A hot-quenched steel slag-based multi-solid waste synergistic composite cementitious material and its preparation method

Abstract

This invention provides a hot-quenched steel slag-based multi-solid waste synergistic composite cementitious material and its preparation method, comprising the following steps: preparing ultrafine powders: grinding and sieving the raw materials of the cementitious material to obtain various ultrafine powders; mixing ultrafine coal gangue powder, ultrafine calcium carbide slag powder, and a portion of ultrafine desulfurized gypsum powder, adding water, and mixing evenly to obtain a preliminary wet mixture; pressing; preparing clinker powder; mixing ultrafine hot-quenched steel slag powder, ultrafine slag powder, the remaining ultrafine desulfurized gypsum powder, and clinker powder, mixing evenly, and sealing for storage to obtain the cementitious material. Through the synergistic effect of hot-quenched steel slag-based multi-solid wastes, the cementitious material is prepared without the use of chemical alkaline activators, achieving effective resource utilization of steel slag, reducing waste, and mitigating carbon emissions and land occupation caused by long-term steel slag accumulation, resulting in significant environmental and social benefits.

Description

Technical Field

[0001] This invention relates to the field of building cementitious technology, specifically to a hot-quenched steel slag-based multi-solid waste synergistic composite cementitious material and its preparation method. Background Technology

[0002] my country's construction industry is booming, and the demand for cement is increasing year by year. Cement production consumes a large amount of raw materials every year, and these raw materials are non-renewable. Ordinary Portland cement is currently the most widely used cementitious material, but it has disadvantages such as high energy consumption during production and environmental pollution.

[0003] Steel slag, a major solid waste from the steel industry, has an annual output exceeding 100 million tons in my country, but its comprehensive utilization rate is less than 30%. Long-term, large-scale accumulation of steel slag causes environmental problems such as land encroachment and heavy metal leaching. Utilizing hot-quenched steel slag to prepare multi-solid-waste synergistic cementitious materials can not only mitigate the environmental pollution caused by steel slag but also reduce the high carbon emissions from cement production.

[0004] Most existing solid waste-based cementitious materials require the addition of chemical reagents and finished cement, which cannot sufficiently reduce costs and environmental pollution. Steel slag has low utilization rate and cannot be consumed in large quantities. Optimization is needed in the proportioning and preparation methods of multi-solid waste synergistic cementitious materials to achieve full recycling and utilization, thereby reducing costs and carbon emissions. Summary of the Invention

[0005] In view of this, the present invention provides a hot-quenched steel slag-based multi-solid waste synergistic composite cementitious material and its preparation method. The main purpose is to increase the consumption of hot-quenched steel slag and various solid wastes, and reduce the carbon dioxide generated during cement firing, so as to reduce the pollution problem caused by long-term accumulation of solid waste to the environment.

[0006] To address the above problems, the present invention mainly provides the following technical solutions:

[0007] On one hand, the present invention provides a method for preparing a hot-quenched steel slag-based multi-solid waste synergistic composite cementitious material, comprising the following steps:

[0008] S1. Preparation of ultrafine powder: The raw materials of the cementitious material are ground and sieved to obtain various ultrafine powders. The raw materials, by weight percentage, include 24-40 wt% hot-quenched steel slag, 20 wt% desulfurized gypsum, 18-40 wt% slag, 9.2-18.4 wt% coal gangue, and 6.8-13.6 wt% carbide slag.

[0009] S2. Preparation of preliminary wet mixture: Mix ultrafine coal gangue powder, ultrafine carbide slag powder and part of ultrafine desulfurization gypsum powder, add water, and mix evenly to obtain preliminary wet mixture;

[0010] S3. Pressing: The preliminary wet mixture is pressed to obtain a cake-shaped mixture;

[0011] S4. Preparation of clinker powder: The cake mixture is sequentially dried, calcined, ground, and sieved to obtain clinker powder;

[0012] S5. Preparation of cementitious material: Mix ultrafine hot-quenched steel slag powder, ultrafine slag powder, remaining ultrafine desulfurized gypsum powder and the clinker powder, stir and mix evenly, seal and store to obtain cementitious material.

[0013] Preferably, in step S1: when grinding each raw material, the grinding time is 40 minutes; and / or

[0014] When screening raw materials, hot-quenched steel slag and blast furnace slag are passed through a 300-mesh square-hole sieve, while desulfurized gypsum, coal gangue, and calcium carbide slag are passed through a 200-mesh square-hole sieve; and / or

[0015] The specific surface area of ​​the ultrafine hot-quenched steel slag powder is 453 m². 2 / kg, the specific surface area of ​​the ultrafine slag powder is 426m². 2 / kg.

[0016] Preferably, in step S2: the amount of ultrafine desulfurized gypsum powder used is 20-40% of the total weight of the ultrafine desulfurized gypsum powder; and / or

[0017] The amount of water used is 15% of the total weight of ultrafine coal gangue powder, ultrafine calcium carbide slag powder, and part of ultrafine desulfurization gypsum powder.

[0018] Preferably, in step S2, the stirring time before and after adding water is 15 minutes.

[0019] Preferably, in step S3: the diameter of the cake mixture is 100 mm and the thickness is 6 mm.

[0020] Preferably, in step S4: when drying the cake mixture, the cake mixture is placed in a forced-air drying oven and dried at 105°C for 24 hours; and / or

[0021] When calcining the cake-shaped mixture, heat it to 900°C at a heating rate of 10°C / min, then heat it to 1250°C at a heating rate of 5°C / min, and calcine at this constant temperature for 30 min; and / or

[0022] When grinding the cake-shaped mixture, the grinding time is 30 minutes; and / or

[0023] When the cake-shaped mixture is screened, it is passed through a 200-mesh square-hole sieve.

[0024] Preferably, in step S4: after calcining the cake mixture, it is quickly taken out and cooled, and then ground.

[0025] Preferably, in step S5, the stirring time is 15 minutes.

[0026] Another aspect of the present invention provides a hot-quenched steel slag-based multi-solid waste synergistic composite cementitious material, said cementitious material being prepared by the above-described preparation method of the hot-quenched steel slag-based multi-solid waste synergistic composite cementitious material.

[0027] Preferably, the initial setting time of the cementitious material is 30 min, the final setting time is 70 min, the 3-day compressive strength is not less than 21.6 MPa, and the 28-day compressive strength is not less than 28.8 MPa.

[0028] Compared with the prior art, the present invention provides a hot-quenched steel slag-based multi-solid waste synergistic composite cementitious material and its preparation method, which have the following beneficial effects:

[0029] On the one hand, this invention provides a method for preparing a hot-quenched steel slag-based multi-solid-waste synergistic composite cementitious material. By using hot-quenched steel slag, a waste product generated during steel smelting, as raw material, it achieves the resource utilization of steel slag tailings, solving to some extent the environmental pollution and resource waste problems caused by long-term steel slag accumulation, and realizing the recycling of steel slag. On the other hand, by using desulfurized gypsum, slag, coal gangue, and carbide slag as raw materials, the synergistic cementitious material system can achieve internal activation, eliminating the need for alkaline activators such as sodium hydroxide, water glass, and potassium hydroxide. This reduces the cost of traditional multi-solid-waste synergistic cementitious materials, simplifies production steps, and realizes the recycling of multiple solid wastes, maximizing the solution to the solid waste accumulation problem. The cementitious material prepared using this method can replace traditional silicate cement, reducing carbon emissions caused by the firing of silicate cement clinker.

[0030] On the other hand, this invention provides a hot-quenched steel slag-based multi-solid-waste synergistic composite cementitious material with an initial setting time of 30 min, a final setting time of 70 min, a 3-day compressive strength of not less than 21.6 MPa, and a 28-day compressive strength of not less than 28.8 MPa. It can rapidly develop strength, with rapid early-stage strength development. Specifically, the interaction between desulfurized gypsum, slag, and hot-quenched steel slag allows the sulfur and calcium in the desulfurized gypsum to react with the calcium aluminum silicate in the slag and the calcium in the hot-quenched steel slag to form calcium vanadate (AFt), providing early-stage strength to the cementitious material. The hot-quenched steel slag... Tricalcium silicate and dicalcium silicate, as well as dicalcium silicate in slag, undergo hydration reactions to generate calcium silicate hydrate (CSH), providing stable mid-to-late-stage strength for cementitious materials. When the cake-shaped mixture made from coal gangue, carbide slag, and desulfurized gypsum is calcined, the alumina and silica in the coal gangue, the calcium in the carbide slag, and the sulfur and calcium in the desulfurized gypsum form tetracalcium sulfoaluminate and dicalcium silicate during high-temperature calcination. These can rapidly hydrate in water to generate calcium vanadate (AFt) and calcium silicate hydrate (CSH), providing early strength for cementitious materials and ensuring the stability of their strength development. Attached Figure Description

[0031] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0032] Figure 1 This is a flowchart illustrating the preparation method of a hot-quenched steel slag-based multi-solid waste synergistic cementitious material according to an embodiment of the present invention.

[0033] Figure 2 This is a diagram illustrating the hot-quenched steel slag-based multi-solid waste synergistic cementitious material prepared according to an embodiment of the present invention. Detailed Implementation

[0034] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0035] To overcome the shortcomings of existing technologies, this invention proposes a hot-quenched steel slag-based multi-solid waste synergistic cementitious material and its preparation method. The design concept of this invention is as follows: Ordinary silicate cement production is energy-intensive and environmentally polluting; large-scale accumulation of steel slag causes land occupation and environmental pollution; solid waste-based cementitious materials require the addition of chemical reagents and finished cement, resulting in high costs and high carbon emissions. This invention utilizes hot-quenched steel slag as a raw material, taking advantage of its certain hydraulic activity, and uses desulfurized gypsum, slag, coal gangue, and carbide slag as raw materials. The synergistic cementitious material system can achieve internal activation without the need for chemical alkaline activators, providing early strength and stable mid-to-late-stage strength to the cementitious material, reducing the cost of traditional multi-solid waste synergistic cementitious materials and simplifying the production process. The resulting cementitious material not only solves the above problems but also rapidly develops strength, with rapid early strength development.

[0036] The specific solution of this invention is as follows:

[0037] On the one hand, such as Figure 1 As shown in the figure, this invention provides a method for preparing a hot-quenched steel slag-based multi-solid waste synergistic cementitious material, comprising the following steps:

[0038] Step S1: Preparation of ultrafine powder: The raw materials of the cementitious material are ground and sieved to obtain various ultrafine powders. The raw materials, by weight percentage, include 24-40 wt% hot quenched steel slag, 20 wt% desulfurized gypsum, 18-40 wt% slag, 9.2-18.4 wt% coal gangue, and 6.8-13.6 wt% carbide slag.

[0039] In this step, the grinding time for each raw material is 40 minutes; during the screening process, hot-quenched steel slag and blast furnace slag are passed through a 300-mesh square-hole sieve, while desulfurized gypsum, coal gangue, and carbide slag are passed through a 200-mesh square-hole sieve; the specific surface area of ​​the ultrafine hot-quenched steel slag powder is 453 m². 2 / kg, the specific surface area of ​​the ultrafine slag powder is 426m². 2 / kg.

[0040] Step S2: Preparation of preliminary wet mixture: Mix ultrafine coal gangue powder, ultrafine carbide slag powder and part of ultrafine desulfurization gypsum powder, add water, and mix evenly to obtain preliminary wet mixture.

[0041] In this step, the amount of ultrafine desulfurized gypsum powder used is 20-40% of the total weight of the ultrafine desulfurized gypsum powder; the amount of water used is 15% of the total weight of ultrafine coal gangue powder, ultrafine carbide slag powder and part of the ultrafine desulfurized gypsum powder; the stirring time before and after adding water is 15 minutes.

[0042] Step S3, pressing: The preliminary wet mixture is pressed to obtain a cake-shaped mixture.

[0043] In this step, the cake mixture has a diameter of 100 mm and a thickness of 6 mm.

[0044] Step S4: Prepare clinker powder: The cake mixture is dried, calcined, ground and sieved in sequence to obtain clinker powder.

[0045] In this step, when drying the cake mixture, it is placed in a forced-air drying oven and dried at 105°C for 24 hours; when calcining the cake mixture, it is heated to 900°C at a heating rate of 10°C / min, then heated to 1250°C at a heating rate of 5°C / min, and calcined at a constant temperature for 30 minutes; when grinding the cake mixture, the grinding time is 30 minutes; when sieving the cake mixture, it is passed through a 200-mesh square-hole sieve.

[0046] Preferably, after calcining the cake-shaped mixture, it is quickly removed, cooled, and then ground.

[0047] When the cake-shaped mixture is calcined, the aluminum and silica in the coal gangue, the calcium in the carbide slag, and the sulfur and calcium in the desulfurized gypsum form tetracalcium sulfoaluminate and dicalcium silicate during the high-temperature calcination process. When they come into contact with water, they can be rapidly hydrated to form calcium vanadate (AFt) and hydrated calcium silicate (CSH), which provide early strength for cementitious materials and ensure the stability of their strength development.

[0048] Step S5: Preparation of cementitious material: Mix ultrafine hot quenched steel slag powder, ultrafine slag powder, remaining ultrafine desulfurized gypsum powder and the clinker powder, stir and mix evenly, seal and store to obtain cementitious material.

[0049] The interaction between desulfurized gypsum, slag, and hot-quenched steel slag is as follows: the sulfur and calcium in the desulfurized gypsum react with the calcium aluminum silicate in the slag and the calcium in the hot-quenched steel slag to form calcium vanadate (AFt), which provides early strength to the cementitious material. The tricalcium silicate and dicalcium silicate in the hot-quenched steel slag and the dicalcium silicate in the slag undergo hydration reactions to form hydrated calcium silicate (CSH), which provides stable mid-to-late-stage strength to the cementitious material.

[0050] In this step, the stirring time is 15 minutes.

[0051] On the other hand, such as Figure 2 As shown, this embodiment of the invention provides a hot-quenched steel slag-based multi-solid waste synergistic composite cementitious material, which is prepared by the above-mentioned preparation method of hot-quenched steel slag-based multi-solid waste synergistic composite cementitious material.

[0052] Preferably, the initial setting time of the cementitious material is 30 min, the final setting time is 70 min, the 3-day compressive strength is not less than 21.6 MPa, and the 28-day compressive strength is not less than 28.8 MPa.

[0053] In summary, this invention utilizes hot-quenched steel slag, a waste product generated during steel smelting, as a raw material, achieving resource utilization of steel slag tailings. This addresses, to some extent, the environmental pollution and resource waste caused by long-term steel slag accumulation, realizing the recycling of steel slag. By using desulfurized gypsum, slag, coal gangue, and calcium carbide slag as raw materials, and employing a synergistic cementitious material system, internal activation can be achieved without the use of alkaline activators such as sodium hydroxide, water glass, and potassium hydroxide. This reduces the cost of traditional multi-solid-waste synergistic cementitious materials, simplifies production steps, and enables the recycling of various solid wastes, maximizing the solution to the solid waste accumulation problem. The cementitious material prepared using this method can replace traditional silicate cement, reducing carbon emissions from the firing of silicate cement clinker.

[0054] The present invention will be further illustrated below with specific embodiments:

[0055] The specific properties of the raw materials used in the following examples are as follows:

[0056] The hot-quenched steel slag was sourced from Ji'an Iron and Steel Co., Ltd.

[0057] The desulfurized gypsum comes from Luetu Fine Chemicals (Hebei) Co., Ltd., and contains 83.46 wt% β-hemihydrate calcium sulfate and soluble anhydrous calcium sulfate.

[0058] The slag comes from Chenxu Minerals and has a density of 2.91 g / cm³. 3 ;

[0059] The coal gangue is sourced from the Jungar mining area in Ordos City, Inner Mongolia Autonomous Region, and originates from Inner Mongolia Jiutai Energy Group. It is used for calcination of the mixed feedstock.

[0060] The calcium carbide slag is the waste residue obtained after the hydrolysis of calcium carbide to obtain acetylene. The calcium carbide slag used in this experiment was produced in Baotou City, Inner Mongolia Autonomous Region, and was used for calcination of the mixture.

[0061] The chemical composition of the raw materials used in the following examples is shown in Table 1.

[0062] Table 1 Chemical composition of raw materials (wt%)

[0063]

[0064] Example 1

[0065] This embodiment provides a method for preparing a hot-quenched steel slag-based multi-solid waste synergistic cementitious material, including the following steps:

[0066] 1) Prepare raw materials with a total weight of 5kg: as shown in Table 2, by weight percentage, hot quenched steel slag 24wt%, and among the solid wastes, desulfurized gypsum 20wt%, slag 40wt%, coal gangue 9.2wt%, and carbide slag 6.8wt%.

[0067] Slag has a specific surface area of ​​426 m². 2 / kg of S95 grade blast furnace slag, desulfurized gypsum, coal gangue and carbide slag are all above 200 mesh.

[0068] 2) Take coal gangue, carbide slag and some desulfurization gypsum and mix them thoroughly. Add 0.15 kg of tap water and stir thoroughly again to obtain a preliminary wet mixture.

[0069] The amount of desulfurized gypsum used is 0.2 kg, accounting for 20% of the total weight of desulfurized gypsum.

[0070] 3) The mixed preliminary wet mixture is pressed into a cake-shaped mixture with a thickness of 6mm and a diameter of 100mm using a cake press.

[0071] 4) Place the cake mixture into a blower dryer and dry at 105℃ for 24 hours.

[0072] 5) Place the dried cake mixture into a high-temperature furnace for calcination, then grind and sieve to obtain cooked powder.

[0073] When calcining the cake mixture, heat it to 900℃ at a heating rate of 10℃ / min, then heat it to 1250℃ at a heating rate of 5℃ / min, and calcine it at a constant temperature for 30 minutes. After calcination, remove it quickly, grind it for 30 minutes, and then pass it through a 200-mesh square hole sieve.

[0074] 6) Use a mixer to thoroughly mix the hot quenched steel slag, blast furnace slag, residual desulfurization gypsum and clinker powder until uniform to obtain a cementitious material.

[0075] Using a water-to-binder ratio of 0.24, add 0.5 wt% polycarboxylate superplasticizer, place in a mixer and mix at low speed for 90 seconds, let stand for 30 seconds, then mix at high speed for 120 seconds, and finally mold and cure.

[0076] As shown in Table 3, the initial setting time of the cementitious material prepared in this embodiment is 30 min, the final setting time is 70 min, the 3-day compressive strength is 21.6 MPa, and the 28-day compressive strength is 28.8 MPa.

[0077] Example 2

[0078] This embodiment provides a method for preparing a hot-quenched steel slag-based multi-solid waste synergistic cementitious material, including the following steps:

[0079] 1) Prepare raw materials with a total weight of 5kg: as shown in Table 2, by weight percentage, hot quenched steel slag 32wt%, and in the solid waste, desulfurized gypsum 20wt%, slag 32wt%, coal gangue 9.2wt%, and carbide slag 6.8wt%.

[0080] Slag has a specific surface area of ​​426 m². 2 / kg of S95 grade blast furnace slag, desulfurized gypsum, coal gangue and carbide slag are all above 200 mesh.

[0081] 2) Take coal gangue, carbide slag and some desulfurization gypsum and mix them thoroughly. Add 0.15 kg of tap water and stir thoroughly again to obtain a preliminary wet mixture.

[0082] The amount of desulfurized gypsum used is 0.2 kg, accounting for 20% of the total weight of desulfurized gypsum.

[0083] 3) The mixed preliminary wet mixture is pressed into a cake-shaped mixture with a thickness of 6mm and a diameter of 100mm using a cake press.

[0084] 4) Place the cake mixture into a blower dryer and dry at 105℃ for 24 hours.

[0085] 5) Place the dried cake mixture into a high-temperature furnace for calcination, then grind and sieve to obtain cooked powder.

[0086] When calcining the cake mixture, heat it to 900℃ at a heating rate of 10℃ / min, then heat it to 1250℃ at a heating rate of 5℃ / min, and calcine it at a constant temperature for 30 minutes. After calcination, remove it quickly, grind it for 30 minutes, and then pass it through a 200-mesh square hole sieve.

[0087] 6) Use a mixer to thoroughly mix the hot quenched steel slag, blast furnace slag, residual desulfurization gypsum and clinker powder until uniform to obtain a cementitious material.

[0088] Using a water-to-binder ratio of 0.24, add 0.5 wt% polycarboxylate superplasticizer, place in a mixer and mix at low speed for 90 seconds, let stand for 30 seconds, then mix at high speed for 120 seconds, and finally mold and cure.

[0089] As shown in Table 3, the initial setting time of the cementitious material prepared in this embodiment is 30 min, the final setting time is 70 min, the 3-day compressive strength is 22.5 MPa, and the 28-day compressive strength is 31.4 MPa.

[0090] Example 3

[0091] This embodiment provides a method for preparing a hot-quenched steel slag-based multi-solid waste synergistic cementitious material, including the following steps:

[0092] 1) Prepare raw materials with a total weight of 5kg: as shown in Table 2, by weight percentage, hot quenched steel slag 40wt%, and in the solid waste, desulfurized gypsum 20wt%, slag 24wt%, coal gangue 9.2wt%, and carbide slag 6.8wt%.

[0093] Slag has a specific surface area of ​​426 m². 2 / kg of S95 grade blast furnace slag, desulfurized gypsum, coal gangue and carbide slag are all above 200 mesh.

[0094] 2) Take coal gangue, carbide slag and some desulfurization gypsum and mix them thoroughly. Add 0.15 kg of tap water and stir thoroughly again to obtain a preliminary wet mixture.

[0095] The amount of desulfurized gypsum used is 0.2 kg, accounting for 20% of the total weight of desulfurized gypsum.

[0096] 3) The mixed preliminary wet mixture is pressed into a cake-shaped mixture with a thickness of 6mm and a diameter of 100mm using a cake press.

[0097] 4) Place the cake mixture into a blower dryer and dry at 105℃ for 24 hours.

[0098] 5) Place the dried cake mixture into a high-temperature furnace for calcination, then grind and sieve to obtain cooked powder.

[0099] When calcining the cake mixture, heat it to 900℃ at a heating rate of 10℃ / min, then heat it to 1250℃ at a heating rate of 5℃ / min, and calcine it at a constant temperature for 30 minutes. After calcination, remove it quickly, grind it for 30 minutes, and then pass it through a 200-mesh square hole sieve.

[0100] 6) Use a mixer to thoroughly mix the hot quenched steel slag, blast furnace slag, residual desulfurization gypsum and clinker powder until uniform to obtain a cementitious material.

[0101] Using a water-to-binder ratio of 0.24, add 0.5 wt% polycarboxylate superplasticizer, place in a mixer and mix at low speed for 90 seconds, let stand for 30 seconds, then mix at high speed for 120 seconds, and finally mold and cure.

[0102] As shown in Table 3, the initial setting time of the cementitious material prepared in this embodiment is 30 min, the final setting time is 70 min, the 3-day compressive strength is 26.3 MPa, and the 28-day compressive strength is 35.1 MPa.

[0103] Example 4

[0104] This embodiment provides a method for preparing a hot-quenched steel slag-based multi-solid waste synergistic cementitious material, including the following steps:

[0105] 1) Prepare raw materials with a total weight of 5kg: as shown in Table 2, by weight percentage, hot quenched steel slag 35wt, and in the solid waste, desulfurized gypsum 20wt%, slag 21wt%, coal gangue 13.8wt%, and carbide slag 10.2wt%.

[0106] Slag has a specific surface area of ​​426 m². 2 / kg of S95 grade blast furnace slag, desulfurized gypsum, coal gangue and carbide slag are all above 200 mesh.

[0107] 2) Take coal gangue, carbide slag and some desulfurization gypsum and mix them thoroughly. Add 0.225 kg of tap water and stir thoroughly again to obtain a preliminary wet mixture.

[0108] The amount of desulfurized gypsum used is 0.3 kg, accounting for 30% of the total weight of desulfurized gypsum.

[0109] 3) The mixed preliminary wet mixture is pressed into a cake-shaped mixture with a thickness of 6mm and a diameter of 100mm using a cake press.

[0110] 4) Place the cake mixture into a blower dryer and dry at 105℃ for 24 hours.

[0111] 5) Place the dried cake mixture into a high-temperature furnace for calcination, then grind and sieve to obtain cooked powder.

[0112] When calcining the cake mixture, heat it to 900℃ at a heating rate of 10℃ / min, then heat it to 1250℃ at a heating rate of 5℃ / min, and calcine it at a constant temperature for 30 minutes. After calcination, remove it quickly, grind it for 30 minutes, and then pass it through a 200-mesh square hole sieve.

[0113] 6) Use a mixer to thoroughly mix the hot quenched steel slag, blast furnace slag, residual desulfurization gypsum and clinker powder until uniform to obtain a cementitious material.

[0114] Using a water-to-binder ratio of 0.24, add 0.5 wt% polycarboxylate superplasticizer, place in a mixer and mix at low speed for 90 seconds, let stand for 30 seconds, then mix at high speed for 120 seconds, and finally mold and cure.

[0115] As shown in Table 3, the initial setting time of the cementitious material prepared in this embodiment is 30 min, the final setting time is 70 min, the 3-day compressive strength is 29.7 MPa, and the 28-day compressive strength is 38.4 MPa.

[0116] Example 5

[0117] This embodiment provides a method for preparing a hot-quenched steel slag-based multi-solid waste synergistic cementitious material, including the following steps:

[0118] 1) Prepare raw materials with a total weight of 5kg: as shown in Table 2, by weight percentage, hot quenched steel slag 30wt%, and in the solid waste, desulfurized gypsum 20wt%, slag 18wt%, coal gangue 18.4wt%, and carbide slag 13.6wt%.

[0119] Slag has a specific surface area of ​​426 m². 2 / kg of S95 grade blast furnace slag, desulfurized gypsum, coal gangue and carbide slag are all above 200 mesh.

[0120] 2) Take coal gangue, carbide slag and some desulfurization gypsum and mix them thoroughly. Add 0.3 kg of tap water and stir thoroughly again to obtain a preliminary wet mixture.

[0121] The amount of desulfurized gypsum used is 0.4 kg, accounting for 40% of the total weight of desulfurized gypsum.

[0122] 3) The mixed preliminary wet mixture is pressed into a cake-shaped mixture with a thickness of 6mm and a diameter of 100mm using a cake press.

[0123] 4) Place the cake mixture into a blower dryer and dry at 105℃ for 24 hours.

[0124] 5) Place the dried cake mixture into a high-temperature furnace for calcination, then grind and sieve to obtain cooked powder.

[0125] When calcining the cake mixture, heat it to 900℃ at a heating rate of 10℃ / min, then heat it to 1250℃ at a heating rate of 5℃ / min, and calcine it at a constant temperature for 30 minutes. After calcination, remove it quickly, grind it for 30 minutes, and then pass it through a 200-mesh square hole sieve.

[0126] 6) Use a mixer to thoroughly mix the hot quenched steel slag, blast furnace slag, residual desulfurization gypsum and clinker powder until uniform to obtain a cementitious material.

[0127] Using a water-to-binder ratio of 0.24, add 0.5 wt% polycarboxylate superplasticizer, place in a mixer and mix at low speed for 90 seconds, let stand for 30 seconds, then mix at high speed for 120 seconds, and finally mold and cure.

[0128] As shown in Table 3, the initial setting time of the cementitious material prepared in this embodiment is 30 min, the final setting time is 70 min, the 3-day compressive strength is 31.2 MPa, and the 28-day compressive strength is 40.5 MPa.

[0129] Comparative Example

[0130] This comparative example provides a method for preparing a hot-quenched steel slag-based multi-solid waste synergistic cementitious material, including the following steps:

[0131] 1) Prepare raw materials with a total weight of 5kg: as shown in Table 2, by weight percentage, hot quenched steel slag 35wt, desulfurized gypsum 20wt, slag 35wt, and calcium aluminate 10wt.

[0132] Slag has a specific surface area of ​​426 m². 2 / kg of S95 grade blast furnace slag, and desulfurized gypsum with a mesh size of 200 or higher.

[0133] 2) Use a mixer to thoroughly mix hot quenched steel slag, slag, desulfurized gypsum, slag and calcium aluminate until uniform to obtain a cementitious material.

[0134] Using a water-to-binder ratio of 0.32, mix at low speed in a mixer for 90 seconds, let stand for 30 seconds, then mix at high speed for 120 seconds, and finally shape and cure.

[0135] As shown in Table 3, the cementitious material prepared in this comparative example had an initial setting time of 40 min, a final setting time of 90 min, a 3-day compressive strength of 6.9 MPa, and a 28-day compressive strength of 22.5 MPa.

[0136] Table 2 Different raw material components of cementitious materials

[0137]

[0138] Table 3 Mechanical properties of cementitious materials with different raw material compositions

[0139]

[0140] Examples 1-3 show a gradient comparison of hot-quenched steel slag and blast furnace slag admixtures. The hot-quenched steel slag synergistically interacts with multiple solid wastes (composed of blast furnace slag and desulfurized gypsum). The sulfur and calcium in the desulfurized gypsum react with the calcium aluminum silicate in the blast furnace slag and the calcium in the hot-quenched steel slag to form calcium vanadate (AFt), providing early strength to the cementitious material. Simultaneously, the blast furnace slag contains a small amount of dicalcium silicate, while the steel slag contains dicalcium silicate and tricalcium silicate, which continuously hydrate to provide strength. Examples 3-5 show clinker powder prepared from coal gangue, carbide slag, and desulfurized gypsum, and then admixed with... A gradient comparison was made, showing that the alumina and silica in coal gangue, the calcium in carbide slag, and the sulfur and calcium in desulfurized gypsum form tetracalcium sulfoaluminate and dicalcium silicate during high-temperature calcination. These substances can rapidly hydrate in water to form calcium vanadate (AFt) and calcium silicate hydrate (CSH), providing early strength to the cementitious material and ensuring its strength development stability. In the comparative example, calcium aluminate was added directly without preparing clinker powder, resulting in cementitious materials with lower early and mid-to-late-stage strengths, especially a 3-day compressive strength of only 6.9 MPa. In the embodiments of this invention, the cementitious material prepared from hot-quenched steel slag, blast furnace slag, desulfurized gypsum, and clinker powder showed a significant improvement in early strength, with a 3-day compressive strength of not less than 21.6 MPa.

[0141] Furthermore, the tricalcium silicate and dicalcium silicate in the hot-quenched steel slag and the dicalcium silicate in the slag undergo a hydration reaction to generate calcium silicate hydrate (CSH), which provides stable mid-to-late stage strength for cementitious materials, and also improves their final strength to a certain extent, with a 28-day compressive strength of not less than 28.8 MPa.

[0142] In summary, the embodiments of the present invention, through the synergistic effect of hot-quenched steel slag and multiple solid wastes, and by controlling the content of hot-quenched steel slag and multiple solid wastes, improve the early compressive strength of cementitious materials, and also enhance the compressive strength in the middle and later stages. The 3-day compressive strength is not less than 21.6 MPa, and the 28-day compressive strength is not less than 28.8 MPa. This achieves effective resource utilization of steel slag, reduces waste, and lowers the carbon emissions and land occupation problems caused by long-term accumulation of steel slag, resulting in significant environmental and social benefits.

[0143] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for preparing a hot-quenched steel slag-based multi-solid waste synergistic composite cementitious material, characterized in that, Includes the following steps: S1. Preparation of ultrafine powder: The raw materials of the cementitious material are ground and sieved to obtain various ultrafine powders. The raw materials, by weight percentage, include 24-40 wt% hot-quenched steel slag, 20 wt% desulfurized gypsum, 18-40 wt% slag, 9.2-18.4 wt% coal gangue, and 6.8-13.6 wt% carbide slag. S2. Preparation of preliminary wet mixture: Mix ultrafine coal gangue powder, ultrafine carbide slag powder and part of ultrafine desulfurization gypsum powder, add water, and mix evenly to obtain preliminary wet mixture; S3. Pressing: The preliminary wet mixture is pressed to obtain a cake-shaped mixture; S4. Preparation of clinker powder: The cake mixture is sequentially dried, calcined, ground, and sieved to obtain clinker powder; S5. Preparation of cementitious material: Mix ultrafine hot-quenched steel slag powder, ultrafine slag powder, remaining ultrafine desulfurized gypsum powder and the clinker powder, stir and mix evenly, seal and store to obtain cementitious material. In step S1: When screening raw materials, hot-quenched steel slag and blast furnace slag are passed through a 300-mesh square-hole sieve, while desulfurized gypsum, coal gangue, and calcium carbide slag are passed through a 200-mesh square-hole sieve; and / or The specific surface area of ​​the ultrafine hot-quenched steel slag powder is 453 m². 2 / kg, the specific surface area of ​​the ultrafine slag powder is 426m². 2 / kg.

2. The preparation method of the hot-quenched steel slag-based multi-solid waste synergistic composite cementitious material according to claim 1, characterized in that, In step S1: When grinding each raw material, the grinding time is 40 minutes.

3. The preparation method of the hot-quenched steel slag-based multi-solid waste synergistic composite cementitious material according to claim 1, characterized in that, In step S2: The amount of the ultrafine desulfurized gypsum powder used is 20-40% of the total weight of the ultrafine desulfurized gypsum powder; and / or The amount of water used is 15% of the total weight of ultrafine coal gangue powder, ultrafine calcium carbide slag powder, and part of ultrafine desulfurization gypsum powder.

4. The preparation method of the hot-quenched steel slag-based multi-solid waste synergistic composite cementitious material according to claim 1, characterized in that, In step S2: The stirring time before and after adding water is 15 minutes.

5. The preparation method of the hot-quenched steel slag-based multi-solid waste synergistic composite cementitious material according to claim 1, characterized in that, In step S3: The cake-shaped mixture has a diameter of 100 mm and a thickness of 6 mm.

6. The preparation method of the hot-quenched steel slag-based multi-solid waste synergistic composite cementitious material according to claim 1, characterized in that, In step S4: When drying the cake-shaped mixture, the cake-shaped mixture is placed in a forced-air drying oven and dried at 105°C for 24 hours; and / or When calcining the cake-shaped mixture, heat it to 900°C at a heating rate of 10°C / min, then heat it to 1250°C at a heating rate of 5°C / min, and calcine at this constant temperature for 30 min; and / or When grinding the cake-shaped mixture, the grinding time is 30 minutes; and / or When the cake-shaped mixture is screened, it is passed through a 200-mesh square-hole sieve.

7. The preparation method of the hot-quenched steel slag-based multi-solid waste synergistic composite cementitious material according to claim 1 or 6, characterized in that, In step S4: After calcining the cake-shaped mixture, it is quickly removed, cooled, and then ground.

8. The preparation method of the hot-quenched steel slag-based multi-solid waste synergistic composite cementitious material according to claim 1, characterized in that, In step S5: The stirring time is 15 minutes.

9. A hot-quenched steel slag-based multi-solid waste synergistic composite cementitious material, characterized in that, The cementitious material is prepared by the preparation method of the hot-quenched steel slag-based multi-solid waste synergistic composite cementitious material according to any one of claims 1-8.

10. The hot-quenched steel slag-based multi-solid-waste synergistic composite cementitious material according to claim 9, characterized in that, The initial setting time of the cementitious material is 30 min, the final setting time is 70 min, the 3-day compressive strength is not less than 21.6 MPa, and the 28-day compressive strength is not less than 28.8 MPa.

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