A method for solidification and stabilization of heavy metal solid waste

Abstract

The application discloses a solidification and stabilization method of heavy metal solid waste, which comprises the following steps: washing the heavy metal solid waste, solid-liquid separation, obtaining a first solid phase and a first clear liquid; introducing odor and flue gas into the first clear liquid for reaction, solid-liquid separation, obtaining a second solid phase, mixing the obtained first solid phase, second solid phase, medicament A and medicament B for ball milling, mixing the obtained mixture with mixing water, stirring, and shaping and curing the obtained mixture, and completing the treatment. The method can not only realize solidification and stabilization of heavy metals and harmful substances such as dioxins in fly ash, but also can realize the synergistic treatment of odor, flue gas, other aluminum-silicon-rich waste with environmental pollution risk and intermediate products formed in the treatment process, realize the 'waste treatment with waste', green and low carbon, and has the advantages of long-term stability, high strength, environmental protection, high efficiency and feasibility, and has a wide engineering application prospect.

Description

Technical Field

[0001] This invention belongs to the field of solid waste disposal technology and relates to a method for solidifying and stabilizing heavy metal solid waste. Background Technology

[0002] With urbanization and increasingly stringent environmental protection requirements, the disposal of heavy metal solid waste has become a significant social issue. For example, the incineration of municipal solid waste generates large amounts of fly ash, which contains harmful substances such as heavy metals and dioxins. This fly ash is a typical example of heavy metal-containing solid waste, and improper handling can pose a serious threat to the environment and human health. Therefore, how to safely and efficiently treat these heavy metal solid wastes (such as waste incineration fly ash) and prevent secondary pollution has become an urgent problem to be solved.

[0003] Taking waste incineration fly ash as an example, existing fly ash treatment methods mainly include cement solidification, chemical stabilization, high-temperature melting, and extraction and separation. However, cement solidification suffers from problems such as excessive leaching of heavy metals in the solidified body, low solidified body strength, poor long-term stability, poor erosion resistance in rainy environments, and large volume expansion. Chemical stabilization is hampered by high reagent costs, and the long-term stability of the solidified product is affected by various factors, hindering its widespread application. High-temperature melting is complex, requires high temperatures, and consumes a lot of energy. Extraction and separation methods suffer from high extractant costs, are ineffective when heavy metal content is low, and have limited application scope. Therefore, there is an urgent need to find a solidification and stabilization method that balances economic efficiency and environmental friendliness while maintaining long-term stability to solve the fly ash treatment and disposal problem.

[0004] Geopolymer technology, as a novel fly ash treatment technology, is attracting increasing attention from researchers due to its excellent structural stability and sustainability. However, the existing fly ash solidification and stabilization methods based on geopolymers still have the following defects: (1) The alkaline activators used are mainly one or a mixture of water glass solution and sodium hydroxide solution, which have problems such as large addition amount, high addition concentration, need to be prepared separately, high requirements for storage and transportation, and easy to cause equipment corrosion and personnel injury during use and transportation. Moreover, the raw materials of the above-mentioned alkaline activators have defects such as large environmental pollution, high energy consumption and high price in the production process, which are not conducive to large-scale promotion and application; (2) The addition ratio of auxiliary materials is too high, which leads to a reduction in the amount of fly ash added, generally between 30% and 70%, which is not conducive to improving the efficiency of fly ash treatment, making it difficult to dispose of fly ash on a large scale, and also increasing the cost of fly ash resource utilization; (3) Heavy metal stabilizers and other additives must be added, and the addition ratio is too high, which is not conducive to improving the efficiency of fly ash treatment; (4) The mixing water used is mainly tap water and recycled water, and the use of industrial wastewater (filtration liquid, leachate and concentrate, etc.) is not considered, which has the disadvantage of high treatment cost.

[0005] Therefore, obtaining a solidification and stabilization method for heavy metal solid waste that has low processing cost, high fly ash content, good solidification and stabilization effect, and combines environmental and economic benefits is of great significance for achieving effective solidification of heavy metals in heavy metal solid waste and improving the long-term stability of the solidified body. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a method for solidifying and stabilizing heavy metal solid waste that is low in processing cost, has a high fly ash content, good solidification and stabilization effect, and has both environmental and economic benefits, in order to address the shortcomings of the existing technology.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0008] A method for solidifying and stabilizing heavy metal solid waste includes the following steps:

[0009] S1. The heavy metal solid waste is washed with water and separated into solid and liquid phases to obtain the first solid phase and the first clear liquid.

[0010] S2. The odorous gas and flue gas are passed into the first clear liquid for reaction, and solid-liquid separation is performed to obtain a second solid phase and a second clear liquid; the odorous gas is a gas containing ammonia; the flue gas is a gas containing carbon dioxide;

[0011] S3. The first solid phase, the second solid phase, reagent A, and reagent B are mixed and ball-milled to obtain a mixture; reagent A is quicklime and / or hydrated lime; reagent B is an aluminum-silicon raw material;

[0012] S4. Mix the mixture with the mixing water and stir to obtain the mixture;

[0013] S5. The mixture is shaped and cured to complete the solidification and stabilization of heavy metal solid waste.

[0014] In a further improvement to the above-mentioned solidification and stabilization method, in step S2, the odorous gas is an ammonia-containing gas generated during sludge or wastewater treatment; the odorous gas is further subjected to desulfurization treatment before use; and the odorous gas flow rate is 600 L / min to 1000 L / min.

[0015] In a further improvement to the above-mentioned solidification and stabilization method, in step S2, the flue gas is industrial emission flue gas containing carbon dioxide; the industrial emission flue gas includes flue gas emitted from waste incineration plants, thermal power plants, steel plants or cement plants; the flue gas flow rate is 400L / min to 800L / min.

[0016] In a further improvement to the above-mentioned curing and stabilization method, the reaction time in step S2 is 30 min to 2 h.

[0017] In a further improvement to the above-mentioned curing and stabilization method, step S2 includes the following steps in the subsequent treatment of the second clear liquid:

[0018] (1) The second clear liquid is heated, and the ammonia gas generated is collected and refluxed into the first clear liquid;

[0019] (2) The heated second clear liquid is returned to step S1 as the eluent for washing the heavy metal solid waste.

[0020] In a further improvement to the above-mentioned solidification and stabilization method, in step S1, the heavy metal solid waste is at least one of incineration fly ash, chromium slag, thallium-containing waste slag, and smelting slag; the liquid-to-solid ratio during the water washing process is 0.5 to 1:1; the water washing is carried out under stirring conditions; the stirring speed is 400 rpm to 700 rpm; and the water washing time is 10 min to 30 min.

[0021] In a further improvement to the above-mentioned curing and stabilization method, in step S3, the amount of each raw material in the mixture, calculated as a percentage by mass, is as follows:

[0022]

[0023]

[0024] In a further improvement to the above-mentioned solidification and stabilization method, step S3 further includes the following treatment before the second solid phase is used: heating the second solid phase to decompose it into sodium carbonate and carbon dioxide, wherein the carbon dioxide is returned to the first clear liquid in step S2; the aluminum-silicon raw material includes at least one of metakaolin, dried sludge, and sorted slag; and the ball milling time is 30 min to 6 h.

[0025] In a further improvement to the above-mentioned solidification and stabilization method, in step S4, the mixing water is at least one of reclaimed water, sludge dewatering liquid, and landfill leachate membrane concentrate; the water-cement ratio is controlled to be 0.5 to 0.7:1 during the stirring process; and the stirring time is 2 to 3 minutes.

[0026] In a further improvement to the above-mentioned curing and stabilization method, step S5 involves curing the material in a mold at 30℃ to 65℃ for 6 to 24 hours, followed by demolding and curing for at least one day.

[0027] Compared with the prior art, the advantages of the present invention are as follows:

[0028] To address the shortcomings of existing geopolymer-based solidification and stabilization methods, such as poor reagent applicability, low heavy metal organic solid waste content, the need for additional heavy metal stabilizers, and high treatment costs, this invention creatively provides a solidification and stabilization method for heavy metal solid waste. First, the heavy metal solid waste is washed with water to dissolve the chloride salts (mainly sodium chloride) into the washing solution. Then, odorous gases and flue gas are introduced into the washing solution, and the ammonia in the odorous gas and the carbon dioxide in the flue gas react with the chloride salts in the washing solution, as shown in formula (1). An alkali activator raw material (sodium carbonate) is then prepared. This method synergistically treats odorous gases and flue gas while also removing chloride salts from the heavy metal solid waste, resulting in emission reduction, high treatment efficiency, resource utilization of odorous gases and flue gas, and further reducing the alkali activator effect. The preparation cost of the agent, on this basis, the heavy metal solid waste, sodium carbonate, quicklime and / or hydrated lime, and aluminum silicon raw materials are ball-milled. The physical and chemical properties of the heavy metal solid waste (such as fly ash) are induced by mechanical forces such as collision, compression, shearing and friction, thereby activating or accelerating the solid phase reaction and enhancing the reactivity of the material. At the same time, the metal components contained in the heavy metal solid waste itself and the added auxiliary materials are used as dechlorination reducing agents to achieve the degradation of toxic and harmful substances (such as dioxins) in the heavy metal solid waste. Finally, the mixture is mixed with the mixing water, and during the stirring process of adding water, sodium carbonate, quicklime and / or hydrated lime are used as alkaline activators to carry out causticization reaction, as shown in formula (2) and formula (3), to generate sodium hydroxide with high alkalinity, thereby forming a high alkaline environment, on the one hand providing and utilizing its own Ca. 2 +This process stimulates the gelling properties of the material, hydrating to generate gelling products and simultaneously promoting the transformation of these products into more stable and stronger hydrates. On the other hand, it continuously erodes the amorphous aluminosilicates in the aluminum-silicon material, forming silicon-oxygen tetrahedra [Si(OH)4] and aluminum-oxygen tetrahedra [Al(OH)4]. -As the concentration increases, monomers undergo condensation reactions, reforming Si-O-Si and Al-O-Si dimer structures, and continue to undergo condensation reactions, thereby extending the -Si-O- chains and forming a three-dimensional network cage structure. Finally, the chemical bonding and adsorption of this three-dimensional network cage structure are used to firmly seal heavy metal ions in the structure, achieving long-term fixation of heavy metal ions in heavy metal solid waste. Compared with conventional solidification and stabilization methods, this invention has the following advantages: (1) Low carbon and environmentally friendly, with no wastewater, waste residue and waste gas emissions throughout the process; (2) Sodium carbonate is prepared in situ by using the chloride salts of odor, flue gas and fly ash itself as raw materials during the production process, which synergistically treats odor and flue gas, achieving "waste treatment with waste", with emission reduction effect and high treatment efficiency; (3) The single-component alkaline activated fly ash-based polymer can be directly added with water, making the operation safer and simpler, without the need to prepare a complex alkaline activator solution; (4) Through mechanization The activation of the chemical process enhances the reaction between the heavy metal solid waste particles and the additives, increases the reactivity of the materials, reduces the amount of mixing water added, shortens the coagulation time, and can form more gel network structures, enhance the performance of the geopolymer and the solidification effect of heavy metals. It can also simultaneously degrade toxic and harmful substances (such as dioxins) in heavy metal solid waste; (5) Wastewater such as greywater, sludge dewatering liquid, and membrane concentrate can be used as alkaline activators for mixing water, which can realize the resource utilization of wastewater; (6) Heavy metal solid waste The admixture ratio is high (up to 96%), the auxiliary materials can be other industrial solid wastes, and the mixing water can be other waste liquids (sludge dewatering liquid, membrane concentrate). These waste residues and waste liquids with environmental pollution risks are treated simultaneously, realizing waste treatment with waste. The curing time is short, which significantly improves the treatment and disposal efficiency of fly ash and reduces the cost of fly ash treatment and disposal; (7) The product performance is stable, the addition amount is less than 10%, and the compressive strength of the solidified body can be adjusted according to the terminal disposal requirements; (8) The entire solidification and stabilization process of heavy metal solid waste is a carbon emission reduction process, which meets the requirements. (9) After solidification and stabilization, the heavy metal leaching concentration of the heavy metal solid waste fully meets the requirements of the "Identification of Leaching Toxicity of Hazardous Waste" (GB5085.3-2007), "Standard for Pollution Control of Municipal Solid Waste Landfill" (GB16889-2008), and "Technical Specification for Pollution Control of Municipal Solid Waste Incineration Fly Ash (Trial)" (HJ1134-2020). The heavy metal concentration should not exceed the maximum allowable emission concentration limit specified in GB8978 (the maximum allowable emission concentration of Class II pollutants shall be implemented in accordance with the Class I standard). Therefore, the solidification and stabilization method for heavy metal solid waste of the present invention has the advantages of low treatment cost, high admixture ratio, good solidification and stabilization effect, and both environmental and economic benefits. It also has the advantages of high efficiency, environmental protection, and simple operation. It can be widely used in the treatment and disposal of heavy metal solid waste, especially municipal solid waste incineration fly ash, and is suitable for large-scale engineering applications.

[0029] NH3+CO2+NaCl+H2O→NH4Cl+NaHCO3, NaHCO3→Na2CO3+CO2+H2O (1)

[0030] Ca(OH)2+Na2CO3→CaCO3+2NaOH (2)

[0031] CaO+Na2CO3+H2O→CaCO3+2NaOH (3) Attached Figure Description

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0033] Figure 1 This is a schematic diagram of the process flow for the solidification and stabilization method of heavy metal solid waste in Embodiment 1 of the present invention. Detailed Implementation

[0034] The present invention will be further described below with reference to the accompanying drawings and specific preferred embodiments, but this does not limit the scope of protection of the present invention.

[0035] The materials and instruments used in the following examples are all commercially available.

[0036] Example 1:

[0037] A method for solidifying and stabilizing heavy metal solid waste, specifically involving the treatment of municipal solid waste incineration fly ash using a modified process based on geopolymer technology, the process flow diagram of which is shown below. Figure 1 As shown, it includes the following steps:

[0038] (1) With a liquid-to-solid ratio of 0.5 ml / g, the fly ash was washed with water at 595 rpm for 10 min. After the water washing was completed, the fly ash was dehydrated to obtain the first solid phase and the first clear liquid.

[0039] (2) 600 L / min of desulfurization odor gas and incineration flue gas are introduced into the first clear liquid, reacted for 30 min, dehydrated, and the second solid phase and the second clear liquid are obtained. The subsequent treatment of the second clear liquid includes: heating the second clear liquid with the residual heat of the incineration flue gas to decompose ammonium chloride into ammonia, which is then returned to the first clear liquid as raw material. The heated second clear liquid is reused as an eluent in step (1) and used to wash fly ash with water. The subsequent treatment of the second solid phase includes: heating the second solid phase with the residual heat of the incineration flue gas to decompose it into sodium carbonate and carbon dioxide. Carbon dioxide is returned to the first clear liquid as raw material, and sodium carbonate is used as an alkaline activator in the next step.

[0040] (3) The raw material formula is based on the following weight percentages: alkaline activator equivalent of 1% (calculated as sodium hydroxide, i.e., 0.925% quicklime and 1.325% sodium carbonate), fly ash 95%, metakaolin 5%. After accurately weighing the quicklime, the generated sodium carbonate, the first solid phase (fly ash after water washing) and metakaolin (aluminum-silicon raw material), they are placed in a planetary ball mill for ball milling and mixing for 5 hours to form a single-component solid mixture (precursor).

[0041] (4) Add mixing water to the mixing tank in step (3) according to a water-to-binder ratio of 0.7:1. The mixing water is medium water. Continue to stir rapidly for 2 min to 3 min to form a solid-liquid mixture (slurry).

[0042] (5) Pour the solid-liquid mixture into the mold and place the mold on the vibrating table to compact it. Seal the solidified body in the mold and cure it at 50°C for 12 hours. Demold it and then place it at room temperature for curing for 3 days to complete the solidification and stabilization treatment of fly ash.

[0043] Tests showed that the cured fly ash solidified body had a moisture content of less than 30%, a compressive strength of ≥2.7 MPa, and the dosage of alkaline activator and auxiliary materials was less than 10% of the fly ash mass. The leaching concentration of harmful substances was determined according to the following standards: "Solid Waste Leaching Toxicity Leaching Method - Sulfuric Acid and Nitric Acid Method" (HJ / T299-2007), "Solid Waste Leaching Toxicity Leaching Method - Acetic Acid Buffer Solution Method" (HJ / T300-2007), and "Solid Waste Leaching Toxicity Leaching Method - Horizontal Oscillation Method" (HJ / T557-2008). 10) Conduct inspections to ensure that the heavy metal concentrations meet the requirements of the "Identification of Leaching Toxicity of Hazardous Waste" (GB5085.3-2007), "Standard for Pollution Control of Municipal Solid Waste Landfill" (GB16889-2008), and "Technical Specification for Pollution Control of Fly Ash from Municipal Solid Waste Incineration (Trial)" (HJ1134-2020), respectively. The heavy metal concentrations should not exceed the maximum allowable emission concentration limits specified in GB8978 (the maximum allowable emission concentration for Class II pollutants shall be implemented according to the Class I standard), as shown in Table 1. Table 1 shows that after curing, the solidified body, using the three national standard methods for determining heavy metal leaching concentration, all show heavy metal leaching concentrations that meet the corresponding national standard limits for their respective methods.

[0044] Table 1. Leaching concentrations and emission limits of solidified heavy metals (unit: mg / L)

[0045] Be 0.0001 5 0.00003L 0.02 0.0235 0.02 Cr 0.0113 1.5 0.0534 15 0.0071 4.5 Ni 0.00003L 1 0.00003L 5 ND 0.5 Cu 0.0044 5 0.00001L 100 ND 40 Zn 0.0002L 2 0.0002L 100 0.0033 100 As 0.0008 0.5 0.0001L 5 0.0044 0.3 Se 0.0043 / 0.0097 1 0.00042 0.1 Cd 0.0001 0.1 0.00003L 1 0.00045 0.15 Ba 0.116 / 1.36 100 0.0018 25 Hg 0.0057 0.05 0.0004 0.1 0.0082 0.05 Pb 0.0002 1 0.233 5 0.0235 0.25

[0046] In addition, the leaching concentration of heavy metals in the fly ash solidified body under different curing time conditions was tested, and the results are shown in Table 2. As can be seen from Table 2, when the curing time of the solidified body is ≥24h, the leaching concentration of heavy metals in the solidified body meets the requirements of the "Standard for Pollution Control of Municipal Solid Waste Landfill" (GB16889-2008).

[0047] Table 2. Leaching concentrations and emission limits of heavy metals in solidified bodies under different curing times (unit: mg / L)

[0048] Be ND 0.00045 0.00005 0.00022 0.02 Cr 0.039 0.045 0.0496 0.046 4.5 Ni 0.001 ND 0.0019 0.0013 0.5 Cu 0.0039 0.0063 0.003 0.0076 40 Zn ND 0.05 [[ID= ​ 100 ​ 0.0036 0.001 0.0035 0.004 0.3 ​ 0.0088 0.0082 0.0085 0.0072 0.1 ​ 0.00045 0.00036 0.0005 0.00037 0.15 ​ 2.98 1.45 1.88 1.75 25 ​ 0.0019 0.0009 0.0054 0.017 0.05 ​ 0.0467 0.0262 0.0088 0.0155 0.25

[0049] Example 2:

[0050] A method for solidifying and stabilizing heavy metal solid waste is basically the same as that in Example 1, except that the mixing water used in Example 2 is sludge dewatering liquid.

[0051] In addition, the leaching concentration of heavy metals in the fly ash solidified body was tested, and the results are shown in Table 3. As can be seen from Table 3, when sludge dewatering liquid is used as mixing water, the heavy metal leaching meets the requirements of the "Standard for Pollution Control of Municipal Solid Waste Landfill" (GB16889-2008).

[0052] Table 3. Leaching concentrations and emission limits of heavy metals in solidified bodies (unit: mg / L)

[0053] ​ ​ 0.02 Cr 0.0839 4.5 ​ 0.0183 0.5 ​ 0.848 40 ​ ​ 100 ​ 0.0217 0.3 ​ 0.0097 0.1 ​ 0.00059 0.15 ​ 2.10 25 ​ 0.0104 0.05 ​ 0.0231 0.25

[0054] Example 3:

[0055] A method for solidifying and stabilizing heavy metal solid waste is basically the same as that in Example 1, except that the mixing water used in Example 3 is landfill leachate membrane concentrate.

[0056] In addition, the leaching concentration of heavy metals in the fly ash solidified body was tested, and the results are shown in Table 4. As can be seen from Table 4, when landfill leachate membrane concentrate is used as mixing water, the leaching concentration of heavy metals in the solidified body meets the requirements of the "Standard for Pollution Control of Municipal Solid Waste Landfill" (GB16889-2008), which has a synergistic treatment and disposal effect.

[0057] Table 4. Leaching concentrations and emission limits of heavy metals in solidified bodies (unit: mg / L)

[0058]

[0059]

[0060] The results above demonstrate that the method of this invention not only achieves the solidification and stabilization of harmful substances such as heavy metals and dioxins in fly ash, thus reducing the harm of alkaline activators to the environment and human health during operation, but also significantly improves the treatment efficiency of fly ash from municipal solid waste incineration. Simultaneously, it can synergistically treat odors, flue gas, other aluminum-silicon-rich wastes with environmental pollution risks, and intermediate products formed during the treatment process, achieving "waste treatment with waste," a green and low-carbon approach. Furthermore, the method of this invention has advantages such as long-term stability, high strength, environmental friendliness, high efficiency, and feasibility, effectively solving the problems existing in the prior art and possessing broad prospects for engineering applications.

[0061] The above embodiments are merely preferred embodiments of the present invention, and the scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A method for solidifying and stabilizing heavy metal solid waste, characterized in that, Includes the following steps: S1. The heavy metal solid waste is washed with water and separated into solid and liquid phases to obtain the first solid phase and the first clear liquid. S2. The odorous gas and flue gas are passed into the first clear liquid for reaction, followed by solid-liquid separation to obtain a second solid phase and a second clear liquid; the reaction time is 30 min to 2 h; the flow rate of the odorous gas is 600 L / min to 1000 L / min; the odorous gas is a gas containing ammonia; the flow rate of the flue gas is 400 L / min to 800 L / min; the flue gas is a gas containing carbon dioxide. S3. The first solid phase, the second solid phase, reagent A, and reagent B are mixed and ball-milled to obtain a mixture; the ball milling time is 5-6 hours; reagent A is quicklime and / or hydrated lime; reagent B is an aluminum-silicon raw material; the aluminum-silicon raw material includes at least one of metakaolin, dried sludge, and sorting slag; the amount of each raw material in the mixture, by mass percentage, is as follows: The first solid phase is 90%–96%. The second solid phase comprises 1.325%–10.7%. Agent A: 0.925%–7.4% Drug B 4%–10%; S4. Mix the mixture with the mixing water and stir to obtain a mixture; during the stirring process, control the water-cement ratio to be 0.5-0.7:1; the stirring time is 2-3 minutes. S5. The mixture is shaped and cured to complete the solidification and stabilization of heavy metal solid waste.

2. The curing and stabilization method according to claim 1, characterized in that, In step S2, the odorous gas is an ammonia-containing gas generated during sludge or sewage treatment; before use, the odorous gas is further subjected to desulfurization treatment.

3. The curing and stabilization method according to claim 2, characterized in that, In step S2, the flue gas is industrial emission flue gas containing carbon dioxide; the industrial emission flue gas includes flue gas emitted from waste incineration plants, thermal power plants, steel plants or cement plants.

4. The curing and stabilization method according to claim 1, characterized in that, In step S2, the subsequent processing of the second clear liquid includes the following steps: (1) The second clear liquid is heated, and the ammonia gas generated is collected and refluxed into the first clear liquid; (2) The heated second clear liquid is returned to step S1 as the eluent for washing the heavy metal solid waste.

5. The curing and stabilization method according to any one of claims 1 to 4, characterized in that, In step S1, the heavy metal solid waste is at least one of incineration fly ash, chromium slag, thallium-containing waste slag, and smelting slag; the liquid-to-solid ratio during the water washing process is 0.5 to 1:1; the water washing is carried out under stirring conditions; the stirring speed is 400 rpm to 700 rpm; and the water washing time is 10 min to 30 min.

6. The curing and stabilization method according to any one of claims 1 to 4, characterized in that, In step S3, the second solid phase is further treated as follows before use: the second solid phase is heated to decompose into sodium carbonate and carbon dioxide, and the carbon dioxide is returned to the first clear liquid in step S2.

7. The curing and stabilization method according to any one of claims 1 to 4, characterized in that, In step S4, the mixing water is at least one of reclaimed water, sludge dewatering liquid, and landfill leachate membrane concentrate.

8. The curing and stabilization method according to any one of claims 1 to 4, characterized in that, In step S5, the curing process involves curing in a mold at 30℃ to 65℃ for 6 to 24 hours, followed by demolding, and curing for at least 1 day.

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