Composite curing agent and preparation method of cured soil thereof

Abstract

The invention relates to the technical field of curing agent and solidified soil preparation, in particular to a composite curing agent and a solidified soil preparation method thereof.The solidified soil is prepared from Portland cement, calcium oxide, fly ash, gypsum, chopped fibers, zeolite, a microbial agent, ethylenediamine tetraacetic acid and alkyl sulfonate; the function of decomposing harmful substances in the polluted soil can be achieved while the strength of the solidified soil is met, and direct utilization of the polluted soil is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of preparation of curing agent and cured soil, and in particular to a composite curing agent and a method for preparing cured soil thereof. Background Art

[0002] With the continuous development of modern engineering technology, higher and higher requirements are put forward for the solidification treatment of materials such as soil and waste. Although traditional single curing agents, such as cement and lime, can meet the curing needs to a certain extent, their performance is limited and it is difficult to meet the complex and changing engineering environment.

[0003] In order to overcome the limitations of traditional curing agents, researchers began to explore the method of combining multiple curing agents. Composite curing agents came into being. They are composed of multiple chemical components. By optimizing the ratio and the selection of activators, complex hydration reactions and ion exchange reactions can occur, thus significantly improving the properties of soil or waste.

[0004] Solidified soil is a technology that uses chemical solidifiers or physical means to improve the structural properties of soil. It mixes soil with a solidifier and then forms a solid structure through a series of physical and chemical reactions to achieve a stable, safe and environmentally friendly treatment effect.

[0005] Chinese Patent Publication No.: CN114316996B discloses a composite curing agent and its preparation method, which includes 100 parts of a main agent, 50 parts of a reinforcing agent, 3 parts of a plasticizer, 10-15 parts of an activator and 0.1 parts of a water reducer by mass; the main agent is castor oil and / or palm oil, the reinforcing agent is one or more of bagasse, bamboo stems, and rapeseed cake, the plasticizer is furfuryl alcohol resin, furfural and aniline, the activator is a mixture of Al2(SO4)3 and KOH, and the water reducer is sodium carboxymethyl cellulose. The composite curing agent of the invention has a simple preparation process, a simple manufacturing process, and the raw materials are mostly ecological plant fibers. The manufacturing environment is pollution-free and the preparation conditions are mild. The soil curing agent can effectively reduce the liquid limit of high liquid limit soil, improve the plastic limit and soil strength, and improve the soil's impermeability and the defects of mud bubbling.

[0006] The existing technology also has the following problems: the solidifying agent in the existing technology solidifies the soil to improve the soil bearing capacity, but cannot decompose the pollutants in the soil, resulting in the inability to directly utilize the contaminated soil. Summary of the invention

[0007] To this end, the present invention provides a composite curing agent and a method for preparing the cured soil thereof, so as to overcome the problem in the prior art that the curing agent cannot decompose the pollutants in the soil, resulting in the inability to directly utilize the contaminated soil.

[0008] To achieve the above objectives, on the one hand, the present invention provides a composite curing agent, including silicate cement, calcium oxide, fly ash, gypsum, chopped fibers, zeolite, microbial agent, ethylenediaminetetraacetic acid and alkyl sulfonate.

[0009] Further, it comprises: 10-30 parts of silicate cement, 3-8 parts of calcium oxide, 40-60 parts of slag powder, 4-6 parts of gypsum, 1-3 parts of chopped fibers, 1-5 parts of zeolite, 1-5 parts of microbial agents, 1-10 parts of ethylenediaminetetraacetic acid and 1-10 parts of alkyl sulfonate.

[0010] Furthermore, the components of the composite curing agent include, by weight: 30 parts of Portland cement, 5 parts of calcium oxide, 50 parts of slag powder, 5 parts of gypsum, 3 parts of chopped fibers, 5 parts of zeolite, 3 parts of microbial agents, 5 parts of ethylenediaminetetraacetic acid and 5 parts of alkyl sulfonate.

[0011] Furthermore, the weight ratio of the zeolite to the microbial agent is 5:2-5:4.

[0012] Furthermore, the weight ratio of the ethylenediaminetetraacetic acid to the alkyl sulfonate is 1:1.

[0013] Furthermore, the length of the chopped fibers is 1-8 mm.

[0014] Furthermore, the preparation method of the composite curing agent comprises:

[0015] Step S1, inoculating a microbial agent onto zeolite to obtain zeolite agent powder;

[0016] Step S2, grinding calcium oxide and gypsum into powder respectively;

[0017] Step S3, sieving silicate cement, fly ash, calcium oxide and gypsum for later use;

[0018] Step S4, putting the sieved raw materials, zeolite inoculant powder, chopped fibers, ethylenediaminetetraacetic acid, and alkyl sulfonate into a blender in proportion and mixing them evenly to obtain a composite curing agent.

[0019] Furthermore, in step S1, the process of inoculating the microbial agent onto the zeolite to obtain the zeolite agent powder includes:

[0020] Step S11, washing the zeolite with deionized water and then sterilizing it;

[0021] Step S12, spraying the microbial agent on the zeolite, and drying it after curing for a preset time;

[0022] Step S13, grinding and sieving the dried zeolite inoculated with the microbial agent to obtain zeolite agent powder.

[0023] Furthermore, in step S12, the curing conditions include a curing temperature of 30-35° C. and a pH value of 7-8.

[0024] On the other hand, the present invention also provides a solidified soil prepared by using the composite solidifying agent, and the preparation method of the solidified soil comprises:

[0025] Determine the amount of composite curing agent added based on the weight of the contaminated soil;

[0026] Mix the composite curing agent and the contaminated soil according to the added amount, stir evenly and place in a mold;

[0027] After curing at room temperature for a certain period of time, the cured soil is removed from the mold.

[0028] Compared with the prior art, the beneficial effect of the present invention lies in that the present invention converts harmful substances into harmless or low-toxic forms through mechanisms such as adsorption, precipitation, and degradation by adding the cultivated microbial agent to the curing agent, and permanently fixes them in the solidified soil, thereby preventing the migration and release of harmful substances and reducing their long-term harm to the environment; using contaminated soil to prepare solidified soil for construction filling can save a large amount of traditional road construction or building materials, such as sand, gravel, cement, etc., which helps to reduce the exploitation and consumption of natural resources and reduce engineering costs, thereby achieving harmless treatment and direct utilization of contaminated soil.

[0029] Furthermore, the present invention increases the reaction activity by grinding the raw materials, and screening ensures that the curing agent can penetrate into the material more evenly during use, thereby improving the curing effect and overall strength, helping the cured soil to withstand a greater load during application, thereby achieving direct utilization of contaminated soil.

[0030] Furthermore, the present invention inoculates the microbial agent on zeolite, and through the adsorption and exchange effects of the zeolite, provides more nutrients and growth factors for the microorganisms, protects the microorganisms from the influence of adverse external factors, provides a stable environment for the microorganisms, and thus improves the survival rate of the microorganisms; the exchangeable cations in the zeolite can be exchanged with harmful ions in the contaminated soil, and the fixed microbial agent can maintain the optimal pollution reduction performance of the zeolite, while exerting the activity of the microbial agent in removing pollutants such as organic matter, ammonia nitrogen and phosphorus; through the synergistic effect of zeolite and microorganisms, the removal efficiency of the solidifying agent for pollutants is significantly improved, thereby further improving the direct utilization efficiency of the contaminated soil. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a flow chart of a method for preparing a composite curing agent according to an embodiment of the present invention;

[0032] Figure 2The present invention is a flowchart of a method for preparing solidified soil according to an embodiment of the present invention. DETAILED DESCRIPTION

[0033] In order to make the objects and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0034] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the protection scope of the present invention.

[0035] It should be noted that, in the description of the present invention, terms such as "up", "down", "left", "right", "inside" and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings. This is merely for the convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present invention.

[0036] In addition, it should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0037] The embodiment of the present invention provides a composite curing agent, which includes silicate cement, calcium oxide, fly ash, gypsum, chopped fibers, zeolite, microbial agent, ethylenediaminetetraacetic acid and alkyl sulfonate.

[0038] Specifically, the silicate cement is, for example, PO42.5 grade cement, which is not specifically limited; the silicate cement can react chemically with calcium hydroxide to generate calcium silicate and / or calcium silicate gel, and calcium silicate has high strength and durability. The calcium silicate gel can fill the gaps between the contaminated soil to make the structure more compact; at the same time, the calcium silicate gel also has high strength and water resistance, and can further improve the compression, flexural and durability of the solidified soil prepared using the composite curing agent.

[0039] Specifically, the calcium oxide has strong alkalinity and can effectively neutralize the acidic substances in the contaminated soil. The calcium oxide reacts with water to generate calcium hydroxide and releases a large amount of heat, which can accelerate the curing process.

[0040] Specifically, the chopped fibers are artificially synthesized polymer short fibers, which are evenly distributed in the solidified soil and can form a three-dimensional network structure, which can effectively restrict the movement of solidified soil particles and increase the overall strength and stability of the solidified soil; the chopped fibers can absorb and disperse stress and can effectively prevent the solidified soil from being damaged.

[0041] Specifically, the microbial agent is one or two of bacteria, fungi and actinomycetes, without specific limitation.

[0042] Specifically, the microbial agents are inoculated on zeolite, and through the adsorption and exchange effects of zeolite, more nutrients and growth factors are provided to the microorganisms, protecting the microorganisms from the influence of adverse external factors, providing a stable environment for the microorganisms, thereby improving the survival rate of the microorganisms; the exchangeable cations in the zeolite can be exchanged with harmful ions in the contaminated soil, and the fixed microbial agents can maintain the optimal pollution reduction performance of the zeolite, while exerting the activity of the microbial agents in removing pollutants such as organic matter, ammonia nitrogen and phosphorus. Through the synergistic effect of zeolite and microorganisms, the removal efficiency of the solidifying agent for pollutants is significantly improved.

[0043] Specifically, the slag powder reacts with the moisture in the contaminated soil, and while reducing the moisture content of the solidified soil, the generated gelling material can form a stable network structure, firmly combining the solidified soil particles together to prevent the separation and movement of the solidified soil particles, thereby improving the shear strength and impermeability of the solidified soil.

[0044] Specifically, the EDTA is a strong chelating agent that can form stable chelates with heavy metal ions or other metal ions in contaminated soil, which helps to reduce the interference of metal ions in the contaminated soil solidification process and improve the uniformity and stability of the solidified soil.

[0045] Specifically, the alkyl sulfonate is a surfactant that can reduce the surface tension between contaminated soil particles and help mix and disperse the curing agent in the contaminated soil.

[0046] Specifically, it includes: 10-30 parts of silicate cement, 3-8 parts of calcium oxide, 40-60 parts of slag powder, 4-6 parts of gypsum, 1-3 parts of chopped fibers, 1-5 parts of zeolite, 1-5 parts of microbial agents, 1-10 parts of ethylenediaminetetraacetic acid and 1-10 parts of alkyl sulfonate.

[0047] Specifically, the components of the composite curing agent include, by weight: 30 parts of silicate cement, 5 parts of calcium oxide, 50 parts of slag powder, 5 parts of gypsum, 3 parts of chopped fibers, 5 parts of zeolite, 3 parts of microbial agents, 5 parts of ethylenediaminetetraacetic acid and 5 parts of alkyl sulfonate.

[0048] Specifically, the weight ratio of the zeolite to the microbial agent is 5:2-5:4.

[0049] Specifically, the weight ratio of the ethylenediaminetetraacetic acid to the alkyl sulfonate is 1:1.

[0050] Specifically, the length of the chopped fibers is 1-8 mm.

[0051] See also Figure 1 As shown, it is a flow chart of the preparation method of the composite curing agent according to an embodiment of the present invention.

[0052] An embodiment of the present invention provides a method for preparing a composite curing agent, comprising:

[0053] Step S1, inoculating a microbial agent onto zeolite to obtain zeolite agent powder;

[0054] Step S2, grinding calcium oxide and gypsum into powder respectively;

[0055] Step S3, sieving silicate cement, fly ash, calcium oxide and gypsum for later use;

[0056] Step S4, putting the sieved raw materials, zeolite inoculant powder, chopped fibers, ethylenediaminetetraacetic acid, and alkyl sulfonate into a blender in proportion and mixing them evenly to obtain a composite curing agent.

[0057] Specifically, the mesh size of each raw material is set to [200 mesh, 400 mesh], and 300 mesh is preferred in the embodiment of the present invention.

[0058] Specifically, in step S1, the process of inoculating the microbial agent onto the zeolite to obtain the zeolite agent powder includes:

[0059] Step S11, washing the zeolite with deionized water and then sterilizing it;

[0060] Step S12, spraying the microbial agent on the zeolite, and drying it after curing for a preset time;

[0061] Step S13, grinding and sieving the dried zeolite inoculated with the microbial agent to obtain zeolite agent powder.

[0062] Specifically, the process of sterilizing the zeolite after washing it with deionized water includes:

[0063] The zeolite is thoroughly washed with deionized water to remove surface impurities and contaminants;

[0064] Place the cleaned zeolite into a sterile container and add deionized water until the zeolite is submerged;

[0065] After sealing the container, put it into a high-temperature and high-pressure sterilizer, and set the temperature of the sterilizer to 121°C and the pressure to 1.05 kg / cm 2 , continue sterilization for 30 minutes.

[0066] After sterilization, wait for the autoclave to cool to room temperature, take out the zeolite and perform subsequent operations under sterile conditions

[0067] Specifically, in step S12, the curing conditions include a curing temperature of 30-35° C. and a pH value of 7-8.

[0068] Specifically, the value range of the preset duration is set to [2d, 7d], and 3d is preferred in the embodiment of the present invention.

[0069] Specifically, the zeolite inoculated with the microbial agent is dried in an oven at a low temperature of 35°C.

[0070] See also Figure 2 As shown, it is a flow chart of a method for preparing solidified soil according to an embodiment of the present invention.

[0071] The embodiment of the present invention further provides a solidified soil prepared by a composite solidifying agent, wherein the preparation method of the solidified soil comprises:

[0072] Determine the amount of composite curing agent added based on the weight of the contaminated soil;

[0073] Mix the composite curing agent and the contaminated soil according to the added amount, stir evenly and place in a mold;

[0074] After curing at room temperature for a certain period of time, the cured soil is removed from the mold.

[0075] Specifically, the addition ratio of the composite curing agent is set to [4%, 10%], and 6% is preferred in the embodiment of the present invention.

[0076] The present invention is described and explained below by means of specific embodiments.

[0077] Embodiment 1:

[0078] Raw material components (by weight): 30 parts of Portland cement, 5 parts of calcium oxide, 50 parts of slag powder, 5 parts of gypsum, 3 parts of chopped fibers, 5 parts of zeolite, 3 parts of microbial agents, 5 parts of ethylenediaminetetraacetic acid and 5 parts of alkyl sulfonate.

[0079] Preparation method: Add 30 parts of treated silicate cement, 5 parts of calcium oxide, 50 parts of slag powder, 5 parts of gypsum, 3 parts of chopped fibers, 5 parts of zeolite, 3 parts of microbial agents, 5 parts of ethylenediaminetetraacetic acid and 5 parts of alkyl sulfonate into a mixing device, mix well to obtain a composite curing agent.

[0080] The composite curing agent is added at a ratio of 6% and mixed with the contaminated soil in proportion and then placed in a mold. After curing, the cured soil is taken out.

[0081] Embodiment 2:

[0082] Raw material components (by weight): 25 parts of silicate cement, 6 parts of calcium oxide, 48 parts of slag powder, 4 parts of gypsum, 3 parts of chopped fibers, 3 parts of zeolite, 2 parts of microbial agents, 7 parts of ethylenediaminetetraacetic acid and 7 parts of alkyl sulfonate.

[0083] Preparation method: 25 parts of silicate cement, 6 parts of calcium oxide, 48 parts of slag powder, 4 parts of gypsum, 3 parts of chopped fibers, 3 parts of zeolite, 2 parts of microbial agents, 7 parts of ethylenediaminetetraacetic acid and 7 parts of alkyl sulfonate are added into a mixing device and mixed evenly to obtain a composite curing agent.

[0084] The composite curing agent is added at a ratio of 8% and mixed with the contaminated soil in proportion and then placed in a mold. After curing, the cured soil is taken out.

[0085] Embodiment 3:

[0086] Raw material components (by weight): 10 parts of silicate cement, 6 parts of calcium oxide, 60 parts of slag powder, 4 parts of gypsum, 3 parts of chopped fibers, 5 parts of zeolite, 2 parts of microbial agents, 7 parts of ethylenediaminetetraacetic acid and 7 parts of alkyl sulfonate.

[0087] Preparation method: 10 parts of Portland cement, 6 parts of calcium oxide, 60 parts of slag powder, 4 parts of gypsum, 3 parts of chopped fibers, 5 parts of zeolite, 2 parts of microbial agents, 7 parts of ethylenediaminetetraacetic acid and 7 parts of alkyl sulfonate are added into a mixing device and mixed evenly to obtain a composite curing agent.

[0088] The composite curing agent is added at a ratio of 10% and mixed with the contaminated soil in proportion and then placed in a mold. After curing, the cured soil is taken out.

[0089] Embodiment 4:

[0090] Raw material components (by weight): 15 parts of silicate cement, 8 parts of calcium oxide, 55 parts of slag powder, 4 parts of gypsum, 3 parts of chopped fibers, 5 parts of zeolite, 2 parts of microbial agents, 4 parts of ethylenediaminetetraacetic acid and 4 parts of alkyl sulfonate.

[0091] Preparation method: 15 parts of silicate cement, 8 parts of calcium oxide, 55 parts of slag powder, 4 parts of gypsum, 3 parts of chopped fibers, 5 parts of zeolite, 2 parts of microbial agents, 4 parts of ethylenediaminetetraacetic acid and 4 parts of alkyl sulfonate are added into a mixing device and mixed evenly to obtain a composite curing agent.

[0092] The composite curing agent is added at a ratio of 10% and mixed with the contaminated soil in proportion and then placed in a mold. After curing, the cured soil is taken out.

[0093] Embodiment 5:

[0094] Raw material components (by weight): 20 parts of silicate cement, 4 parts of calcium oxide, 50 parts of slag powder, 4 parts of gypsum, 3 parts of chopped fibers, 4 parts of zeolite, 2 parts of microbial agents, 6 parts of ethylenediaminetetraacetic acid and 6 parts of alkyl sulfonate.

[0095] Preparation method: 20 parts of Portland cement, 4 parts of calcium oxide, 50 parts of slag powder, 4 parts of gypsum, 3 parts of chopped fibers, 4 parts of zeolite, 2 parts of microbial agents, 6 parts of ethylenediaminetetraacetic acid and 6 parts of alkyl sulfonate are added into a mixing device and mixed evenly to obtain a composite curing agent.

[0096] The composite curing agent is added at a ratio of 5% and mixed with the contaminated soil in proportion and then placed in a mold. After curing, the cured soil is taken out.

[0097] Embodiment 6:

[0098] Raw material components (by weight): 10 parts of Portland cement, 3 parts of calcium oxide, 40 parts of slag powder, 4 parts of gypsum, 1 part of chopped fibers, 4 parts of zeolite, 2 parts of microbial agents, 5 parts of ethylenediaminetetraacetic acid and 5 parts of alkyl sulfonates.

[0099] Preparation method: 10 parts of Portland cement, 3 parts of calcium oxide, 40 parts of slag powder, 4 parts of gypsum, 1 part of chopped fiber, 4 parts of zeolite, 2 parts of microbial agent, 5 parts of ethylenediaminetetraacetic acid and 5 parts of alkyl sulfonate are added into a mixing device and mixed evenly to obtain a composite curing agent.

[0100] The composite curing agent is added at a ratio of 10% and mixed with the contaminated soil in proportion and then placed in a mold. After curing, the cured soil is taken out.

[0101] Embodiment 7:

[0102] Raw material components (by weight): 30 parts of Portland cement, 8 parts of calcium oxide, 60 parts of slag powder, 6 parts of gypsum, 3 parts of chopped fibers, 5 parts of zeolite, 5 parts of microbial agents, 8 parts of ethylenediaminetetraacetic acid and 8 parts of alkyl sulfonate.

[0103] Preparation method: 30 parts of Portland cement, 8 parts of calcium oxide, 60 parts of slag powder, 6 parts of gypsum, 3 parts of chopped fibers, 5 parts of zeolite, 5 parts of microbial agents, 8 parts of ethylenediaminetetraacetic acid and 8 parts of alkyl sulfonate are added into a mixing device and mixed evenly to obtain a composite curing agent.

[0104] The composite curing agent is added at a ratio of 4% and mixed with the contaminated soil in proportion and then placed in a mold. After curing, the cured soil is taken out.

[0105] Comparative Example 1:

[0106] 30 parts of Portland cement, 5 parts of calcium oxide, 50 parts of slag powder, 5 parts of gypsum, 3 parts of chopped fibers, 5 parts of zeolite, 0 parts of microbial agent, 5 parts of ethylenediaminetetraacetic acid and 5 parts of alkyl sulfonate.

[0107] Preparation method: Add 30 parts of treated silicate cement, 5 parts of calcium oxide, 50 parts of slag powder, 5 parts of gypsum, 3 parts of chopped fibers, 5 parts of zeolite, 0 parts of microbial agent, 5 parts of ethylenediaminetetraacetic acid and 5 parts of alkyl sulfonate into a mixing device, mix well to obtain a composite curing agent.

[0108] The composite curing agent is added at a ratio of 6% and mixed with the contaminated soil in proportion and then placed in a mold. After curing, the cured soil is taken out.

[0109] 1. Solidified soil performance test

[0110] Several solidified soil samples were prepared according to the addition ratio in each embodiment. The samples for compressive strength test were cubes of 150mm×150mm×150mm, the samples for bending test were prisms of 150mm×150mm×600mm, and the samples for shear performance test were prisms of 150mm×150mm×75mm.

[0111] (1) Each solidified soil sample was placed on a universal testing machine and pressurized until it was destroyed, and the pressure strength at the time of destruction was recorded; (2) Each solidified soil sample was placed on a three-point bending device, and a bending force was applied to the specimen until the specimen broke, and the maximum bending force at the time of fracture was recorded, and the bending strength was calculated based on the maximum bending force; (3) Each solidified soil sample was placed on a shear test device, and a shear force was applied to the solidified soil specimen until the specimen broke, and the maximum shear force at the time of destruction was recorded, and the shear strength was calculated based on the shear force of the specimen. The test results are shown in Table 1.

[0112] Table 1 Performance test

[0113]

[0114]

[0115] 2. Organic pollutant content test

[0116] Take 5 portions of 50g of contaminated soil, mix and stir with an equal amount of water respectively, and use liquid chromatography to analyze the content of pollutants in the contaminated soil after ultrasonic dispersion for 30 minutes, and take the average value as the result; prepare solidified soil samples according to the proportions in each embodiment, and culture each solidified soil sample under conditions consistent with the use environment of the solidified soil for 30 days, take out each solidified soil sample, crush it, and then mix and stir each solidified soil sample with an equal amount of water in turn, and use liquid chromatography to analyze the content of pollutants in each solidified soil after ultrasonic dispersion for 30 minutes. The test results are shown in Table 2.

[0117] Table 2 Pollutant content test results

[0118] Experimental Group Pollutant content% Contaminated soil 1.2 Example 1 0.92 Example 2 1.12 Example 3 1.05 Example 4 0.98 Example 5 1.15 Example 6 1.13 Example 7 1.07 Comparative Example 1 1.21

[0119] It can be seen from Tables 1 and 2 that the solidified soil prepared using the composite solidifying agent provided by the present invention has compressive strength, flexural strength and shear strength that meet the standards, and the added microbial agent can decompose harmful substances in the solidified soil, thereby achieving direct utilization of contaminated soil and reducing engineering costs.

[0120] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

Claims

1. A composite curing agent, characterized in that: Including silicate cement, calcium oxide, fly ash, gypsum, chopped fibers, zeolite, microbial agents, ethylenediaminetetraacetic acid and alkyl sulfonates.

2. The composite curing agent according to claim 1, characterized in that include: 10-30 parts of Portland cement, 3-8 parts of calcium oxide, 40-60 parts of slag powder, 4-6 parts of gypsum, 1-3 parts of chopped fibers, 1-5 parts of zeolite, 1-5 parts of microbial agents, 1-10 parts of ethylenediaminetetraacetic acid and 1-10 parts of alkyl sulfonate.

3. The composite curing agent according to claim 2, characterized in that: The components of the composite curing agent include, by weight: 30 parts of silicate cement, 5 parts of calcium oxide, 50 parts of slag powder, 5 parts of gypsum, 3 parts of chopped fibers, 5 parts of zeolite, 3 parts of microbial agents, 5 parts of ethylenediaminetetraacetic acid and 5 parts of alkyl sulfonate.

4. The composite curing agent according to claim 2, characterized in that: The weight ratio of the zeolite to the microbial agent is 5:2-5:

4.

5. The composite curing agent according to claim 2, characterized in that: The weight ratio of the ethylenediaminetetraacetic acid to the alkyl sulfonate is 1:

1.

6. The composite curing agent according to claim 2, characterized in that: The length of the chopped fibers is 1-8 mm.

7. The composite curing agent according to claim 1, characterized in that: The preparation method of the composite curing agent comprises: Step S1, inoculating a microbial agent onto zeolite to obtain zeolite agent powder; Step S2, grinding calcium oxide and gypsum into powder respectively; Step S3, sieving silicate cement, fly ash, calcium oxide and gypsum for later use; Step S4, putting the sieved raw materials, zeolite inoculant powder, chopped fibers, ethylenediaminetetraacetic acid, and alkyl sulfonate into a blender in proportion and mixing them evenly to obtain a composite curing agent.

8. The composite curing agent according to claim 7, characterized in that: In step S1, the process of inoculating the microbial agent onto the zeolite to obtain the zeolite agent powder includes: Step S11, washing the zeolite with deionized water and then sterilizing it; Step S12, spraying the microbial agent on the zeolite, and drying it after curing for a preset time; Step S13, grinding and sieving the dried zeolite inoculated with the microbial agent to obtain zeolite agent powder.

9. The composite curing agent according to claim 8, characterized in that: In step S12, the curing conditions include a curing temperature of 30-35° C. and a pH value of 7-8.

10. A solidified soil prepared by using the composite solidifying agent according to any one of claims 1 to 9, characterized in that: The method for preparing the solidified soil comprises: Determine the amount of composite curing agent added based on the weight of the contaminated soil; Mix the composite curing agent and the contaminated soil according to the added amount, stir evenly and place in a mold; After curing at room temperature for a certain period of time, the cured soil is removed from the mold.

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