Heavy metal solidifying agent and method for solidifying and repairing heavy metal contaminated soil

Abstract

The application discloses a heavy metal solidifying agent and a method for solidifying and repairing heavy metal contaminated soil. The heavy metal solidifying agent comprises the following components in parts by mass: lithium slag-based cementing material 50-80 parts, blast furnace slag 5-30 parts, biochar 5-30 parts, and calcium lignosulfonate 1-10 parts. The heavy metal solidifying agent formula of the application takes industrial solid waste, agricultural and forestry solid waste and industrial by-products as core raw materials, realizes efficient utilization of solid waste resources, and achieves the environmental protection goal of 'waste treatment with waste'. The solidifying agent formula has excellent long-term solidifying effect on heavy metals and excellent compressive strength of the solidified body. Compared with traditional solidifying agents, the application is green and environmentally friendly, can realize efficient utilization of solid waste resources, has mild and suitable pH control, good environmental compatibility, low raw material cost, outstanding comprehensive economy, and excellent solidifying and stabilizing effect, green and low-carbon properties and engineering popularization value.

Description

Technical Field

[0001] This invention relates to the field of solidification treatment of heavy metal contaminated soil and solid waste recycling, specifically to a heavy metal solidification agent and a method for solidifying and remediating heavy metal contaminated soil. Background Technology

[0002] If heavy metal pollutants in soil are not effectively controlled, they will accumulate through the food chain, posing a continuous threat to the balance of the ecosystem and human health. Current technologies for treating heavy metal pollution in soil generally suffer from high treatment costs and are prone to causing secondary pollution, making them unsuitable for the practical needs of large-scale soil remediation. Therefore, the development of efficient and environmentally friendly solidification and stabilization technologies is urgently needed. These technologies can utilize the hydration reaction and adsorption properties of materials to transform easily migrating free heavy metal ions in the soil into stable crystalline or complexed states, blocking their migration and diffusion pathways, and ultimately achieving the harmless treatment of heavy metal pollution in soil. Lithium slag-based cementitious materials, as green cementitious materials prepared from industrial solid waste, possess the dual advantages of excellent hydration activity and low preparation cost. Their hydration products can effectively fix heavy metal ions in the soil through multiple processes such as physical encapsulation, chemical adsorption, and ion exchange, providing a high-quality material carrier and feasible technical solution for the remediation of heavy metal pollution in soil.

[0003] Currently, the mainstream technologies for solidification treatment of heavy metal pollution in soil mainly include cement-based solidification, lime solidification, and chemical agent solidification. Several related patents have been published, but all have significant shortcomings and cannot meet the needs for efficient, environmentally friendly, and long-term remediation. Chinese patent CN111040770A, "A Composite Acidic Soil Conditioner Rich in Carbonates and Organic Anions and Its Preparation Method and Application," uses carbonates and organic anions as core components to form a conditioner. While it can adjust the pH of acidic soil and achieve preliminary fixation of heavy metals such as lead, cadmium, and arsenic, making it suitable for acidic soil remediation scenarios, this patent does not introduce a gelling component, failing to form a dense solidification framework. It relies solely on chemical precipitation to fix heavy metals, resulting in limited fixation effectiveness. Furthermore, organic anions are easily decomposed by soil microorganisms, leading to a high risk of heavy metal leaching in the later stages. Chinese patent CN 121248191 A, entitled "A High-Efficiency Solidification and Stabilization Agent for Lithium Slag and Its Preparation Method," uses lithium slag, carbide slag, and nano-silicates as raw materials. While it achieves resource utilization of lithium slag, it does not introduce highly efficient adsorption components and relies solely on the physical encapsulation of the gel products to fix heavy metals. This results in poor adsorption and fixation effects for low-concentration heavy metals, and it does not consider the synergistic effect of the components, leading to limited strength and long-term stability of the solidified body. Chinese patent CN119874235A, entitled "A Solid Waste-Based Impermeable Material and Its Preparation Method and Application," uses coal gangue, lithium slag, and blast furnace slag as raw materials to prepare impermeable materials, focusing on improving impermeability. While it can reduce the risk of heavy metal leaching, this patent has a narrow scope of application, only suitable for impermeable treatment of lithium slag dumps, and difficult to adapt to the remediation of various types of heavy metal-contaminated soils such as ordinary farmland and industrial sites. In addition, traditional cement curing patents have problems such as easy cracking of the cured body in the later stage and poor long-term fixation effect on some heavy metals; lime curing patents have defects such as insufficient stability of the cured product and risk of secondary pollution; and chemical agent curing patents have problems such as toxicity of chemical agents and poor compatibility.

[0004] Based on the shortcomings of the existing technologies, there is an urgent need in this field to develop a green, environmentally friendly, widely adaptable, and long-term stable curing material. This material should also have the advantages of high compressive strength of the cured body, low repair cost, and no risk of secondary pollution, so as to solve many pain points of the existing curing technologies. Summary of the Invention

[0005] To overcome the shortcomings of the prior art, this invention provides a heavy metal curing agent made from smelting waste generated during lithium extraction. This heavy metal curing agent comprises: a main curing agent: lithium slag-based cementitious material; an inorganic curing agent: blast furnace slag; and organic curing agents: calcium lignosulfonate and biochar. This curing agent formulation exhibits excellent long-term curing effect on heavy metals, and the resulting cured body demonstrates excellent compressive strength.

[0006] The first aspect of this invention provides a heavy metal curing agent, which, by weight, comprises the following components:

[0007] 50-80 parts lithium slag-based cementitious material, 5-30 parts blast furnace slag, 5-30 parts biochar, and 1-10 parts calcium lignosulfonate.

[0008] The heavy metal solidification agent of this invention uses four types of solid waste that urgently need to be disposed of on a large scale as main raw materials: lithium slag-based cementitious materials (byproducts of lithium smelting), blast furnace slag (byproducts of the metallurgical industry), biochar (pyrolysis products of agricultural and forestry waste), and calcium lignosulfonate (extraction products of pulping black liquor). It can achieve "treating waste with waste and turning waste into treasure", which meets the needs of green, circular and low-carbon development. At the same time, it has the advantages of low cost, environmental friendliness and stable solidification effect. It can effectively make up for the shortcomings of existing technologies and provide a feasible path for the long-term remediation of soil heavy metal pollution.

[0009] Lithium slag, a major industrial solid waste generated by the lithium smelting industry, not only occupies a large amount of land resources when dumped and disposed of, but also easily causes environmental pollution problems such as dust and leachate. Therefore, the resource utilization of lithium slag has significant environmental and economic value. Preparing lithium slag into lithium slag-based cementitious materials for use as soil heavy metal solidification agents has significant technical advantages: compared with traditional cement and lime solidification agents, lithium slag-based cementitious materials can achieve the secondary utilization of industrial solid waste, significantly reducing the preparation and remediation costs of solidification materials; its production process requires no high-temperature calcination or only low-temperature treatment, resulting in significantly lower carbon emissions than traditional cement systems, meeting the needs of green and low-carbon development; simultaneously, the compounding of blast furnace slag, biochar, and calcium lignosulfonate minimizes disturbance to soil pH, avoiding problems such as soil compaction and ecological damage caused by drastic changes in soil pH, and effectively improves the compressive strength and structural integrity of the solidified body, enhancing the long-term fixation effect of heavy metals. It is suitable for various complex types of heavy metal contaminated soils, effectively compensating for the shortcomings of existing solidification technologies, and providing a feasible path for the long-term, green, and low-cost remediation of soil heavy metal pollution.

[0010] Preferably, the heavy metal curing agent comprises the following components: 55-70 parts of lithium slag-based cementitious material, 10-25 parts of blast furnace slag, 10-25 parts of biochar, and 3-5 parts of calcium lignosulfonate.

[0011] Preferably, the chemical composition of the lithium slag-based cementitious material includes: 24-26wt% SiO2, 12-13wt% Al2O3, 1-1.5wt% Fe2O3, 1-1.2wt% K2O, 4-5wt% MgO, 0.7-0.9wt% TiO2, 35-40wt% CaO, 0.2-0.4wt% Na2O, and 0.4-0.6wt% MnO.

[0012] Preferably, the chemical composition of the blast furnace slag includes: 23-25wt% SiO2, 11-13wt% Al2O3, 0.2-0.4wt% Fe2O3, 0.2-0.4wt% K2O, 1.2-1.4wt% TiO2, 35-40wt% CaO, 0.4-0.6wt% Na2O, and 0.2-0.4wt% MnO.

[0013] Preferably, the biochar has a particle size of 150-250 mesh.

[0014] Preferably, the biochar is prepared by pyrolyzing agricultural and forestry waste at 700-900℃ for 2-4 hours, then activating it with steam and crushing it.

[0015] The second aspect of the present invention provides a method for solidifying and remediating heavy metal contaminated soil, comprising the following steps: mixing the components of the heavy metal solidifying agent with the heavy metal contaminated soil and adding water, stirring, sealing and curing, thereby solidifying the heavy metal contaminated soil.

[0016] Preferably, the heavy metal contaminated soil is copper and / or zinc contaminated soil.

[0017] Preferably, the mass ratio of the heavy metal contaminated soil to the heavy metal solidification agent is (85%–95%): (5%–15%).

[0018] Compared with the prior art, the beneficial effects of the present invention are:

[0019] The heavy metal curing agent formulation of this invention uses industrial solid waste, agricultural and forestry solid waste, and industrial by-products as core raw materials to achieve efficient resource utilization of solid waste and realize the environmental protection goal of "treating waste with waste". This curing agent formulation exhibits excellent long-term curing effect on heavy metals, and the resulting solidified body has excellent compressive strength. Compared with traditional curing agents, this invention is green and environmentally friendly, enabling efficient resource utilization of all solid waste. The system has a mild and suitable pH control, good environmental compatibility, low raw material cost, and outstanding overall economic efficiency. It also possesses excellent curing and stabilization effects, green and low-carbon attributes, and engineering promotion value.

[0020] The heavy metal solidification system of this invention is not a simple superposition of components, but rather achieves efficient and stable solidification through multi-level synergistic effects among lithium slag-based cementitious materials, blast furnace slag, calcium lignosulfonate, and biochar. The lithium slag-based cementitious material acts as the main solidifying agent, hydrating to generate a CSH / CAH three-dimensional framework, which initially fixes heavy metals through physical encapsulation and ion exchange. The blast furnace slag, as an inorganic auxiliary component, undergoes secondary hydration of its active silica and aluminum under the activation of Ca(OH)2, a product of lithium slag hydration, supplementing the cementitious products and optimizing the solidified body structure. While using lithium slag-based cementitious materials alone can achieve higher compressive strength, it also leads to a sharp increase in the system's pH value. An excessively alkaline environment can easily cause changes in the soil's physicochemical properties and disrupt the microbial community structure, failing to meet long-term environmental safety requirements. Using blast furnace slag alone results in low hydration levels. Calcium lignosulfonate, with its surface activity, improves the dispersibility of solid particles and optimizes the organic-inorganic interface compatibility by bonding and complexing with the cemented phase and heavy metal ions through active groups on its molecular chains. Simultaneously, calcium lignosulfonate can effectively regulate the hydration process of the system, avoiding excessive alkalization. Biochar, with its ultra-large specific surface area (1000 m²),... 2 The biochar, rich in oxygen-containing functional groups and containing high specific surface area (above g), efficiently captures free heavy metals through microporous retention, physical adsorption, and chemical chelation, further buffering the pH of the system and synergistically maintaining the pH environment of the solidified body with calcium lignosulfonate. Simultaneously, the fine-particle component of the high specific surface area biochar fills the large pores between soil particles, optimizing soil porosity without altering the overall dry density. This reduces harmful large pores in the soil, lowering the risk of pore collapse during compression. The fine-particle filling significantly increases the contact area between soil particles and biochar particles, enhancing interparticle bonding and thus significantly improving unconfined compressive strength. The four components work together to form a multi-mechanism system of "physical sealing-chemical precipitation-interfacial complexation-microporous adsorption-pH regulation," ultimately constructing a solidification system with high mechanical strength, low heavy metal leaching, and long-term environmental stability. This achieves synergistic optimization of mechanical properties, solidification effect, and environmental safety, solving the technical problems of excessively high pH and insufficient long-term stability when using lithium slag-based cementitious materials alone, while also promoting the large-scale utilization of lithium slag. Detailed Implementation

[0021] The specific embodiments of the present invention will be further described below. It should be noted that these descriptions are for the purpose of aiding understanding the present invention, but do not constitute a limitation thereof. Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0022] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods, and the experimental materials used in the following embodiments are all available through conventional commercial channels.

[0023] The lithium slag-based cementitious material and blast furnace slag used in the following examples are both industrial by-products, and their main chemical compositions are shown in Table 1:

[0024] Table 1. Main chemical composition of lithium slag-based cementitious materials and blast furnace slag

[0025]

[0026] The biochar described in this invention is a byproduct of agricultural solid waste. This invention does not limit the specific agricultural solid waste used to prepare biochar; it can be straw, corn cobs, peanut shells, etc., nor does it limit the specific pyrolysis conditions. In the following examples, the biochar was obtained by pyrolyzing corn straw at 700-900℃ for 2-4 hours, followed by steam activation and pulverization through a 200-mesh sieve.

[0027] The calcium lignosulfonate described in the following examples is a byproduct of papermaking black liquor, containing 38wt% to 42wt% carbon and 4wt% to 6wt% sulfur, and is commercially available.

[0028] Example 1

[0029] This embodiment provides a heavy metal curing agent, the components of which are: 60 parts of lithium slag-based cementitious material, 18 parts of blast furnace slag, 18 parts of biochar, and 4 parts of calcium lignosulfonate. The heavy metal curing agent is obtained by mixing the components.

[0030] This embodiment also provides a method for solidifying heavy metals, which uses the aforementioned heavy metal solidifying agent to solidify 5000 mg / kg copper-contaminated soil provided in this embodiment, specifically including the following steps:

[0031] 1) Mix the solidifying agent with the heavy metal contaminated soil at room temperature to obtain a mixture, wherein the mass percentages of the heavy metal contaminated soil and the solidifying agent are 95% and 5%, respectively;

[0032] 2) Add water to the mixture obtained in step 1) to make the mixture reach the optimum soil moisture content: 14.0% to 16.0%;

[0033] 3) Stir the above mixture after adding water evenly, seal and simmer for 24 hours, compact into specimens of φ39.1 mm × 80 mm, and cure for 7 days under standard curing conditions {(20±2)℃, relative humidity ≥95%};

[0034] 4) Analyze the unconfined compressive strength of the specimens, the leaching concentration of copper, and the pH of the solidified soil.

[0035] After the samples were leached with toxic substances, they were digested using a microwave digester, and the concentration of heavy metals in the digestion solution was determined by atomic absorption spectrophotometry.

[0036] Example 2

[0037] The difference between this embodiment and Example 1 is that the amount of each component of the curing agent is different. The proportion of each component of the curing agent in this embodiment is: 65 parts of lithium slag-based cementitious material, 16 parts of blast furnace slag, 16 parts of biochar and 3 parts of calcium lignosulfonate; all other process steps and process parameters are the same as in Example 1.

[0038] Example 3

[0039] The difference between this embodiment and Example 1 is that the amount of each component of the curing agent is different. The proportion of each component of the curing agent in this embodiment is: 70 parts of lithium slag-based cementitious material, 13 parts of blast furnace slag, 12 parts of biochar and 5 parts of calcium lignosulfonate; all other process steps and process parameters are the same as in Example 1.

[0040] Example 4

[0041] The difference between this embodiment and Example 1 is that the amount of each component of the curing agent is different. The proportion of each component of the curing agent in this embodiment is: 55 parts of lithium slag-based cementitious material, 21 parts of blast furnace slag, 20 parts of biochar and 4 parts of calcium lignosulfonate; all other process steps and process parameters are the same as in Example 1.

[0042] Example 5

[0043] The difference between this embodiment and Example 1 is that the heavy metal in the contaminated soil is zinc at a concentration of 5000 mg / kg; all other process steps, process parameters, and raw material additions are the same as in Example 1.

[0044] Comparative Example 1

[0045] The difference between this comparative example and Example 1 is that the main cementing material in the curing agent is cement. The components of the curing agent in this comparative example are: 60 parts of 32.5 grade cement, 18 parts of blast furnace slag, 18 parts of biochar, and 4 parts of calcium lignosulfonate. All other process steps and process parameters are the same as in Example 1.

[0046] Comparative Example 2

[0047] The difference between Comparative Example 2 and Example 2 is that the main cementing material in the curing agent is cement. The components of the curing agent in this comparative example are: 65 parts of 32.5 grade cement, 16 parts of blast furnace slag, 16 parts of biochar and 3 parts of calcium lignosulfonate; all other process steps and process parameters are the same as in Example 2.

[0048] Comparative Example 3

[0049] The difference between Comparative Example 3 and Example 3 is that the main cementing material in the curing agent is cement. The components of the curing agent in this comparative example are: 70 parts of 32.5 grade cement, 13 parts of blast furnace slag, 12 parts of biochar and 5 parts of calcium lignosulfonate; all other process steps and process parameters are the same as in Example 3.

[0050] Comparative Example 4

[0051] The difference between these four comparative examples and Example 3 is that the amounts of each component of the curing agent are different and the formula does not contain calcium lignosulfonate. The components of the curing agent in this comparative example are: 70 parts of lithium slag-based cementitious material, 15 parts of blast furnace slag, 15 parts of biochar and 0 parts of calcium lignosulfonate; all other process steps and process parameters are the same as in Example 3.

[0052] Comparative Example 5

[0053] The difference between these 5 comparative examples and Example 3 is that the amounts of each component of the curing agent are different and the formula does not contain biochar. The components of the curing agent in this comparative example are: 70 parts of lithium slag-based cementitious material, 25 parts of blast furnace slag, 0 parts of biochar and 5 parts of calcium lignosulfonate; all other process steps and process parameters are the same as in Example 3.

[0054] Comparative Example 6

[0055] The difference between this comparative example 6 and Example 3 is that the amount of each component of the curing agent is different and the formula does not contain blast furnace slag. The components of the curing agent in this comparative example are: 70 parts of lithium slag-based cementitious material, 0 parts of blast furnace slag, 25 parts of biochar and 5 parts of calcium lignosulfonate; all other process steps and process parameters are the same as in Example 3.

[0056] Comparative Example 7

[0057] The curing agent used in Comparative Example 7 was 100 parts of lithium slag-based cementitious material, and all other components were 0 parts each.

[0058] The solidifying agent was then used to solidify the 5000 mg / kg copper-contaminated soil provided in this comparative example, including the following steps:

[0059] 1) Mix the solidifying agent with the heavy metal contaminated soil at room temperature to obtain a mixture, wherein the mass percentages of the heavy metal contaminated soil and the solidifying agent are 95% and 5%, respectively;

[0060] 2) Add water to the mixture obtained in step 1) to make the mixture reach the optimum soil moisture content;

[0061] 3) After mixing the above mixture with added water evenly, seal and simmer for 24 hours, compact it into soil specimens with a diameter of φ39.1 mm × 80 mm, and cure for 7 days under standard curing conditions {(20±2)℃, relative humidity ≥95%};

[0062] 4) Analyze the unconfined compressive strength of the specimens, the leaching concentration of copper, and the pH of the solidified soil.

[0063] Comparative Example 8

[0064] The curing agent used in Comparative Example 8 was 100 parts of blast furnace slag, and all other components were 0 parts each; all other process steps and process parameters were the same as those in Comparative Example 7.

[0065] Comparative Example 9

[0066] In Comparative Example 9, the curing agent used was 100 parts of biochar, and all other components were 0 parts each; all other process steps and parameters were the same as in Comparative Example 7.

[0067] Comparative Example 10

[0068] The curing agent used in Comparative Example 10 was 100 parts of calcium lignosulfonate, and all other components were 0 parts each; all other process steps and process parameters were the same as those in Comparative Example 7.

[0069] The amount of curing agent added in the above embodiments and comparative examples is shown in Table 2.

[0070] Table 2 Curing agent addition amount

[0071]

[0072] In the above examples and comparative examples, the heavy metal contaminated soil contained a single heavy metal pollutant, namely copper or zinc. The test results before solidification, Examples 1-5, and Comparative Examples 1-10 were evaluated according to the standards "Identification Standard for Hazardous Waste - Leaching Toxicity Identification" (GB5085.3-2007) and "Standard for Soil Remediation of Heavy Metal Contaminated Sites" (DB43 / T1165-2016), and the CRITIC weighting method was used for comprehensive evaluation. The unconfined compressive strength, heavy metal leaching concentration, soil pH, and comprehensive score results are shown in Table 3.

[0073] Table 3 Comparison of Unconfined Compressive Strength, Heavy Metal Leaching Concentration, pH and Comprehensive Indicators

[0074]

[0075] As shown in Table 3, the heavy metal leaching concentrations in the above embodiments are very low. According to the national standard "Identification Standard for Hazardous Waste - Leaching Toxicity Identification" (GB 5085.3-2007), the leaching concentration limit for copper and zinc is 100 mg / L. The heavy metal leaching concentrations corresponding to the curing agent formulations in the embodiments are all far below this standard limit, meeting the leaching toxicity identification requirements. According to the national standard "Surface Water Environmental Quality Standard" (GB3838-2002), the Class II basic item standard limit for surface water environmental quality standards requires copper ≤ 1.0 mg / L and zinc ≤ 1.0 mg / L. mg / L, the heavy metal leaching concentration corresponding to the solidifying agent formulation in the examples meets the standard limit and satisfies the surface water environmental quality requirements; according to the "Standard for Soil Remediation of Heavy Metal Contaminated Sites" (DB43 / T1165-2016), the pH standard for soil remediation of heavy metal contaminated sites is 6.0-9.0, and cement replacing lithium slag-based cementitious materials all exceed the standard limit (Comparative Examples 1-3); when using single lithium slag-based cementitious materials (Comparative Example 7), blast furnace slag (Comparative Example 8), biochar (Comparative Example 9), or calcium lignosulfonate (Comparative Example 10), there are problems such as excessively high pH, ​​low unconfined compressive strength, excessively high leaching concentration, or excessively low pH; the comprehensive scores of Comparative Examples 4-6 are all lower than those of Example 3; in addition, in Examples 1-4 for copper contaminated soil, the unconfined compressive strength of the soil after 7 days of solidification is ≫ 350 The pH value of the soil treated with the composite solidifying agent was <8.10 under low dosage (5%) conditions, which avoided the damage to the soil's physical and chemical properties and microbial community structure caused by the overly alkaline environment, reduced soil compaction and nutrient loss, and ensured the feasibility of the soil for various subsequent use scenarios such as greening, reclamation, and site backfilling. It achieved the dual goals of heavy metal solidification and stabilization and soil physical and chemical property protection.

[0076] The embodiments of the present invention have been described in detail above, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and these variations still fall within the protection scope of the present invention.

Claims

1. A heavy metal curing agent, characterized in that, The heavy metal curing agent comprises the following components by weight: 50-80 parts lithium slag-based cementitious material, 5-30 parts blast furnace slag, 5-30 parts biochar, and 1-10 parts calcium lignosulfonate.

2. The heavy metal curing agent according to claim 1, characterized in that, The heavy metal curing agent comprises the following components: The mixture consists of 55-70 parts lithium slag-based cementitious material, 10-25 parts blast furnace slag, 10-25 parts biochar, and 3-5 parts calcium lignosulfonate.

3. The heavy metal curing agent according to claim 1, characterized in that, The chemical composition of the lithium slag-based cementitious material includes: 24-26wt% SiO2, 12-13wt% Al2O3, 1-1.5wt% Fe2O3, 1-1.2wt% K2O, 4-5wt% MgO, 0.7-0.9wt% TiO2, 35-40wt% CaO, 0.2-0.4wt% Na2O, and 0.4-0.6wt% MnO.

4. The heavy metal curing agent according to claim 1, characterized in that, The chemical composition of the blast furnace slag includes: 23-25wt% SiO2, 11-13wt% Al2O3, 0.2-0.4wt% Fe2O3, 0.2-0.4wt% K2O, 1.2-1.4wt% TiO2, 35-40wt% CaO, 0.4-0.6wt% Na2O, and 0.2-0.4wt% MnO.

5. The heavy metal curing agent according to claim 1, characterized in that, The biochar has a particle size of 150-250 mesh.

6. The heavy metal curing agent according to claim 5, characterized in that, The biochar is prepared by pyrolyzing agricultural and forestry waste at 600-1000℃ for 0.5-5 hours, then activating it with steam and crushing it.

7. A method for solidifying and remediating heavy metal-contaminated soil, characterized in that, The process includes the following steps: mixing the components of the heavy metal solidifying agent described in claims 1-6 with heavy metal contaminated soil, adding water, stirring, sealing and curing the mixture to achieve solidification of the heavy metal contaminated soil.

8. The method for solidifying and remediating heavy metal contaminated soil according to claim 7, characterized in that, The heavy metal contaminated soil is copper and / or zinc contaminated soil.

9. The method for solidifying and remediating heavy metal contaminated soil according to claim 7, characterized in that, The mass ratio of the heavy metal contaminated soil to the heavy metal solidification agent is (85%–95%): (5%–15%).

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