Multi-source solid waste-based cementing material and preparation method thereof

Abstract

The invention discloses a multi-source solid waste-based cementing material and a preparation method thereof, and relates to the technical field of solidified organic matter soft soil cementing materials. The cementing material is prepared from the following raw materials: carbide slag, desulfurized fly ash, yellow phosphorus slag, high-activity and high-stability steel slag, modified red mud, alkaline residues, desulfurized gypsum, mineral slag and calcium sulphoaluminate; the high-activity and high-stability steel slag is prepared by carrying out steel slag preliminary stabilization treatment and steel slag excitation activation on liquid steel slag; exciting and activating the steel slag: preparing high-activity and high-stability steel slag from the stabilized steel slag, the modified ettringite particles, aluminum sulfate, a polycarboxylate superplasticizer, hexadecyl triethyl ammonium bromide and potassium hydroxide; the modified red mud is prepared from red mud, magnesium hydroxide, N-methyldiethanolamine, desulfurized fly ash, calcium oxide and a ferric chloride solution; the modified ettringite particles are prepared from polyvinyl alcohol and N-beta-aminoethyl-gamma-aminopropyl trimethoxy silane as a modifying agent. The preparation method comprises the following steps: preparing the modified ettringite particles; according to the multi-source solid waste-based cementing material, the compressive strength and the water stability coefficient of the solidified organic matter soft soil are effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of cementitious materials for solidifying organic soft soil, and in particular to a multi-source solid waste-based cementitious material and a preparation method thereof. Background Art

[0002] Organic soft soils have the characteristics of "three highs and three lows": high natural water content, high natural porosity, high compressibility, low strength, low permeability, and a low consolidation coefficient. These characteristics often significantly impact engineering construction. The impact of organic matter on soil properties has become a key research topic in fields such as pedology, geotechnical engineering, civil engineering, and environmental science.

[0003] With the continuous expansion of the expressway network, areas covered by organic soft soil are increasing. Organic soft soil areas have complex engineering geological characteristics and are significantly affected by hydrological, temperature, and climate changes. Under the long-term coupled effects of traffic loads and complex environments, organic soft soil often exhibits strength loss and excessive settlement, seriously impacting road stability and service life. However, traditional soft soil foundation treatment methods cannot effectively meet the technical challenges of long-term service, particularly in terms of bearing capacity, settlement control, and durability. Furthermore, the soil abandonment and replacement processes involved in traditional methods are not only costly but also inconsistent with current engineering concepts of green environmental protection and sustainable development. Therefore, to reduce the occupation of arable land and improve road construction efficiency, solidified organic soft soil roadbed design has gradually become an effective way to overcome land resource constraints and improve road construction efficiency and safety. Solidified organic soft soil refers to the addition of chemical curing agents to natural organic soft soil to improve its structural properties to meet engineering or environmental management requirements. This treatment method can improve the strength, water resistance, durability and impermeability of organic soft soil, making it suitable for use as a structural material.

[0004] In recent years, research on the use of industrial solid waste in the preparation of cementitious materials has become increasingly in-depth, with the main directions including use as auxiliary cementitious materials, preparation of cement clinker, and preparation of composite cementitious materials. Steel slag is a major solid waste generated in the steelmaking process, and its emissions account for approximately 12% to 20% of crude steel production. Due to problems such as poor volume stability, low gelling activity, and high energy consumption for processing, its comprehensive utilization rate is low. Red mud is an industrial waste residue generated in the production of alumina. It has low gelling activity and the risk of releasing heavy metals, and generally cannot be used directly in cementitious materials. The preparation of industrial solid waste into cementitious materials for solidifying organic soils can not only consume a large amount of solid waste materials, but also reduce the demand for raw materials such as cement and lime in engineering construction, greatly reducing engineering costs and carbon emissions, and has important social and economic benefits.

[0005] Publication No. CN114133151A discloses a low-carbon cementitious material mixed with steel slag for solidifying soft soil. The material comprises water glass and dry materials, wherein the dry materials include slag, quicklime, sodium carbonate, and steel slag. The steel slag contains free MgO and CaO, which significantly expand the soil and improve the compactness and strength of the solidified soil (soft soil + low-carbon cementitious material mixed with steel slag + water). However, excessive free MgO and CaO content can degrade the stability of the steel slag, resulting in high volume expansion and cracking of the resulting solidified soil. Publication No. CN119038942A discloses a method for preparing superfluidized solidified soil using a low-dosage inorganic gelling material. The inorganic gelling material, in weight fractions, includes 20-40 parts slag powder, 50-80 parts cement clinker, 6-30 parts gypsum powder, 3-20 parts quicklime, 0.5-2 parts defoamer, 8-15 parts stone powder, and 2-10 parts adsorbent. Mud and the inorganic gelling material are then stirred and mixed to form the superfluidized solidified soil. This technical solution improves the viscosity and strength of the fluidized solidified soil, but does not address the high mass loss rate.

[0006] The cementitious materials used for soil solidification in the existing technology have the following technical problems: the prepared solidified soil has a high volume expansion value and mass loss rate, a low water stability coefficient, and there is a risk of heavy metal leaching. Summary of the Invention

[0007] In order to solve the above-mentioned problems existing in the prior art, the present invention provides a multi-source solid waste-based cementitious material and a preparation method thereof, and achieves the following invention objectives: effectively improving the compressive strength and water stability coefficient of organic soft soil solidified by multi-source solid waste-based cementitious material, and reducing the leaching concentration of heavy metals.

[0008] In order to achieve the above-mentioned purpose of the invention, the technical solutions adopted are as follows: A multi-source solid waste-based cementitious material, the raw materials of which include: carbide slag, desulfurization ash, yellow phosphorus slag, high-activity and high-stability steel slag, modified red mud, alkali slag, desulfurization gypsum, slag, and calcium sulfoaluminate.

[0009] The high-activity and high-stability steel slag is prepared by subjecting liquid steel slag to a preliminary stabilization treatment and steel slag excitation and activation. The steel slag excitation and activation is prepared by using the stabilized steel slag, modified ettringite particles, aluminum sulfate, polycarboxylate water reducer, hexadecyltriethylammonium bromide, and potassium hydroxide to prepare the high-activity and high-stability steel slag.

[0010] The modified red mud is prepared from red mud, magnesium hydroxide, N-methyldiethanolamine, desulfurization ash, calcium oxide and ferric chloride solution.

[0011] The modified ettringite particles adopt polyvinyl alcohol and N-β-aminoethyl-γ-aminopropyltrimethoxysilane as modifiers.

[0012] The mass ratio of the stabilized steel slag, modified ettringite particles, aluminum sulfate, polycarboxylate water reducer, hexadecyltriethylammonium bromide, and potassium hydroxide is (90-100): (8-15): (10-17): (6-9): (4-8): (10-15).

[0013] The mass ratio of the raw materials of the modified red mud, red mud, magnesium hydroxide, N-methyldiethanolamine, desulfurization ash, calcium oxide, and ferric chloride solution is (20-34): (3-7): (5-9): (2-5): (1-4): (17-22); the concentration of the ferric chloride solution is 10 wt%.

[0014] A method for preparing a multi-source solid waste-based cementitious material comprises the steps of preparing modified ettringite particles, preliminary stabilization treatment of steel slag, excitation and activation of steel slag, preparing modified red mud, and compounding the multi-source solid waste cementitious material.

[0015] The modified ettringite particles are prepared as follows: aluminum sulfate is dissolved in deionized water to form an aluminum sulfate solution, desulfurized gypsum and calcium hydroxide are added to the aluminum sulfate solution, and stirred to obtain a suspension; the mass ratio of desulfurized gypsum, calcium hydroxide, aluminum sulfate, and deionized water is (12-18):(1.5-4):(3-7):(50-63); the suspension is added to an autoclave and pressurized, stirring is started, and the temperature is raised at a stirring rate of 200 r / min to 170-190°C, and the temperature is maintained at this temperature and pressure for 3-5 hours. Polyvinyl alcohol and N-β-aminoethyl-γ-aminopropyltrimethoxysilane are added to the reaction solution, with the amount of polyvinyl alcohol added being 4-10% of the mass of the reaction solution, and the amount of N-β-aminoethyl-γ-aminopropyltrimethoxysilane added being 5-8% of the mass of the reaction solution; and ultrasonic treatment is performed for 2-4 hours to obtain the modified ettringite particles.

[0016] The pressurization is performed by filling nitrogen into the high-pressure reactor to control the pressure in the reactor to be 5.96~6 MPa.

[0017] The ultrasonic treatment: the ultrasonic frequency is 34 kHz, and the ultrasonic treatment time is 2 to 4 hours.

[0018] The initial stabilization treatment for steel slag involves pouring liquid steel slag into a slag stewing tank. Water is added from the bottom until the slag is submerged. After soaking for one hour, the water is removed. The slag is then stewed for four to five hours at a temperature of 300-350°C to pulverize the slag. The pulverized slag is then screened and magnetically separated before being microwaved at a frequency of 2.4-2.5 GHz for 15-30 minutes. After microwave treatment, stabilized steel slag is obtained.

[0019] The steel slag activation process involves mixing stabilized steel slag with modified ettringite particles, adding the mixture to a grinding mill, and grinding for 20-30 minutes. Aluminum sulfate, a polycarboxylate water reducer, hexadecyltriethylammonium bromide, and potassium hydroxide are then added to the grinding mill and grinding continues for 10-20 minutes. The grinding process completes to produce highly active and stable steel slag. The mass ratio of stabilized steel slag, modified ettringite particles, aluminum sulfate, polycarboxylate water reducer, hexadecyltriethylammonium bromide, and potassium hydroxide is (90-100):(8-15):(10-17):(6-9):(4-8):(10-15). The grinding mill is equipped with a high-efficiency eddy current classifier, operating at a grinding pressure of 8-10 MPa and an inlet air temperature of 200°C. The ground material is classified by the classifier, and the coarse particles are returned to the grinding area for cyclic grinding.

[0020] The high-activity and high-stability steel slag has a specific surface area of ​​433-526 m² / kg and an average particle size d 50 It is 17.3~28.6μm.

[0021] The modified red mud is prepared by adding red mud, magnesium hydroxide, calcium oxide, and desulfurization ash into deionized water, stirring evenly to form a mixed slurry A, dropping N-methyldiethanolamine into the mixed slurry A, introducing CO2 gas, and adjusting the pH value of the mixed slurry A to 9-10; subjecting the mixed slurry A to microwave treatment; after the microwave treatment is completed, adding ferric chloride solution to the mixed slurry A, reacting for 15-25 minutes, to obtain a mixed slurry B; centrifuging the mixed slurry B and retaining the solid, and vacuum drying and crushing the obtained solid to obtain the modified red mud.

[0022] The microwave treatment: the microwave frequency is 2.4-2.5 GHz, and the microwave treatment time is 15-25 minutes; The modified red mud is prepared by using trivalent metal ions such as Fe³⁺ and Al³⁺ contained in the red mud and divalent metal ions Mg²⁺ to rapidly generate Mg-Fe-Al double hydroxide layered structure (LDH) in situ through microwave field assistance. The reaction principle is: Fe³⁺ + Al³⁺ + Mg²⁺ + OH⁻ + CO3²⁻ + H2O [Mg4AlFe3(OH) 12 ] CO3・3H2O; Mg-Fe-Al LDH can combine with heavy metal ions Pb²⁺ and CrO4²⁻ to form stable [Mg-Al-Fe-Pb] LDH and [Mg-Al-Fe-Cr] LDH.

[0023] The multi-source solid waste composite cementitious material is prepared by first adding carbide slag, desulfurization ash, and yellow phosphorus slag into a drum mixer and stirring at room temperature, spraying deionized water at the same time, stirring and reacting for 40 to 60 minutes, and then standing and aging for 6 to 12 hours after the stirring is completed; the mass ratio of carbide slag, desulfurization ash, yellow phosphorus slag, and deionized water used is (3 to 7): (10 to 15): (12 to 18): (30 to 40). The aged material is dried and crushed into particles with a particle size of ≤1 mm to obtain premix A; premix A, high-activity and high-stability steel slag, modified red mud, alkali residue, desulfurized gypsum, slag, and calcium sulfoaluminate are added to a high-speed grinder and ground for 20-30 minutes to obtain a multi-source solid waste-based cementitious material; the mass ratio of premix A, high-activity and high-stability steel slag, modified red mud, alkali residue, desulfurized gypsum, slag, and calcium sulfoaluminate used is (23-35):(55-66):(20-26):(7-11):(8-16):(17-25):(21-28).

[0024] The beneficial effects of the present invention are as follows: Solidified organic soft soil prepared using the multi-source solid waste-based cementitious material provided by the present invention exhibits an unconfined compressive strength of 1.52 to 1.66 MPa, a water stability coefficient of 88.7 to 91.1%, a pH of 9.0 to 9.8, and a lead leaching concentration of 0.004 to 0.006 mg / L. Compared to cement-solidified organic soft soil, the solidified soil of the present invention exhibits significantly improved unconfined compressive strength and water stability coefficient, reduced mass loss rate, and lower pH and lead leaching concentration, demonstrating the improved performance, durability, safety, and environmental friendliness of the multi-source solid waste-based cementitious material provided by the present invention. DETAILED DESCRIPTION

[0025] The liquid steel slag used in each embodiment of the present invention comprises: CaO 31.6%, Fe2O3 28.5%, SiO2 16.8%, Al2O3 8.7%, and MgO 6.9%. It is in liquid form and has a temperature of 1600-1650°C. The desulfurization gypsum comprises: CaO 46.3%, SiO2 1.8%, Al2O3 0.7%, MgO 0.4%, Fe2O3 0.1%, SO3 50.6%, TiO2 0.02%, and K2O 0.4%. The particle size characteristic value d of the desulfurization gypsum is d 50 The desulfurization ash composition includes: SiO2 48.9%, Al2O3 35.7%, Fe2O35.9%, CaO 4.4%, K2O 1.1%, SO3 1.0%, TiO2 1.0%, MgO 0.8%; the particle size characteristic value d 50The slag composition includes: CaO 45.4%, SiO2 26.3%, Al2O3 12.8%, MgO 7.3%, SO3 1.5%, TiO2 0.6%, K2O 0.4%, Fe2O3 0.4%, MnO 0.3%; the characteristic value of the slag particle size d 50 The composition of carbide slag includes: Ca(OH)2 88.6%, SiO2 4.7%, Al2O3 1.5%, MgO 0.2%, Fe2O3 0.4%, SO3 0.7%, MnO 0.1%; the particle size characteristic value of carbide slag d 50 The yellow phosphorus slag composition includes SiO2 50.2%, CaO 41.7%, Al2O3 3.6%, Fe2O31.5%, P2O5 0.7%, MgO 0.6%, CaF2 0.4%; the particle size characteristic value d of yellow phosphorus slag is 48.3μm. 50 The red mud composition is 37.6 μm. The red mud consists of 41.4% CaO, 24.7% SiO₂, 19.2% Fe₂O₃, 9.8% Al₂O₃, 2.3% Na₂O, and 2.0% TiO₂. Polyvinyl alcohol has a degree of hydrolysis (DH) of 88 mol% and a degree of polymerization (DP) of 500.

[0026] To make the purpose, technical solutions and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention and are not intended to limit the present invention.

[0027] Example 1: A method for preparing a multi-source solid waste-based cementitious material The following steps are involved: Step 1: Preparation of modified ettringite particles 1. Dissolve aluminum sulfate in deionized water and stir at room temperature for 30 minutes until it is completely dissolved to form an aluminum sulfate solution; add desulfurized gypsum to the aluminum sulfate solution, then add calcium hydroxide, and stir evenly to obtain a suspension; the mass ratio of desulfurized gypsum, calcium hydroxide, aluminum sulfate, and deionized water is 16:1.5:7:60.

[0028] 2. Add the suspension to the autoclave and pressurize it with nitrogen. Stop adding nitrogen when the pressure in the autoclave reaches 6.0 MPa. Start stirring and start heating at a stirring rate of 200 r / min. Raise the temperature to 180°C and stop heating. Maintain the temperature and pressure for 3 hours. At this time, the pressure is 10.8 MPa. After the 3-hour heat and pressure maintenance, cool the autoclave at a rate of 10°C / min. After the temperature in the autoclave drops to room temperature, release the nitrogen and remove the reaction liquid from the autoclave for later use.

[0029] 3. Add polyvinyl alcohol and N-β-aminoethyl-γ-aminopropyltrimethoxysilane to the reaction solution and ultrasonicate at 95°C for 2 hours. After the ultrasonication, filter the reaction solution and retain the solid, which is then dried and crushed to obtain modified ettringite particles. The amount of polyvinyl alcohol added is 6% by weight of the reaction solution, and the amount of N-β-aminoethyl-γ-aminopropyltrimethoxysilane added is 8% by weight of the reaction solution. The ultrasonication frequency is 34 kHz.

[0030] The obtained modified ettringite particles, d 50 =122nm; the surface hydroxyl density was measured by Boehm titration and was 4.7mmol / g.

[0031] Step 2: Initial stabilization of slag 1. Pour the liquid slag into the slag stewing tank, add water from the bottom until the slag is submerged, drain the water after soaking for 1 hour, and continue stewing at 300℃ for 5 hours to pulverize the slag. After the stewing is completed, dig out the pulverized slag from the slag stewing tank and set aside.

[0032] 2. First, the pulverized steel slag is passed through a 5mm sieve to remove coarse particles and impurities, and then the metallic iron is separated by magnetic separation using a high-gradient magnetic separator with a magnetic field intensity of 1.2T and a separation speed of 1m / min. The steel slag after magnetic separation is subjected to microwave treatment with a controlled microwave frequency of 2.4GHz, a temperature of 600°C, and a treatment time of 15min. After the microwave treatment, the stabilized steel slag is obtained.

[0033] Step 3: Activation of slag Stabilized steel slag and modified ettringite particles were first added to a grinder and ground for 20 minutes. Aluminum sulfate, polycarboxylate superplasticizer, cetyltriethylammonium bromide, and potassium hydroxide were then added and ground for another 20 minutes. Highly active and stable steel slag was obtained after grinding. The mass ratio of stabilized steel slag, modified ettringite particles, aluminum sulfate, polycarboxylate superplasticizer, cetyltriethylammonium bromide, and potassium hydroxide was 90:8:10:6:8:15.

[0034] The specific surface area of ​​the obtained high-activity and high-stability steel slag is 433m² / kg, and the particle size characteristic value d 50 It is 28.6μm.

[0035] Step 4: Preparation of modified red mud Red mud, magnesium hydroxide, desulfurization ash, and calcium oxide were added to deionized water and stirred at a stirring rate of 300 r / min to form a mixed slurry A. N-methyldiethanolamine was added dropwise to the mixed slurry A. After the addition was complete, CO2 gas was introduced into the mixed slurry A to adjust the pH to 10. The mixed slurry A was then transferred to a microwave reactor. The amount of deionized water added was three times the mass of the red mud.

[0036] After the mixed slurry A was transferred to a microwave reactor, the microwave frequency was set to 2.4 GHz, and the mixed slurry A was subjected to microwave treatment for 25 minutes. After the microwave treatment was completed, a 10 wt % ferric chloride solution was added to the mixed slurry A, and the reaction was continued with stirring for 15 minutes to obtain a mixed slurry B.

[0037] The mixed slurry B was centrifuged at a speed of 1200 r / min for 20 minutes to retain the solid. The obtained solid was vacuum dried at 60° C. for 6 hours. The dried solid was crushed into particles with a particle size of ≤75 μm to obtain modified red mud.

[0038] The mass ratio of red mud, magnesium hydroxide, N-methyldiethanolamine, desulfurization ash, calcium oxide and ferric chloride solution used in this step is 30:5:5:3:4:20.

[0039] Step 5: Compounding cementitious materials from multiple sources of solid waste 1. First, add carbide slag, desulfurization ash, and yellow phosphorus slag into a drum mixer and stir at room temperature while spraying deionized water. Stir and react for 60 minutes. After stirring, let it stand and age for 12 hours. Dry the aged materials and crush them into particles with a particle size of ≤1mm to obtain premix A. The mass ratio of carbide slag, desulfurization ash, yellow phosphorus slag, and deionized water used is 7:10:12:30.

[0040] 2. Add premix A, high-activity and high-stability steel slag, modified red mud, alkali residue, desulfurization gypsum, slag, and calcium sulfoaluminate into a high-speed grinder and grind for 30 minutes to obtain a multi-source solid waste-based cementitious material; the mass ratio of premix A, high-activity and high-stability steel slag, modified red mud, alkali residue, desulfurization gypsum, slag, and calcium sulfoaluminate used is 23:66:26:7:10:17:26.

[0041] Example 2: A method for preparing a multi-source solid waste-based cementitious material The following steps are involved: Step 1: Preparation of modified ettringite particles 1. Dissolve aluminum sulfate in deionized water and stir at room temperature for 30 minutes until it is completely dissolved to form an aluminum sulfate solution; add desulfurized gypsum to the aluminum sulfate solution, then add calcium hydroxide, and stir evenly to obtain a suspension; the mass ratio of desulfurized gypsum, calcium hydroxide, aluminum sulfate, and deionized water is 12:3:5:63.

[0042] 2. Add the suspension to the autoclave and pressurize it with nitrogen. Stop adding nitrogen when the pressure in the autoclave reaches 5.98 MPa. Start stirring and begin heating at a stirring rate of 200 r / min. Raise the temperature to 190°C and then stop heating. Maintain the temperature and pressure for 3 hours, at which point the pressure is 11.7 MPa. After the 3-hour temperature maintenance, cool the autoclave at a rate of 5°C / min. After the autoclave temperature drops to room temperature, release the nitrogen and remove the reaction liquid from the autoclave for later use.

[0043] 3. Add polyvinyl alcohol and N-β-aminoethyl-γ-aminopropyltrimethoxysilane to the reaction solution and ultrasonicate at 95°C for 3 hours. After the ultrasonication, filter the reaction solution and retain the solid, which is then dried and crushed to obtain modified ettringite particles. The amount of polyvinyl alcohol added is 4% by weight of the reaction solution, and the amount of N-β-aminoethyl-γ-aminopropyltrimethoxysilane added is 8% by weight of the reaction solution. The ultrasonication frequency is 34 kHz.

[0044] The obtained modified ettringite particles, d 50 =106nm; the surface hydroxyl density was measured by Boehm titration method and was 4.5mmol / g.

[0045] Step 2: Initial stabilization of slag 1. Pour the liquid slag into the slag stewing pool, add water from the bottom until the slag is submerged, release the water after soaking for 1 hour, control the temperature at 350℃ and continue to stew for 4 hours to pulverize the slag; after the stewing is completed, dig out the pulverized slag in the slag stewing pool and set aside.

[0046] 2. The pulverized steel slag was first passed through a 5 mm sieve to remove coarse particles and impurities. The metallic iron was then separated using a high gradient magnetic separator with a magnetic field strength of 1.2 T and a separation speed of 1 m / min. The magnetically separated steel slag was then microwave treated at a controlled microwave frequency of 2.5 GHz, a temperature of 600°C, and a treatment time of 30 minutes. After the microwave treatment, the stabilized steel slag was obtained.

[0047] Step 3: Activation of slag Stabilized steel slag and modified ettringite particles were first added to a grinder and ground for 30 minutes. Aluminum sulfate, polycarboxylate superplasticizer, cetyltriethylammonium bromide, and potassium hydroxide were then added and ground for another 10 minutes. Highly active and stable steel slag was obtained after grinding. The mass ratio of stabilized steel slag, modified ettringite particles, aluminum sulfate, polycarboxylate superplasticizer, cetyltriethylammonium bromide, and potassium hydroxide was 100:15:15:6:4:15.

[0048] The specific surface area of ​​the obtained high-activity and high-stability steel slag is 480m² / kg, and the particle size characteristic value d 50 It is 17.3μm.

[0049] Step 4: Preparation of modified red mud Red mud, magnesium hydroxide, desulfurization ash, and calcium oxide were added to deionized water and stirred at a stirring rate of 300 r / min to form a mixed slurry A. N-methyldiethanolamine was added dropwise to the mixed slurry A. After the addition was complete, CO2 gas was introduced into the mixed slurry A to adjust the pH to 9. The mixed slurry A was then transferred to a microwave reactor. The amount of deionized water added was 4 times the mass of the red mud.

[0050] After the mixed slurry A was transferred to a microwave reactor, the microwave frequency was set to 2.4 GHz, and the mixed slurry A was subjected to microwave treatment for 25 minutes. After the microwave treatment was completed, a 10 wt % ferric chloride solution was added to the mixed slurry A, and the reaction was continued with stirring for 15 minutes to obtain a mixed slurry B.

[0051] The mixed slurry B was centrifuged at a speed of 1200 r / min for 20 minutes to retain the solid. The obtained solid was vacuum dried at 60° C. for 6 hours. The dried solid was crushed into particles with a particle size of ≤75 μm to obtain modified red mud.

[0052] The mass ratio of red mud, magnesium hydroxide, N-methyldiethanolamine, desulfurization ash, calcium oxide, and ferric chloride solution used in this step is 20:3:9:2:1:17, wherein the concentration of the ferric chloride solution is 10 wt%.

[0053] Step 5: Compounding cementitious materials from multiple sources of solid waste 1. First, add carbide slag, desulfurization ash, and yellow phosphorus slag into a drum mixer and stir at room temperature while spraying deionized water. Stir and react for 60 minutes. After stirring, let it stand and age for 12 hours. Dry the aged materials and crush them into particles with a particle size of ≤1mm to obtain premix A. The mass ratio of carbide slag, desulfurization ash, yellow phosphorus slag, and deionized water used is 4:15:18:30.

[0054] 2. Add premix A, high-activity and high-stability steel slag, modified red mud, alkali residue, desulfurization gypsum, slag, and calcium sulfoaluminate into a high-speed grinder and grind for 30 minutes to obtain a multi-source solid waste-based cementitious material; the mass ratio of premix A, high-activity and high-stability steel slag, modified red mud, alkali residue, desulfurization gypsum, slag, and calcium sulfoaluminate used is 30:60:20:7:8:25:21.

[0055] Example 3: A method for preparing a multi-source solid waste-based cementitious material The following steps are involved: Step 1: Preparation of modified ettringite particles 1. Dissolve aluminum sulfate in deionized water and stir at room temperature for 30 minutes until it is completely dissolved to form an aluminum sulfate solution; add desulfurized gypsum to the aluminum sulfate solution, then add calcium hydroxide, and stir evenly to obtain a suspension; the mass ratio of desulfurized gypsum, calcium hydroxide, aluminum sulfate, and deionized water is 18:4:3:60.

[0056] 2. Add the suspension to the autoclave and pressurize it with nitrogen. Stop adding nitrogen when the pressure in the autoclave reaches 5.96 MPa. Start stirring and start heating at a stirring rate of 200 r / min. Raise the temperature to 170°C and stop heating. Maintain the temperature and pressure for 5 hours. At this time, the pressure is 9.5 MPa. After the 5-hour heat and pressure maintenance, cool the autoclave at a rate of 10°C / min. After the temperature in the autoclave drops to room temperature, release the nitrogen and remove the reaction liquid from the autoclave for later use.

[0057] 3. Add polyvinyl alcohol and N-β-aminoethyl-γ-aminopropyltrimethoxysilane to the reaction solution and ultrasonicate at 95°C for 4 hours. After the ultrasonication, filter the reaction solution and retain the solid, which is then dried and crushed to obtain modified ettringite particles. The amount of polyvinyl alcohol added is 10% by weight of the reaction solution, and the amount of N-β-aminoethyl-γ-aminopropyltrimethoxysilane added is 5% by weight of the reaction solution. The ultrasonication frequency is 34 kHz.

[0058] The obtained modified ettringite particles, d 50 =132nm; the surface hydroxyl density was measured by Boehm titration and was 5.6mmol / g.

[0059] Step 2: Initial stabilization of slag 1. Pour the liquid slag into the slag stewing tank, add water from the bottom until the slag is submerged, drain the water after soaking for 1 hour, control the temperature at 350℃ and continue to stew for 4 hours to pulverize the slag. After the stewing is completed, dig out the pulverized slag from the stewing tank and set aside.

[0060] 2. First, the pulverized steel slag is passed through a 5mm sieve to remove coarse particles and impurities. Then, the metallic iron is separated by magnetic separation using a high-gradient magnetic separator with a magnetic field strength of 1.2T and a separation speed of 1m / min. The magnetically separated steel slag is subjected to microwave treatment with a controlled microwave frequency of 2.5GHz, a temperature of 700°C, and a treatment time of 15min. After the microwave treatment, the stabilized steel slag is obtained.

[0061] Step 3: Activation of slag First, stabilized steel slag and modified ettringite particles were added to a grinder and ground for 20 minutes. Aluminum sulfate, polycarboxylate superplasticizer, cetyltriethylammonium bromide, and potassium hydroxide were then added and ground for another 10 minutes. Highly active and stable steel slag was obtained after grinding. The mass ratio of stabilized steel slag, modified ettringite particles, aluminum sulfate, polycarboxylate superplasticizer, cetyltriethylammonium bromide, and potassium hydroxide was 100:10:17:9:4:10.

[0062] The specific surface area of ​​the obtained high-activity and high-stability steel slag is 526m² / kg, and the particle size characteristic value d 50 It is 25.7μm.

[0063] Step 4: Preparation of modified red mud Red mud, magnesium hydroxide, desulfurization ash, and calcium oxide were added to deionized water and stirred at a stirring rate of 300 r / min to form a mixed slurry A. N-methyldiethanolamine was added dropwise to the mixed slurry A. After the addition was complete, CO2 gas was introduced into the mixed slurry A to adjust the pH to 9. The mixed slurry A was then transferred to a microwave reactor. The amount of deionized water added was 4 times the mass of the red mud.

[0064] After the mixed slurry A was transferred to a microwave reactor, the microwave frequency was set to 2.5 GHz, and the mixed slurry A was subjected to microwave treatment for 15 minutes. After the microwave treatment was completed, a 10 wt % ferric chloride solution was added to the mixed slurry A, and the reaction was continued with stirring for 15 minutes to obtain a mixed slurry B.

[0065] The mixed slurry B was centrifuged at a speed of 1200 r / min for 30 minutes to retain the solid. The obtained solid was vacuum dried at 60° C. for 6 hours. The dried solid was crushed into particles with a particle size of ≤75 μm to obtain modified red mud.

[0066] The mass ratio of red mud, magnesium hydroxide, N-methyldiethanolamine, desulfurization ash, calcium oxide and ferric chloride solution used in this step is 20:3:9:5:4:22.

[0067] Step 5: Compounding cementitious materials from multiple sources of solid waste 1. First, add carbide slag, desulfurization ash, and yellow phosphorus slag into a drum mixer and stir at room temperature while spraying deionized water. Stir and react for 60 minutes. After stirring, let it stand and age for 12 hours. Dry the aged materials and crush them into particles with a particle size of ≤1mm to obtain premix A. The mass ratio of carbide slag, desulfurization ash, yellow phosphorus slag, and deionized water used is 3:15:18:40.

[0068] 2. Add premix A, high-activity and high-stability steel slag, modified red mud, alkali residue, desulfurization gypsum, slag, and calcium sulfoaluminate into a high-speed grinder and grind for 30 minutes to obtain a multi-source solid waste-based cementitious material; the mass ratio of premix A, high-activity and high-stability steel slag, modified red mud, alkali residue, desulfurization gypsum, slag, and calcium sulfoaluminate used is 35:60:26:7:10:17:23.

[0069] Example 4: A method for preparing a multi-source solid waste-based cementitious material The following steps are involved: Step 1: Preparation of modified ettringite particles 1. Dissolve aluminum sulfate in deionized water and stir at room temperature for 30 minutes until it is completely dissolved to form an aluminum sulfate solution; add desulfurized gypsum to the aluminum sulfate solution, then add calcium hydroxide, and stir evenly to obtain a suspension; the mass ratio of desulfurized gypsum, calcium hydroxide, aluminum sulfate, and deionized water is 12:4:5:50.

[0070] 2. Add the suspension to the autoclave and pressurize it with nitrogen. Stop adding nitrogen when the pressure in the autoclave reaches 5.97 MPa. Start stirring and start heating at a stirring rate of 200 r / min and a heating rate of 8°C / min. Heat to 180°C and stop heating. Maintain heat and pressure for 5 hours, at which point the pressure is 10.6 MPa. After 5 hours of heat and pressure, cool at a rate of 10°C / min. After the autoclave temperature drops to room temperature, release the nitrogen and remove the reaction liquid from the autoclave for later use.

[0071] 3. Add polyvinyl alcohol and N-β-aminoethyl-γ-aminopropyltrimethoxysilane to the reaction solution and ultrasonicate at 95°C for 4 hours. After the ultrasonication, filter the reaction solution and retain the solid, which is then dried and crushed to obtain modified ettringite particles. The amount of polyvinyl alcohol added is 10% by weight of the reaction solution, and the amount of N-β-aminoethyl-γ-aminopropyltrimethoxysilane added is 5% by weight of the reaction solution. The ultrasonication frequency is 34 kHz.

[0072] The obtained modified ettringite particles, d 50 =140nm; the surface hydroxyl density was measured by Boehm titration and was 5.1mmol / g.

[0073] Step 2: Initial stabilization of slag 1. Pour the liquid slag into the slag stewing tank, add water from the bottom until the slag is submerged, drain the water after soaking for 1 hour, and continue stewing at 300℃ for 5 hours to pulverize the slag. After the stewing is completed, dig out the pulverized slag from the slag stewing tank and set aside.

[0074] 2. First, the pulverized steel slag is passed through a 5mm sieve to remove coarse particles and impurities. Then, the metallic iron is separated by magnetic separation using a high-gradient magnetic separator with a magnetic field strength of 1.2T and a separation speed of 1m / min. The steel slag after magnetic separation is subjected to microwave treatment with a controlled microwave frequency of 2.4GHz, a temperature of 600°C, and a treatment time of 15min. After the microwave treatment, the stabilized steel slag is obtained.

[0075] Step 3: Activation of slag Stabilized steel slag and modified ettringite particles were first added to a grinder and ground for 20 minutes. Aluminum sulfate, polycarboxylate superplasticizer, cetyltriethylammonium bromide, and potassium hydroxide were then added and ground for another 10 minutes. Highly active and stable steel slag was obtained after grinding. The mass ratio of stabilized steel slag, modified ettringite particles, aluminum sulfate, polycarboxylate superplasticizer, cetyltriethylammonium bromide, and potassium hydroxide was 90:10:10:6:5:10.

[0076] The specific surface area of ​​the obtained high-activity and high-stability steel slag is 511m² / kg, and the particle size characteristic value d 50 It is 21.2μm.

[0077] Step 4: Preparation of modified red mud Red mud, magnesium hydroxide, desulfurization ash, and calcium oxide were added to deionized water and stirred at a stirring rate of 300 r / min to form a mixed slurry A. N-methyldiethanolamine was added dropwise to the mixed slurry A. After the addition was complete, CO2 gas was introduced into the mixed slurry A to adjust the pH to 9. The mixed slurry A was then transferred to a microwave reactor. The amount of deionized water added was 3 times the mass of the red mud.

[0078] After the mixed slurry A was transferred to a microwave reactor, the microwave frequency was set to 2.5 GHz, and the mixed slurry A was subjected to microwave treatment for 15 minutes. After the microwave treatment was completed, a 10 wt % ferric chloride solution was added to the mixed slurry A, and the reaction was continued with stirring for 25 minutes to obtain a mixed slurry B.

[0079] The mixed slurry B was centrifuged at a speed of 1200 r / min for 20 minutes to retain the solid. The obtained solid was vacuum dried at 60° C. for 6 hours. The dried solid was crushed into particles with a particle size of ≤75 μm to obtain modified red mud.

[0080] The mass ratio of red mud, magnesium hydroxide, N-methyldiethanolamine, desulfurization ash, calcium oxide and ferric chloride solution used in this step is 34:7:9:5:4:20.

[0081] Step 5: Compounding cementitious materials from multiple sources of solid waste 1. First, add carbide slag, desulfurization ash, and yellow phosphorus slag into a drum mixer and stir at room temperature while spraying deionized water. Stir and react for 60 minutes. After stirring, let it stand and age for 6 hours. Dry the aged materials and crush them into particles with a particle size of ≤1mm to obtain premix A. The mass ratio of carbide slag, desulfurization ash, yellow phosphorus slag, and deionized water used is 3:15:18:40.

[0082] 2. Add premix A, high-activity and high-stability steel slag, modified red mud, alkali residue, desulfurization gypsum, slag, and calcium sulfoaluminate into a high-speed grinder and grind for 30 minutes to obtain a multi-source solid waste-based cementitious material; the mass ratio of premix A, high-activity and high-stability steel slag, modified red mud, alkali residue, desulfurization gypsum, slag, and calcium sulfoaluminate used is 35:55:26:11:16:20:28.

[0083] Comparative Example 1 In this comparative example, stabilized steel slag is directly used to replace high-activity and high-stability steel slag, and unmodified red mud is used to replace modified red mud. Solid waste cementitious materials are prepared by compounding with carbide slag, desulfurization ash, yellow phosphorus slag, alkali residue, desulfurization gypsum, slag, and calcium sulfoaluminate. The raw material processing conditions and processing methods are consistent with step 5 in Example 1. The specific preparation method is as follows: 1. First, add carbide slag, desulfurization ash, and yellow phosphorus slag into a drum mixer and stir at room temperature while spraying deionized water. Stir and react for 60 minutes. After stirring, let it stand and age for 12 hours. Dry the aged materials and crush them into particles with a particle size of ≤1mm to obtain premix A. The mass ratio of carbide slag, desulfurization ash, yellow phosphorus slag, and deionized water used is 6:10:12:30.

[0084] 2. Add premix A, stabilized steel slag, red mud, alkali residue, desulfurized gypsum, slag, and calcium sulfoaluminate into a high-speed grinder and grind for 30 minutes to obtain a solid waste-based cementitious material; the mass ratio of premix A, stabilized steel slag, red mud, alkali residue, desulfurized gypsum, slag, and calcium sulfoaluminate used is 25:65:26:7:10:17:26.

[0085] Performance Test (I) Steel Slag Activity Index Test and Stability Test According to the mixing, stirring, molding, curing, and testing methods specified in the "Test Method for Cement Mortar Strength" (GB / T 17671-2021), 40 mm × 40 mm × 160 mm prismatic mortar specimens were prepared using the high-activity and high-stability steel slag prepared in Examples 1-4 and the stabilized steel slag used in Comparative Example 1, along with cement, water, and standard sand at a water-cement ratio of 0.5. The specimens were cured for 7 days. After curing, the mortar specimens were tested for volume stability and activity index. The mortar specimen mix design and performance test results are shown in Table 1.

[0086] The stability of steel slag is reflected in the volume expansion value of the mortar. The smaller the volume expansion value, the higher the stability. The volume expansion value is tested using the Redger clamp method specified in the "Test Method for Water Consumption, Setting Time and Stability of Cement at Standard Consistency" (GB / T1346-2011). A volume expansion value of ≤5mm is considered acceptable.

[0087] The activity index of steel slag is calculated based on the ratio of the compressive strength of the mortar specimen to the compressive strength of the control mortar specimen. The activity index calculation formula is: K=(R s / R c )*100%; K: activity index of steel slag powder (%); R s : compressive strength of steel slag-cement mortar specimen (MPa); R c : Compressive strength of cement mortar specimens (MPa).

[0088] Table 1 Design scheme of mortar specimen component mix ratio and performance test results Experimental groups 42.5# cement / g Steel slag / g Water / g Standard sand / g Compressive strength / MPa Activity index (%) Volume expansion value / mm comparison 900 0 450 2700 42.6 100 0 Example 1 630 270 450 2700 39.2 92 0.5 Example 2 630 270 450 2700 38.8 91.1 0.6 Example 3 630 270 450 2700 38.6 90.6 0.2 Example 4 630 270 450 2700 39.0 91.5 0.3 Comparative Example 1 630 270 450 2700 28.3 66.4 6.8 Analysis of the data in Table 1 shows that the high-activity and high-stability steel slag prepared in Examples 1 to 4 has an activity index of more than 90%, and a volume expansion value of 0.2 to 0.6 mm.

[0089] Performance Test (II) Performance Test of Multi-source Solid Waste-based Cementitious Materials for Solidifying Organic Soft Soil Preparation method of specimens for testing the performance of organic soft soil solidified by multi-source solid waste-based cementitious materials: According to the "Cement-Soil Mix Design Code" (JGJ / T 233-2011), standard specimens were prepared as follows: Standard specimen preparation: Water and multi-source solid waste-based cementitious material were added to a blender at a water-cement ratio of 0.5:1 and stirred to obtain a curing agent slurry. The curing agent slurry was added to the test soil and stirred again in a blender to obtain a cured organic soft soil mixture. The curing agent content was 25%, and the test soil was organic soft soil with an initial moisture content of 45% and a particle size of 60-200 μm.

[0090] The solidified organic soft soil mixture was poured into a 70.7mm × 70.7mm × 70.7mm cube mold (the inner surface of the mold was evenly coated with petroleum jelly) in two batches. After each injection, the mixture was evenly tamped 15 times in a clockwise direction from the edge to the center. When tamping the bottom layer, the tamping rod must reach the bottom of the mold; when tamping the upper layer, the tamping rod must penetrate the layer and reach 5-15mm below it. After each layer, the mixture was moved to a concrete vibrating table for compaction and removal of internal bubbles. After compaction, the mixture was slightly higher than the top of the mold. The mold top was smoothed with a ruler, then covered with plastic film. The specimen and mold were placed in a standard constant temperature and humidity curing chamber for curing at 20±1°C and ≥95% humidity. After 48 hours of curing, the specimen was demolded, marked, and then wrapped with plastic film to seal the specimen. The specimen was then placed in a curing chamber for 28 days.

[0091] According to the above method, the multi-source solid waste-based cementitious materials obtained in Examples 1 to 4 and the solid waste-based cementitious materials obtained in Comparative Example 1 were respectively prepared into multi-source solid waste-based cementitious materials solidified organic soft soil standard specimens. At the same time, 42.5# cement was used to prepare a cement-solidified organic soft soil standard specimen for comparison. The performance test was performed according to the following method: Performance testing method: Unconfined compressive strength: Tested in accordance with JTG 3430-2020, "Highway Geotechnical Test Code." The test equipment is a WDW-100 electronic universal testing machine. The axial strain rate is controlled at 2 mm / min, and the axial load is applied uniformly. After the specimen reaches peak stress and the axial strain continues to change by 3% to 5%, the pressure is stopped.

[0092] Water stability coefficient: tested according to CJ / T 486-2015 "Soil Stabilization Admixture" standard, water stability coefficient γ W =R W / R0*100,R W is the unconfined compressive strength of the specimen after immersion in water for 1 day, and R0 is the unconfined compressive strength of the specimen.

[0093] The mass loss rate was determined by using the freeze-thaw cycle method T0858-2009 in the Test Procedure for Stabilized Materials with Inorganic Binders for Highway Engineering (JTG E51-2009). The mass loss rate was tested after five cycles.

[0094] pH values ​​were measured according to the "Toxicity Extraction Methods for Solid Waste Leaching - Horizontal Oscillation Method" (HJ 557-2010). The top 5 mm of the specimen was removed and then crushed through a 3 mm sieve to remove coarse particles. A 100 g dry weight sample was weighed and placed in a 2 L extraction bottle. The extractant was added at a liquid-to-solid ratio of 10:1. The bottle was tightly capped and fixed vertically on a horizontal oscillator. The oscillation frequency was adjusted to 120 times / min and the amplitude was 40 mm. After oscillation at room temperature for 8 h, the extraction bottle was removed and allowed to stand for 16 h. The filtrate was then vacuum filtered through a 0.45 μm filter membrane. The filtrate was collected and the pH value was measured using a pH meter.

[0095] Lead leaching concentration was tested according to the "Solid Waste Leaching Toxicity Leaching Method - Horizontal Oscillation Method" (HJ 557-2010). The specimens were prepared as above, and the filtrate was collected and tested for lead leaching concentration.

[0096] The test results of the performance of organic soft soil solidified by multi-source solid waste-based cementitious materials are shown in Table 2.

[0097] Table 2 Test results of performance of organic soft soil solidified by multi-source solid waste-based cementitious materials pilot projects Example 1 Solidification of organic soft soil Example 2 Solidification of organic soft soil Example 3 Solidification of organic soft soil Example 4 Solidification of organic soft soil 42.5# cement solidified organic soft soil Comparative Example 1 Solidification of organic soft soil Unconfined compressive strength (MPa) 1.55 1.52 1.63 1.66 1.58 1.04 Water stability coefficient (%) 91.1 89.4 90.2 88.7 90.5 71.8 Mass loss rate (%) 3.8 3.2 3.5 3.4 4.4 11.6 pH 9.8 9.3 9.0 9.4 11.2 12.5 Lead leaching concentration (mg / L) 0.004 0.006 0.004 0.005 0.008 0.096 Surface cracks / deformation (visual) none none none none none 8 cracks, deformation Analysis of the data in Table 2 shows that the unconfined compressive strength of the organic soft soils solidified with the multi-source solid waste-based cementitious materials in Examples 1-4 ranged from 1.52 to 1.66 MPa, the water stability coefficient reached 88.7 to 91.1%, the pH value was 9.0 to 9.8, and the lead leaching concentration was 0.004 to 0.006 mg / L. These data demonstrate that the organic soft soils solidified with the multi-source solid waste-based cementitious materials in Examples 1-4 exhibited high unconfined compressive strength and water stability coefficient, and low mass loss rate. Furthermore, the pH value and lead leaching concentration of the organic soft soils solidified with the multi-source solid waste-based cementitious materials in Examples 1-4 were lower than those of the organic soft soils solidified with cement, demonstrating that the multi-source solid waste-based cementitious materials provided by the present invention offer superior performance, safety, and environmental friendliness.

[0098] Obviously, there are many specific implementation methods that can be changed under the concept of the present invention. Here, it should be stated that any changes made under the inventive concept of the present invention will fall within the scope of protection of the present invention.

Claims

1. A multi-source solid waste-based cementitious material, characterized by: Ingredients include: Carbide slag, desulfurization ash, yellow phosphorus slag, high-activity and high-stability steel slag, modified red mud, alkali slag, desulfurization gypsum, slag, calcium sulfoaluminate; The high-activity and high-stability steel slag is prepared by subjecting liquid steel slag to a preliminary stabilization treatment and then to steel slag activation. The steel slag activation is prepared by subjecting the stabilized steel slag to modified ettringite particles, aluminum sulfate, polycarboxylate water reducer, hexadecyltriethylammonium bromide, and potassium hydroxide to high-activity and high-stability steel slag. The modified red mud is prepared from red mud, magnesium hydroxide, N-methyldiethanolamine, desulfurization ash, calcium oxide, and ferric chloride solution; The modified ettringite particles adopt polyvinyl alcohol and N-β-aminoethyl-γ-aminopropyltrimethoxysilane as modifiers.

2. The multi-source solid waste-based cementitious material according to claim 1, characterized in that: The mass ratio of the stabilized steel slag, modified ettringite particles, aluminum sulfate, polycarboxylate water reducer, hexadecyltriethylammonium bromide, and potassium hydroxide is (90-100): (8-15): (10-17): (6-9): (4-8): (10-15).

3. The multi-source solid waste-based cementitious material according to claim 1, characterized in that: The mass ratio of the raw materials of the modified red mud, red mud, magnesium hydroxide, N-methyldiethanolamine, desulfurization ash, calcium oxide, and ferric chloride solution is (20-34): (3-7): (5-9): (2-5): (1-4): (17-22); the concentration of the ferric chloride solution is 10 wt%.

4. The method for preparing a multi-source solid waste-based cementitious material according to any one of claims 1 to 3, characterized in that: The invention comprises the steps of preparing modified ettringite microparticles, preliminary stabilization treatment of steel slag, excitation and activation of steel slag, preparation of modified red mud, and composite cementitious materials of multi-source solid wastes; the preparation of modified ettringite microparticles comprises the following steps: dissolving aluminum sulfate in deionized water to form an aluminum sulfate solution, adding desulfurized gypsum and calcium hydroxide to the aluminum sulfate solution, and stirring evenly to obtain a suspension; adding the suspension to a high-pressure reactor and pressurizing it, starting stirring and starting to heat up to 170-190°C, maintaining the temperature and pressure for reaction for 3-5 hours, adding polyvinyl alcohol and N-β-aminoethyl-γ-aminopropyltrimethoxysilane to the reaction solution, and ultrasonically treating the reaction solution for 2-4 hours to obtain modified ettringite microparticles.

5. The method for preparing a multi-source solid waste-based cementitious material according to claim 4, characterized in that: The modified red mud is prepared by the following method: adding red mud, magnesium hydroxide, calcium oxide, and desulfurization ash into deionized water, stirring uniformly to form a mixed slurry A, adding N-methyldiethanolamine dropwise to the mixed slurry A, introducing CO2 gas, and adjusting the pH value of the mixed slurry A to 9-10; and subjecting the mixed slurry A to microwave treatment; After the microwave treatment is completed, ferric chloride solution is added to the mixed slurry A and reacted for 15 to 25 minutes to obtain a mixed slurry B; the mixed slurry B is centrifuged and the solid is retained, and the obtained solid is vacuum dried and crushed to obtain modified red mud.

6. The method for preparing a multi-source solid waste-based cementitious material according to claim 4, characterized in that: The pressurization is to control the pressure in the autoclave to be 5.96-6.0 MPa.

7. The method for preparing a multi-source solid waste-based cementitious material according to claim 4, characterized in that: The preliminary stabilization treatment of the steel slag is as follows: the liquid steel slag is poured into a slag stewing pool for hot stewing, and after the steel slag is pulverized, it is screened, magnetically separated, and microwave-treated to obtain the stabilized steel slag; the hot stewing is carried out at a controlled temperature of 300-350°C and a hot stewing time of 4-5 hours; the microwave treatment is carried out at a microwave frequency of 2.4-2.5 GHz and a treatment time of 15-30 minutes.

8. The method for preparing a multi-source solid waste-based cementitious material according to claim 4, characterized in that: The steel slag activation process comprises the following steps: mixing the stabilized steel slag with modified ettringite particles and adding the mixture to a grinding mill for grinding; the grinding time is 20 to 30 minutes; and then adding aluminum sulfate, polycarboxylate water reducer, hexadecyltriethylammonium bromide, and potassium hydroxide to the grinding mill for continued grinding; the continued grinding time is 10 to 20 minutes.

9. The method for preparing a multi-source solid waste-based cementitious material according to claim 4, characterized in that: The multi-source solid waste composite cementitious material is prepared by first synthesizing a premix A from carbide slag, desulfurization ash, yellow phosphorus slag, and deionized water; then adding the premix A, high-activity and high-stability steel slag, modified red mud, alkali residue, desulfurization gypsum, slag, and calcium sulfoaluminate into a pulverizer and grinding for 20 to 30 minutes to obtain a multi-source solid waste-based cementitious material.

10. The method for preparing a multi-source solid waste-based cementitious material according to claim 9, characterized in that: The mass ratio of the carbide slag, desulfurization ash, yellow phosphorus slag, and deionized water is (3-7): (10-15): (12-18): (30-40); the mass ratio of the premix A, high-activity and high-stability steel slag, modified red mud, alkali residue, desulfurization gypsum, slag, and calcium sulfoaluminate is (23-35): (55-66): (20-26): (7-11): (8-16): (17-25): (21-28).