding aids to obtain steel slag powder, which is then dried after powder selection; (2) Mix the steel slag powder from step (1) with water and carbonization aid to obtain a wet steel slag mixture; In step (2), the carbonization aid is any one or a combination of two or more of dilute hydrochloric acid, dilute sulfuric acid, and dilute nitric acid, with a concentration of 0.01~0.1mol / L; the steel slag powder, water, and carbonization aid are mixed in a mass ratio of 100:0.1~10:1~10. (3) The wet steel slag mixture from step (2) is fed into a carbon dioxide curing kettle, CO2 gas is introduced and stirred thoroughly to allow the steel slag to undergo a rapid carbonization reaction with CO2, resulting in micro-carbonized steel slag particles. After grinding, micro-carbonized steel slag powder is obtained; the degree of carbonization of the micro-carbonized steel slag is 3%~10%. In step (3), CO2 gas is introduced into the carbon dioxide curing vessel. The volume concentration of CO2 in the introduced CO2 gas is 30~99%, the pressure is 0.1~0.5MPa, the temperature range is 20~60℃, and the carbonization reaction time is 3~45 minutes. (4) Prepare solid waste cementitious materials according to the following parts by mass: Micro-carburized steel slag powder: 45~70 parts; Slag: 15-35 parts; Plaster: 1-8 parts; Cement or clinker: 1-8 parts; Fly ash or metal tailings: 1-15 parts; Alkaline solution: 1-10 parts; Water: 25-30 parts; Weigh, mix, pour, and shape the raw materials according to the above proportions to obtain the final product.

2. The method for preparing solid waste cementitious materials from micro-carburized steel slag according to claim 1, characterized in that, In step (1), the steel slag particles are selected from any one or a combination of two or more of electric furnace steel slag, open-hearth furnace steel slag, and converter steel slag; the steel slag particles are crushed using a crusher, and then iron blocks in the steel slag particles are removed by magnetic separation using an iron remover. The particles are then fed into a ball mill with grinding aids added to grind the steel slag particles to a specific surface area of ​​300-400 m². 2 / g, to obtain steel slag powder, and dry it at 100~105℃ for more than 24 hours.

3. The method for preparing solid waste cementitious materials from micro-carburized steel slag according to claim 1, characterized in that, In step (1), the grinding aid is selected from any one or a combination of two or more of triethanolamine, ethylene glycol, sodium silicate, sodium tripolyphosphate, and sodium polyphosphate; the grinding aid and steel slag powder are mixed at a mass ratio of 0.01 to 0.05:

100.

4. The method for preparing solid waste cementitious materials from micro-carburized steel slag according to claim 1, characterized in that, In step (3), the carbonized steel slag is ball-milled using a planetary ball mill, then passed through a 74μm square hole sieve to obtain micro-carbonized steel slag powder, and dried at 100~105℃ for more than 24 hours.

5. The method for preparing solid waste cementitious materials from micro-carburized steel slag according to claim 1, characterized in that, In step (4), the gypsum is one or a combination of two or more of phosphogypsum, fluorogypsum, and desulfurized gypsum, and the cement or clinker is silicate cement or clinker.

6. The method for preparing solid waste cementitious materials from micro-carburized steel slag according to claim 1, characterized in that, In step (4), the mass of the micro-carbonized steel slag powder and slag accounts for more than 75% of the total mass of all raw material components.

7. The method for preparing solid waste cementitious materials from micro-carburized steel slag according to claim 1, characterized in that, In step (4), the fly ash is grade I, II, or III fly ash, and the metal tailings are any one of iron tailings, copper tailings, aluminum tailings, and zinc tailings, with a specific surface area of ​​300-450 m². 2 / g.

8. The method for preparing solid waste cementitious materials from micro-carburized steel slag according to claim 1, characterized in that, In step (4), the alkaline solution is one or more of sodium hydroxide and potassium hydroxide, and the concentration of the alkaline solution is 1~5 mol / L.

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