All-solid-waste fluid-state solidified soil and preparation method thereof

Abstract

The invention belongs to the technical field of building materials, and particularly relates to all-solid-waste fluid-state solidified soil and a preparation method thereof. The all-solid-waste fluid-state solidified soil is prepared from the following components in parts by weight: 25 to 45 parts of modified red mud, 25 to 45 parts of modified diatomite, 10 to 30 parts of desulfurized gypsum, 90 to 110 parts of iron tailing slag, 35 to 55 parts of clay, 0.01 to 1 part of hyperdispersant, 0.01 to 2 parts of expanding agent, 0.01 to 0.5 part of internal curing agent and 75 to 125 parts of water. The all-solid-waste fluid-state solidified soil provided by the invention has the advantages of good fluidity, high strength, good volume stability, low cost and the like, and is suitable for various projects such as foundation backfilling, site leveling and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of building materials, and in particular relates to full-solid waste fluidized solidified soil and a preparation method thereof. Background Art

[0002] In recent years, premixed fluidized solidified soil has emerged as a novel backfill material and has been widely used in various filling projects. As an engineering material with stable quality and moderate strength, premixed fluidized solidified soil is not only suitable for conventional scenarios such as municipal pipe gallery foundation trenches, pipe network laying, and deep foundation pit backfilling of buildings, but can also effectively deal with the difficulties of backfilling in narrow or irregular spaces, as well as the management of mine goafs, significantly reducing the difficulties of mechanical compaction and uneven settlement caused by space limitations, thereby effectively avoiding potential engineering risks. However, the existing premixed fluidized soil technology system still faces two major challenges: First, most current research relies on cement or cement clinker as the main base material, supplemented by fly ash, slag and other materials to prepare fluidized soil, in which the proportion of cement is relatively high; given that the production of cement is accompanied by high energy consumption and high carbon emissions, the cement industry accounts for about 15% of the total national carbon dioxide emissions, and this environmental problem cannot be ignored; second, in order to give the premixed fluidized soil ideal fluidity, the current preparation process often requires the addition of water that far exceeds the actual hydration requirements of the curing agent. Although this approach ensures the fluidity of the material, it is easy to cause significant volume shrinkage and cracking risks during the subsequent drying process, which in turn poses a potential threat to the quality of the project. Therefore, it is of great significance to use solid waste to develop fluidized soil with high fluidity, high strength and low shrinkage. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a full-solid waste fluidized solidified soil and a preparation method thereof in view of the deficiencies in the prior art. The full-solid waste fluidized solidified soil has the advantages of good fluidity, high strength, good volume stability, low cost, etc., and is suitable for various foundation backfilling, site leveling and other projects.

[0004] The technical solution adopted by the present invention to solve the above-mentioned problems is:

[0005] A fully solid waste fluidized solidified soil comprises the following components by weight: 25-45 parts of modified red mud, 25-45 parts of modified diatomaceous earth, 10-30 parts of desulfurized gypsum, 90-110 parts of iron tailings, 35-55 parts of clay, 0.01-1 parts of super dispersant, 0.01-2 parts of expansion agent, 0.01-0.5 parts of internal curing agent and 75-125 parts of water.

[0006] In the above scheme, the preparation method of the modified red mud comprises the following steps: dehydrating and drying the red mud to obtain red mud powder, weighing 1-3 g of the red mud powder and mixing it with 0.1-1 mL of 3-glycidyloxypropyltrimethoxysilane, adding it to 10-30 mL of water, ultrasonically oscillating for 5-15 minutes to disperse it evenly, then dripping 1-3 mL of 0.05-0.15 mol / L hydrogen peroxide solution, adjusting the pH value to 3-4 with hydrochloric acid, transferring the obtained mixture to a reactor, and placing the reactor in a magnetic stirrer at 40-60 ° C. In a force agitator, keep stirring for hydrolysis reaction for 20-40 minutes, then slowly add 3-8 mL of 8% sodium p-aminobenzenesulfonate aqueous solution, keep stirring at the same time and heat to 80-100° C. at a rate of 1-3° C. / s, then keep sealed, keep the pressure between 0.5-1 MPa and continue to react for 0.5-1.5 hours, filter, wash and dry after the reaction, roast at 500-700° C. for 1.5-2.5 hours, and grind for 20-40 minutes after cooling to obtain the modified red mud.

[0007] In the above scheme, the preparation method of the modified diatomite comprises the following steps:

[0008] (1) dehydrating and drying diatomaceous earth to obtain diatomaceous earth powder and mixing it with a citric acid aqueous solution having a mass concentration of 3% to 8% at a mass ratio of 1:(4-6), stirring at room temperature for 1-3 hours, filtering, washing, and drying to obtain pretreated diatomaceous earth;

[0009] (2) Pretreated diatomaceous earth and a polyvinyl alcohol aqueous solution with a mass concentration of 2%-5% are mixed at a mass ratio of 1:(9-11), stirred at 50-70° C. for 3-5 hours, filtered, washed, and dried, calcined at 400-600° C. for 1.5-2.5 hours, and ground for 10-30 minutes after cooling to obtain the modified diatomaceous earth.

[0010] In the above scheme, the preparation method of the hyperdispersant comprises the following steps:

[0011] 1) dissolving 90-110 g of lignin in 180-220 ml of dimethyl sulfoxide, heating to 60-70° C., slowly dropping 45-55 g of dimethyl sulfate, maintaining the temperature at 60-70° C. for sulfonation reaction for 2-3 hours, slowly adding 25-35 g of acrylic acid and 1.5-2.5 g of p-toluenesulfonic acid, and continuing the reaction at 70-80° C. for 3-4 hours, and after the reaction, adjusting the pH to neutral, washing and drying to obtain modified lignin;

[0012] 2) 35-45 g of ethylene glycol and 25-35 g of maleic anhydride are heated to 120-140° C. in 130-170 ml of toluene, 0.8-1.2 g of a titanate catalyst is added, and an esterification reaction is carried out at 120-140° C. for 4-6 hours. After the esterification reaction is completed, 50-70 g of polyethylene glycol is added and the reaction is continued at 120-140° C. for 2-4 hours. After the reaction is completed, macromonomer A is obtained by distillation;

[0013] 3) 70-80 g of modified lignin and 15-25 g of macromonomer A are dissolved in 90-110 mL of deionized water, heated to 80-90° C., 1-5 g of sodium methyl propylene sulfonate, 1-5 g of allyl alcohol polyoxyethylene ether and 0.8-1.2 g of benzoyl peroxide are added in sequence, and copolymerization is carried out at 80-90° C. for 3-6 hours under nitrogen protection. After the reaction is completed, the pH is adjusted to neutral, filtered and dried to obtain the super dispersant.

[0014] In the above scheme, the desulfurized gypsum is a byproduct of flue gas desulfurization in a coal-fired power plant, and the content of Ca(SO4)(H2O)2 in the desulfurized gypsum is not less than 85%.

[0015] In the above scheme, the fineness modulus of the iron tailings is 0.7-1.5, and the total content of CaO and SiO2 in the iron tailings is 50%-60%.

[0016] In the above scheme, the maximum particle size of the clay is ≤20 mm, and the organic matter content in the clay is ≤5.0 wt%.

[0017] In the above scheme, the expansion agent is a magnesium oxide expansion agent.

[0018] In the above scheme, the internal curing agent is a high molecular weight water-absorbing resin, and its water absorption rate is not less than 200g / g.

[0019] The present invention also provides a preparation method of the above-mentioned all-solid waste fluidized solidified soil, comprising the following steps: weighing modified red mud, modified diatomaceous earth, desulfurized gypsum, iron tailings slag, clay, super dispersant, expansion agent, and internal curing agent according to a ratio, mixing them evenly, adding water and stirring for 3-5 minutes to obtain the all-solid waste fluidized solidified soil.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] (1) The present invention proposes a new all-solid waste fluidized solidification soil. By adopting a variety of solid waste materials such as modified red mud, modified diatomaceous earth, desulfurized gypsum, etc., with reasonable proportions, it achieves efficient utilization of solid waste resources and reduces environmental pollution. The prepared fluidized solidification soil has excellent properties such as high fluidity, high strength, self-compacting, and good volume stability, and is suitable for various complex construction environments.

[0022] (2) The present invention provides a method for preparing all-solid waste fluidized solidified soil, by introducing chemical reagents such as 3-glycidyloxypropyltrimethoxysilane and hydrogen peroxide to perform surface modification and structural modification on red mud, thereby improving the dispersibility and activity of the red mud, thereby enhancing its performance in the solidified soil; during the modification process, the oxidizing effect of hydrogen peroxide helps to remove impurities in the red mud, while the introduction of 3-glycidyloxypropyltrimethoxysilane enhances the bonding force between the red mud particles and the matrix material, thereby enhancing the strength and stability of the solidified soil.

[0023] (3) In the preparation method provided by the present invention, citric acid and polyvinyl alcohol are used to perform a two-step modification treatment on diatomite, which not only improves the dispersibility and stability of diatomite, but also enhances the compatibility and adhesion between diatomite and the matrix material by introducing organic functional groups, which helps diatomite to play a better reinforcing role in solidified soil.

[0024] (4) The preparation method provided by the present invention innovatively combines multiple steps such as lignin sulfonation, polyethylene glycol esterification and copolymerization reaction to obtain a complex structure containing multiple polar functional groups such as sulfonic acid group, carboxylate group, ester group, hydroxyl group and ether group. This structure gives the super dispersant excellent dispersibility and stability. It is adsorbed on the surface of soil particles, and significantly improves the dispersibility between soil particles through electrostatic repulsion, steric hindrance and hydration film lubrication, releasing free water wrapped by soil particles. Under the condition of ensuring the same fluidity, it can greatly reduce the water demand of fluidized solidified soil, which helps to improve the strength of solidified soil and reduce its shrinkage.

[0025] (5) In the preparation method provided by the present invention, red mud is used to provide the alkaline environment required for the volcanic ash reaction, diatomaceous earth provides SiO2 and Al2O3 required for the generation of cementitious substances such as hydrated calcium silicate and hydrated calcium aluminate (CSH, CAH), and desulfurized gypsum provides sulfate ions required for the generation of calcium sulfonate (AFt). The synergistic effect of the three promotes the strength growth of the solidified soil; the expansive agent reacts with the hydration product of the cementitious material to generate an expansive substance; the internal curing agent provides a continuous water supply for the hydration reaction of cement, expansive agent and other cementitious materials, making the hydration reaction more sufficient; the iron tailings slag adjusts the volume stability and crack resistance of the solidified soil, and the composite synergy of various materials significantly improves the strength of the solidified soil and improves the ability of the solidified soil to resist shrinkage deformation. DETAILED DESCRIPTION

[0026] The technical scheme of the present invention will be described in detail below in conjunction with specific embodiments, but the described embodiments are only partial embodiments of the present invention, and all other embodiments obtained by ordinary technicians in the field without creative work based on the embodiments in the present invention belong to the scope of protection of the present invention. In the following embodiments, unless otherwise specified, the reagents used are all commercially available chemical reagents.

[0027] In a specific implementation manner, the red mud used is Bayer red mud produced by Chalco Shanxi New Materials Co., Ltd.; the diatomaceous earth used is from Shandong Qingdao Shengtai Silicon Industry Co., Ltd.; the desulfurization gypsum used is from Yangluo Power Plant, and the content of Ca(SO4)(H2O)2 in the desulfurization gypsum is not less than 85%; the iron tailings used are Daye iron tailings, and the fineness modulus of the iron tailings is 0.7-1.5; the clay used is foundation pit soil, the maximum particle size of the clay is ≤20mm, and the organic matter content in the clay is ≤5.0wt%; the expansion agent used is FQY magnesium oxide expansion agent, which comes from Wuhan Sanyuan Special Building Materials Co., Ltd.; the internal curing agent used is a polymer absorbent resin with a water absorption rate of not less than 200g / g, which comes from Nantong Keli Absorbent Materials Co., Ltd.

[0028] The modified red mud used in the present invention comprises the following preparation steps: dehydrating and drying red mud to obtain red mud powder, weighing 2g of red mud powder and mixing with 0.5mL of 3-glycidyloxypropyltrimethoxysilane, adding to 20mL of water, ultrasonically oscillating for 10 minutes to disperse evenly, then dripping 2mL of 0.1mol / L hydrogen peroxide (H2O2) solution, using hydrochloric acid to adjust the pH value of the reaction system to 3-4, transferring the obtained mixture to an appropriate reactor, placing the reactor in a magnetic stirrer at 50°C, keeping stirring, and performing hydrolysis reaction for 30 minutes, then slowly dripping 5mL of 8% sodium p-aminobenzenesulfonate aqueous solution into the reactor, while keeping stirring, heating to 90°C at a rate of 2°C / s, then sealing the reactor, keeping the pressure at 0.8MPa, continuing the reaction for 1 hour, filtering and separating the product after the reaction, then washing and drying it, then roasting it at 600°C for 2h, and grinding it for 30min after cooling to obtain the modified red mud.

[0029] The modified diatomite used in the present invention comprises the following preparation steps: dehydrating and drying the diatomite to obtain diatomite powder, preparing a 5% concentration citric acid aqueous solution, mixing the diatomite powder and the citric acid aqueous solution in a ratio of 1:5, stirring at room temperature for 2 hours using a stirrer, filtering, washing and drying to obtain pretreated diatomite after the reaction is completed; preparing a 3% mass concentration polyvinyl alcohol aqueous solution, mixing the pretreated diatomite powder and the polyvinyl alcohol aqueous solution in a ratio of 1:10, stirring at 60 DEG C for 4 hours using a stirrer, filtering the product to separate the diatomite powder after the reaction is completed, then washing and drying the diatomite powder, then roasting at 500 DEG C for 2 hours, and grinding for 15 minutes after cooling to obtain the modified diatomite.

[0030] The preparation method of the hyperdispersant used in the present invention comprises the following steps: 1) dissolving 100g of lignin in 200ml of dimethyl sulfoxide, heating to 65°C, stirring evenly, slowly dropping 50g of dimethyl sulfate, keeping the reaction temperature at 65°C, and carrying out sulfonation reaction for 2.5 hours. After the sulfonation reaction is completed, slowly adding 30g of acrylic acid and 2g of p-toluenesulfonic acid, and continuing the reaction for 3.5 hours, keeping the temperature constant at 75°C during the reaction. After the reaction is completed, adjusting the pH to neutral, washing and drying, etc., to obtain a lignin derivative containing sulfonic acid groups and carboxylic acid groups, which is recorded as "modified lignin"; 2) heating 40g of ethylene glycol and 30g of maleic anhydride in 150ml of toluene to 130°C, adding 1g of tetrabutyl titanate, and carrying out The esterification reaction was carried out for 5 hours, and the reaction temperature was maintained at 130°C; after the esterification reaction was completed, 60g of polyethylene glycol was added and the reaction was continued for 3 hours, during which the temperature was kept constant at 130°C. After the reaction was completed, the solvent and unreacted raw materials were removed by distillation to obtain a polyether ester macromonomer containing ester groups, hydroxyl groups and ether groups, which was recorded as "macromonomer A"; 3) 75g of modified lignin and 20g of macromonomer A were dissolved in 100mL of deionized water, heated to 85°C, 3g of sodium methyl propylene sulfonate, 2g of allyl alcohol polyoxyethylene ether and 1g of benzoyl peroxide were added in sequence, stirred evenly, and copolymerized at 85°C for 4.5 hours under nitrogen protection. After the reaction was completed, a super dispersant was obtained by adjusting the pH to neutral, filtering, drying and other steps.

[0031] The invention provides a full-solid waste fluidized solidified soil, which comprises the following components in parts by weight: 25-45 parts of modified red mud, 25-45 parts of modified diatomaceous earth, 10-30 parts of desulfurized gypsum, 90-110 parts of iron tailings, 35-55 parts of clay, 0.01-1 parts of super dispersant, 0.01-2 parts of expansion agent, 0.01-0.5 parts of internal curing agent and 75-125 parts of water.

[0032] The present invention also provides a preparation method of the above-mentioned all-solid waste fluidized solidified soil, comprising the following steps: weighing modified red mud, modified diatomaceous earth, desulfurized gypsum, iron tailings slag, clay, super dispersant, expansion agent, and internal curing agent according to a ratio, mixing them evenly, adding water and stirring for 3-5 minutes to obtain the all-solid waste fluidized solidified soil.

[0033] Example 1

[0034] The all-solid waste fluidized solidified soil comprises the following components in parts by weight: 25 parts of modified red mud, 45 parts of modified diatomaceous earth, 20 parts of desulfurized gypsum, 90 parts of iron tailings, 55 parts of clay, 0.5 parts of super dispersant, 1 part of expansion agent, 0.3 parts of internal curing agent and 95 parts of water.

[0035] Example 2

[0036] The all-solid waste fluidized solidified soil comprises the following components in parts by weight: 30 parts of modified red mud, 40 parts of modified diatomaceous earth, 20 parts of desulfurized gypsum, 95 parts of iron tailings, 50 parts of clay, 0.8 parts of super dispersant, 0.5 parts of expansion agent, 0.2 parts of internal curing agent and 95 parts of water.

[0037] Example 3

[0038] The all-solid waste fluidized solidified soil comprises the following components in parts by weight: 35 parts of modified red mud, 35 parts of modified diatomaceous earth, 20 parts of desulfurized gypsum, 100 parts of iron tailings, 45 parts of clay, 0.1 parts of super dispersant, 2 parts of expansion agent, 0.5 parts of internal curing agent and 95 parts of water.

[0039] Example 4

[0040] The all-solid waste fluidized solidified soil comprises the following components in parts by weight: 40 parts of modified red mud, 30 parts of modified diatomaceous earth, 20 parts of desulfurized gypsum, 105 parts of iron tailings, 40 parts of clay, 0.01 parts of super dispersant, 0.01 parts of expansion agent, 0.01 parts of internal curing agent and 95 parts of water.

[0041] Example 5

[0042] The all-solid waste fluidized solidified soil comprises the following components in parts by weight: 45 parts of modified red mud, 25 parts of modified diatomaceous earth, 20 parts of desulfurized gypsum, 110 parts of iron tailings, 35 parts of clay, 1 part of super dispersant, 1.5 parts of expansion agent, 0.4 parts of internal curing agent and 95 parts of water.

[0043] Comparative Example 1

[0044] The fluidized solidified soil comprises the following components in parts by weight: 25 parts of red mud, 45 parts of diatomaceous earth, 20 parts of desulfurized gypsum, 90 parts of iron tailings, 55 parts of clay, 0.5 parts of super dispersant, 1 part of expansion agent, 0.3 parts of internal curing agent and 95 parts of water.

[0045] Note: The difference between this comparative example and Example 1 is that the red mud and diatomaceous earth in this comparative example are not modified.

[0046] Comparative Example 2

[0047] The fluidized solidified soil comprises the following components in parts by weight: 25 parts of modified red mud, 45 parts of modified diatomaceous earth, 20 parts of desulfurized gypsum, 90 parts of iron tailings, 55 parts of clay, 1 part of expansion agent, 0.3 parts of internal curing agent and 95 parts of water.

[0048] Note: The difference between this comparative example and Example 1 is that no hyperdispersant is added in this comparative example.

[0049] Comparative Example 3

[0050] The fluidized solidified soil comprises the following components in parts by weight: 25 parts of modified red mud, 45 parts of modified diatomaceous earth, 20 parts of desulfurized gypsum, 90 parts of iron tailings, 55 parts of clay, 0.5 parts of super dispersant and 95 parts of water.

[0051] Note: The difference between this comparative example and Example 1 is that no expansion agent or internal curing agent is added in this comparative example.

[0052] The solid waste fluidized solidified soil prepared in the above embodiment and the fluidized solidified soil prepared in the comparative example were tested for fluidity and compressive strength according to the "DBJ51 / T188-2022 Technical Standard for Engineering Application of Premixed Fluidized Solidified Soil"; the volume shrinkage test sample size was 40mm×40mm×160mm, and the sample was demoulded after curing for 1d after molding. The initial length (length, width, height) was measured with a vernier caliper, and the initial volume was calculated. The curing continued until the end of the period, and the volume of the sample cured to the age was measured and calculated. The shrinkage deformation of the sample was expressed as the volume shrinkage rate [(initial volume-age volume) / initial volume×100%]. The performance test results of the fluidized solidified soil obtained in each embodiment and comparative example are shown in Table 1:

[0053] Table 1 Performance test results of fluidized solidified soil obtained in the examples and comparative examples

[0054]

[0055] As shown in Table 1, the fluidity of the all-solid waste high-performance fluidized solidified soil prepared in the embodiment is relatively high, reaching 235-270mm; the 28d strength is relatively high, reaching 3-3.5MPa; the 28d volume shrinkage is relatively low, only 0.9%-0.15%. Compared with Example 1, the 28d compressive strength of Comparative Example 1 is significantly reduced, and the 28d volume shrinkage is significantly increased, indicating that the modified treatment of red mud and diatomaceous earth of the present invention helps to improve the strength and volume stability of the fluidized solidified soil; Compared with Example 1, the fluidity of Comparative Example 2 is significantly reduced, and the 28d strength is increased, indicating that when the water consumption is constant, the addition of the superdispersant of the present invention helps to improve the fluidity and strength of the fluidized solidified soil; Compared with Example 1, the 28d compressive strength of Comparative Example 3 is significantly reduced, and the 28d volume shrinkage is significantly increased, indicating that the addition of the expansion agent and the internal curing agent of the present invention helps to improve the strength and volume stability of the fluidized solidified soil.

[0056] In summary, the all-solid waste fluidized solidified soil provided by the present invention has the advantages of good fluidity, high strength, good volume stability, low cost, etc., and is suitable for various foundation backfilling, site leveling and other projects.

[0057] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solution and its improved conception within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A solid waste fluidized soil, characterized in that: The composition comprises the following components by weight: 25-45 parts of modified red mud, 25-45 parts of modified diatomaceous earth, 10-30 parts of desulfurized gypsum, 90-110 parts of iron tailings, 35-55 parts of clay, 0.01-1 parts of super dispersant, 0.01-2 parts of expansion agent, 0.01-0.5 parts of internal curing agent and 75-125 parts of water.

2. The all-solid waste fluidized solidified soil according to claim 1, characterized in that: The preparation method of the modified red mud comprises the following steps: dehydrating and drying the red mud to obtain red mud powder, weighing 1-3 g of the red mud powder and mixing it with 0.1-1 mL of 3-glycidyloxypropyltrimethoxysilane, adding the mixture to 10-30 mL of water, ultrasonically oscillating for 5-15 minutes to disperse the mixture evenly, then dripping 1-3 mL of 0.05-0.15 mol / L hydrogen peroxide solution, adjusting the pH value to 3-4 with hydrochloric acid, transferring the obtained mixture to a reactor, and placing the reactor under a magnetic stirring at 40-60° C. In the vessel, the stirring state is maintained for hydrolysis reaction for 20-40 minutes, and then 3-8 mL of an aqueous solution of sodium p-aminobenzenesulfonate with a mass concentration of 8% is slowly added, while the stirring state is maintained and the temperature is raised to 80-100° C. at a rate of 1-3° C. / s. Then, the sealed state is maintained, and the pressure is maintained between 0.5-1 MPa to continue the reaction for 0.5-1.5 hours. After the reaction is completed, it is filtered, washed, and dried, and roasted at 500-700° C. for 1.5-2.5 hours. After cooling, it is ground for 20-40 minutes to obtain the modified red mud.

3. The all-solid waste fluidized solidified soil according to claim 1, characterized in that: The preparation method of the modified diatomite comprises the following steps: (1) dehydrating and drying diatomaceous earth to obtain diatomaceous earth powder and mixing it with a citric acid aqueous solution having a mass concentration of 3% to 8% at a mass ratio of 1:(4-6), stirring at room temperature for 1-3 hours, filtering, washing, and drying to obtain pretreated diatomaceous earth; (2) Pretreated diatomaceous earth and a polyvinyl alcohol aqueous solution with a mass concentration of 2%-5% are mixed at a mass ratio of 1:(9-11), stirred at 50-70° C. for 3-5 hours, filtered, washed, and dried, calcined at 400-600° C. for 1.5-2.5 hours, and ground for 10-30 minutes after cooling to obtain the modified diatomaceous earth.

4. The all-solid waste fluidized solidified soil according to claim 1, characterized in that: The preparation method of the hyperdispersant comprises the following steps: 1) dissolving 90-110 g of lignin in 180-220 ml of dimethyl sulfoxide, heating to 60-70° C., slowly dropping 45-55 g of dimethyl sulfate, maintaining the temperature at 60-70° C. for sulfonation reaction for 2-3 hours, slowly adding 25-35 g of acrylic acid and 1.5-2.5 g of p-toluenesulfonic acid, and continuing the reaction at 70-80° C. for 3-4 hours, and after the reaction, adjusting the pH to neutral, washing and drying to obtain modified lignin; 2) 35-45 g of ethylene glycol and 25-35 g of maleic anhydride are heated to 120-140° C. in 130-170 ml of toluene, 0.8-1.2 g of a titanate catalyst is added, and an esterification reaction is carried out at 120-140° C. for 4-6 hours. After the esterification reaction is completed, 50-70 g of polyethylene glycol is added and the reaction is continued at 120-140° C. for 2-4 hours. After the reaction is completed, macromonomer A is obtained by distillation; 3) 70-80 g of modified lignin and 15-25 g of macromonomer A are dissolved in 90-110 mL of deionized water, heated to 80-90° C., 1-5 g of sodium methyl propylene sulfonate, 1-5 g of allyl alcohol polyoxyethylene ether and 0.8-1.2 g of benzoyl peroxide are added in sequence, and copolymerization is carried out at 80-90° C. for 3-6 hours under nitrogen protection. After the reaction is completed, the pH is adjusted to neutral, filtered and dried to obtain the super dispersant.

5. The all-solid waste fluidized solidified soil according to claim 1, characterized in that: The desulfurized gypsum is a byproduct of flue gas desulfurization in a coal-fired power plant, and the content of Ca(SO4)(H2O)2 in the desulfurized gypsum is not less than 85%.

6. The all-solid waste fluidized solidified soil according to claim 1, characterized in that: The fineness modulus of the iron tailings is 0.7-1.5, and the total content of CaO and SiO2 in the iron tailings is 50%-60%.

7. The all-solid waste fluidized solidified soil according to claim 1, characterized in that: The maximum particle size of the clay is ≤20 mm, and the organic matter content in the clay is ≤5.0 wt %.

8. The all-solid waste fluidized solidified soil according to claim 1, characterized in that: The expansion agent is a magnesium oxide expansion agent.

9. The all-solid waste fluidized solidified soil according to claim 1, characterized in that: The internal curing agent is a high molecular weight water-absorbing resin, and its water absorption rate is not less than 200g / g.

10. The method for preparing the all-solid waste fluidized solidified soil according to any one of claims 1 to 9, characterized in that: The method comprises the following steps: weighing modified red mud, modified diatomaceous earth, desulfurized gypsum, iron tailings slag, clay, super dispersant, expansion agent and internal curing agent according to a proportion, mixing them evenly, adding water and stirring for 3-5 minutes to obtain the all-solid waste fluidized solidified soil.

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