Resource utilization method of electroplating sludge

Abstract

The invention relates to the technical field of electroplating sludge utilization, and discloses an electroplating sludge resource utilization method, which adopts a mechanical dehydration mode, such as utilizing equipment such as a plate-and-frame filter press or a centrifugal machine, to promote water separation in electroplating sludge by virtue of mechanical pressure, or adopts a hot drying means to accelerate water evaporation through a specific temperature environment, so that the electroplating sludge is recycled. The water content of the electroplating sludge is reduced to 50% or below in a full-force mode, and the electroplating sludge subjected to dewatering operation needs to be treated by means of crushing equipment. According to the electroplating sludge resource utilization method, heavy metals such as copper and nickel which are urgently needed in electronics and new energy industries are efficiently recycled from the electroplating sludge with complex components, compared with a traditional simple physical treatment method, the extraction purity is greatly improved, high-quality metal raw materials can be directly provided for related industries, dependence on primary mineral resources is effectively relieved, and the method is suitable for industrial production. Energy consumption and ecological damage in the mining process are reduced, metal resources in the market are supplemented with low cost, and sustainable development of the industry is promoted.

Description

Technical Field

[0001] The invention relates to the technical field of electroplating sludge utilization, in particular to a method for resource utilization of electroplating sludge. Background Art

[0002] Electroplating sludge is a hazardous waste generated by the electroplating industry, primarily from wastewater treatment during the electroplating process. Electroplating wastewater contains large amounts of heavy metal ions (such as copper, nickel, chromium, and zinc) and organic matter. After chemical precipitation and flocculation, these heavy metals and organic matter settle out as sludge. Electroplating sludge has a complex composition, containing high concentrations of heavy metals and organic matter, and is highly toxic and environmentally hazardous.

[0003] Currently, existing electroplating sludge treatment technologies have limitations. Simple physical treatment methods, such as gravity separation and magnetic separation, can only initially separate some metals from the sludge, making it difficult to recover high-purity metals and ineffective at removing organic pollutants. While some chemical treatment methods can achieve high metal extraction rates, they often suffer from complex processes, high costs, and the potential for secondary pollution. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for resource utilization of electroplating sludge to solve the problems raised in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solution: a method for resource utilization of electroplating sludge, comprising the following steps:

[0006] S1. Electroplating sludge pretreatment

[0007] Use mechanical dehydration methods, such as using plate and frame filter presses or centrifuges to separate water from electroplating sludge by mechanical pressure, or use thermal drying to accelerate water evaporation in a specific temperature environment, and strive to reduce the moisture content of electroplating sludge to below 50%;

[0008] Electroplating sludge that has completed dehydration is often compact and requires crushing equipment. A jaw crusher is used to crush the sludge to a particle size of approximately 5-10 mm. Subsequently, a vibrating screen is used to accurately remove large impurities such as plastic and stones, thereby obtaining sludge particles of uniform size, ensuring the smooth progress of subsequent treatment processes.

[0009] S2. Heavy metal extraction from sludge

[0010] The electroplating sludge that has completed the pretreatment process is fully mixed with a specific dilute acid, such as sulfuric acid solution or hydrochloric acid solution, in a pre-set ratio to start the acid leaching reaction process. During the acid leaching process, taking sulfuric acid as an example, the heavy metal ions contained in the electroplating sludge, such as copper ions, nickel ions, zinc ions, etc., will react chemically with sulfuric acid. The sulfuric acid ionizes hydrogen ions in the solution. The hydrogen ions have strong oxidizing properties and can destroy the lattice structure of heavy metal compounds, causing the heavy metal ions to dissolve from the solid sludge and enter the solution system;

[0011] After the acid leaching reaction is completed, the solid-liquid separation operation must be carried out in time to achieve effective separation of the leachate and the residue. The solid-liquid separation can be carried out by filtration or centrifugation. The filtration operation is completed with the help of a vacuum filtration device. The mixed liquid after the reaction is poured into a suction funnel covered with filter paper or filter cloth. The vacuum pump is turned on. Under the action of negative pressure, the leachate containing a large amount of heavy metal ions can smoothly pass through the pores of the filter paper or filter cloth and flow into the receiving container, while the solid residue is intercepted by the filter paper or filter cloth and remains in the funnel, thereby achieving preliminary separation of solid and liquid;

[0012] S3. Heavy metal recovery

[0013] After solid-liquid separation, a specific precipitant, such as sodium hydroxide or sodium sulfide, is precisely added to the leachate to induce a chemical reaction of heavy metal ions, converting them into insoluble precipitates. After the reaction is completed, separation is carried out by filtration or centrifugation. During filtration, the mixed solution is poured into a suction funnel covered with filter paper or filter cloth with the help of a vacuum filtration device. Under the action of negative pressure, the solid-liquid mixture containing heavy metal precipitates is separated from the solid and liquid, and the precipitate is retained on the filter paper. For centrifugation, a high-speed centrifuge is used. The mixed solution is placed in a centrifuge tube and centrifuged at a speed of 3000-5000 r / min for 10-20 minutes to allow the heavy metal precipitate to settle to the bottom of the centrifuge tube, thereby achieving efficient recovery of the heavy metal precipitate.

[0014] The leachate that has undergone preliminary treatment is introduced into the electrolytic cell for electrolytic recovery. The electrolytic cell is equipped with an anode and a cathode. When a DC power supply is connected, the heavy metal ions in the leachate move toward the cathode under the action of the electric field. Taking copper ions as an example, on the cathode surface, the copper ions obtain electrons, undergo a reduction reaction, and are reduced to metallic copper and deposited on the cathode. The reaction equation is Cu 2+ +2e - =Cu, in order to ensure the efficient and stable electrolysis process, it is necessary to accurately control the current density, electrolysis time and temperature and other parameters. Under normal circumstances, the current density is controlled at 100-300A / m 2 The electrolysis time is determined by the concentration of heavy metal ions in the leachate and the target recovery amount, usually 2-6 hours, and the temperature is maintained at 40-60°C;

[0015] S4. Treatment of residue after acid leaching

[0016] After the acid leaching process is completed, the acid leaching residue may still contain a certain amount of heavy metals. In order to reduce the environmental risks of these heavy metals, the residue needs to be solidified and stabilized. Common solidifying agents, such as cement and lime, are selected and fully mixed with the acid leaching residue in a specific ratio. The mixing ratio of cement to residue is determined according to the properties of the residue and the heavy metal content, generally between 1:4-1:6 (mass ratio). Lime adjusts the pH value of the system, causing the heavy metal ions to form insoluble hydroxide precipitation in an alkaline environment, further enhancing the stability of the heavy metals.

[0017] The physical and chemical properties of the residue after solidification and stabilization treatment are significantly improved, and it has the potential to be used in the production of building materials. The solidified residue can be used as a raw material in the production of building materials such as bricks and concrete aggregates. In the production of bricks, the solidified residue is mixed with an appropriate amount of clay, shale and other raw materials in a certain proportion. Generally, the solidified residue accounts for 20%-40% (mass ratio). Through mixing, blanking, drying and sintering processes, bricks with certain strength and durability are made. Since the solidified residue contains components such as silicon and calcium, it can react with other raw materials during the sintering process to form a stable mineral phase, thereby improving the quality of the bricks. For the preparation of concrete aggregates, the solidified residue is crushed to a suitable particle size range, such as 5-20 mm, to replace part of natural sand and gravel as coarse aggregate or fine aggregate of concrete;

[0018] S5. Treatment of organic matter in sludge

[0019] Pyrolysis technology is used to efficiently treat organic matter in electroplating sludge. During the pyrolysis process, pretreated electroplating sludge is placed in an oxygen-free or low-oxygen pyrolysis furnace. By precisely controlling the heating rate and reaction temperature, the organic matter in the sludge undergoes thermal decomposition. Generally speaking, the pyrolysis temperature range is set between 400-800°C. Within this temperature range, the complex organic matter in the sludge is gradually cracked and converted into combustible gases and solid residues. The main components of combustible gases include methane and hydrogen. These gases have high calorific value and can be collected and used as clean energy for power generation or heating systems. By burning combustible gases, chemical energy is converted into heat or electricity, achieving energy recycling and effectively reducing dependence on traditional fossil energy. The remaining solid residue, rich in inorganic components such as silicon and calcium, can be used as raw materials in the production of building materials after further processing. For example, it can be mixed with cement, sand and gravel to make bricks, blocks and other building materials with certain strength and durability, achieving resource recycling and reducing waste emissions.

[0020] With the help of microbial metabolic activities, the organic matter in the electroplating sludge is biodegraded. Microbial flora with high degradation capabilities are screened and cultivated, and inoculated into the electroplating sludge system. Under suitable environmental conditions, the microorganisms use the organic matter in the sludge as a carbon source and energy source, and through a series of complex enzymatic reactions, the organic matter is gradually decomposed and transformed. Under aerobic conditions, the microorganisms completely oxidize the organic matter, and the final products are harmless carbon dioxide and water, thereby reducing the organic pollutant content in the sludge and achieving harmless treatment;

[0021] S6. Treatment of wastewater after acid leaching

[0022] After the acid leaching process is completed, the wastewater generated is usually acidic. If it is discharged directly, it will cause serious acid pollution to the surrounding environment. Therefore, the wastewater after acid leaching needs to be neutralized. Select a suitable alkaline neutralizer, such as sodium hydroxide, calcium hydroxide, etc., and slowly add it to the wastewater. During the addition process, use a stirring device to fully mix the wastewater and the neutralizer to accelerate the acid-base neutralization reaction. At the same time, use a pH online monitor to monitor the pH value of the wastewater in real time, and accurately control the amount of neutralizer added until the pH value of the wastewater is adjusted to the neutral range. Generally, the pH value is controlled between 6-9;

[0023] A certain amount of heavy metal ions may still remain in the wastewater after neutralization treatment. To ensure that the wastewater can meet discharge standards, a series of efficient methods are needed to further remove heavy metal ions:

[0024] (1) Chemical precipitation method: Add specific precipitants to the wastewater, such as sodium sulfide, sodium carbonate, etc. For example, when sodium sulfide reacts with heavy metal ions in the wastewater, such as copper ions and lead ions, it will generate insoluble sulfide precipitates, such as copper sulfide and lead sulfide. During the reaction, the reaction temperature must be controlled at 30-50 ° C, and stirring must be continued to ensure that the precipitant is in full contact with the heavy metal ions. The reaction time is generally 1-2 hours. After the reaction is completed, the heavy metal precipitate is removed from the wastewater by solid-liquid separation methods such as precipitation and filtration.

[0025] (2) Ion exchange method: The selective adsorption characteristics of ion exchange resin for heavy metal ions are used to achieve removal. The wastewater containing heavy metal ions is passed through an exchange column filled with ion exchange resin. For example, for nickel ions in wastewater, a strong acidic cation exchange resin can be used. Under appropriate flow rate and temperature conditions, nickel ions exchange with exchangeable ions on the resin, such as hydrogen ions, and nickel ions are adsorbed on the resin, thereby significantly reducing the nickel ion concentration in the wastewater. When the resin is saturated with adsorption, the resin can be regenerated by an eluent, such as hydrochloric acid solution, to restore the adsorption capacity of the resin. At the same time, the eluted heavy metal ions can be further recycled.

[0026] (3) Adsorption method: Adsorbents with high specific surface area and strong adsorption properties, such as activated carbon and zeolite, are used to remove heavy metal ions from wastewater. The adsorbent is added to the wastewater. Under stirring conditions, heavy metal ions are adsorbed on the surface of the adsorbent through physical adsorption, chemical adsorption, etc. During the adsorption process, parameters such as adsorption time, temperature and adsorbent dosage need to be controlled. Generally, the adsorption time is 1-3 hours and the temperature is 25-40°C. The appropriate adsorbent dosage is determined according to the concentration of heavy metal ions in the wastewater.

[0027] S7. Utilization of resource products

[0028] The metal compound precipitates obtained after separation and extraction, such as copper sulfide and nickel hydroxide, can be prepared into metal products through a series of smelting processes. Taking copper sulfide as an example, it is first roasted at high temperature to convert it into copper oxide, and then reduced with hydrogen or electrolyzed to obtain high-purity metallic copper, which can be used in electrical and mechanical manufacturing industries.

[0029] The solid residue after acid leaching contains a certain amount of silicon, calcium and other components, which can be used to prepare building materials after proper treatment. For example, the residue can be mixed with cement, sand and gravel in a certain proportion to make bricks, blocks and other building materials, thereby realizing the comprehensive utilization of resources and reducing dependence on natural raw materials.

[0030] Preferably, in the above step S1, when a crusher is used to crush the sludge, it can not only significantly reduce the amount of materials to be processed subsequently, but also effectively reduce transportation costs, creating favorable conditions for the smooth development of subsequent processing procedures.

[0031] Preferably, in the above step S2, the reaction is usually carried out under stirring conditions, and the sludge is fully contacted with the dilute acid by mechanical stirring to accelerate the reaction rate. The reaction temperature is generally controlled at 60-80°C. This temperature range can not only ensure the efficient progress of the reaction, but also avoid the volatilization of the acid due to excessively high temperature and other side reactions that may be caused. The reaction time lasts for 1-3 hours. During this period, the heavy metal ions in the sludge are gradually dissolved into the solution, achieving preliminary separation of heavy metals and other impurities.

[0032] Preferably, in the above step S2, if centrifugal separation is adopted, a high-speed centrifuge can be selected to transfer the mixed liquid into a centrifuge tube, and the centrifuge speed is set to 3000-5000r / min. Under the strong centrifugal force generated by high-speed rotation, the solid residue with higher density quickly settles to the bottom of the centrifuge tube, and the supernatant is the leachate containing heavy metal ions. After solid-liquid separation, the leachate is rich in various heavy metal ions and becomes the key raw material for subsequent metal extraction; and the residue is mainly composed of inorganic substances such as silicates, which can be further used for other resource utilization methods.

[0033] Preferably, in the above step S4, a mechanical stirring device is used during the mixing process of cement and lime to ensure that the curing agent and the residue are evenly mixed. The stirring time is generally controlled to be 1-2 hours. After sufficient mixing, the mixture is allowed to stand for a period of time to allow a curing reaction to occur, forming a solidified body with a certain strength and stability, thereby effectively reducing the leaching toxicity of heavy metals in the residue.

[0034] Preferably, in the above-mentioned step S5, during the microbial metabolism process, some metabolites rich in nutrients such as nitrogen, phosphorus, and potassium will be produced. These products are combined with incompletely degraded organic matter to form a biological fertilizer with a certain fertility. Applying this biological fertilizer to the soil can improve the soil structure, increase soil fertility, provide nutrients for the growth of crops, promote the sustainable development of agricultural production, and also realize the resource utilization of electroplating sludge and reduce the negative impact on the environment.

[0035] Preferably, in the above step S6, after the adsorption is completed, the adsorbent is separated from the wastewater by filtration or centrifugation to achieve effective removal of heavy metal ions, ensure that the wastewater meets the national emission standards, and reduce pollution to the ecological environment.

[0036] Preferably, in the above-mentioned step S7, for the electroplating sludge containing a certain amount of nutrients such as nitrogen, phosphorus, and potassium, after harmless treatment and component adjustment, an attempt can be made to prepare it into an organic-inorganic compound fertilizer. By adding appropriate amounts of organic materials and nutrients, the nitrogen, phosphorus, and potassium ratio of the fertilizer is adjusted to meet the needs of agricultural production, and it can be used for soil improvement and crop fertilization, thereby realizing the resource utilization of waste and promoting the sustainable development of agriculture.

[0037] Compared with the prior art, the present invention provides a method for resource utilization of electroplating sludge, which has the following beneficial effects:

[0038] 1. This electroplating sludge resource utilization method efficiently recovers heavy metals such as copper and nickel that are urgently needed in the electronics and new energy industries from electroplating sludge with complex components. Compared with traditional simple physical treatment methods, its extraction purity is greatly improved, and it can directly provide high-quality metal raw materials for related industries. This effectively alleviates dependence on primary mineral resources, reduces energy consumption and ecological damage during the mining process, replenishes market metal resources at a lower cost, and promotes sustainable development of the industry.

[0039] 2. The method for resource utilization of electroplating sludge can harmlessly treat organic pollutants in electroplating sludge, thus avoiding the threat to the ecological environment and human health caused by their arbitrary discharge. Through reasonable treatment, it can prevent the pollution of crops caused by excessive heavy metals in the soil and the damage to the living environment of aquatic organisms caused by water pollution from the source. Compared with traditional treatment methods, it reduces the generation of secondary pollution, avoids the new environmental burden caused by improper treatment of a large amount of waste residue in the traditional acid leaching-neutralization precipitation method, and improves the quality of the surrounding ecological environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive work.

[0041] Figure 1 It is a flow chart of the preparation method of the present invention. DETAILED DESCRIPTION

[0042] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0043] In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connect," "fixed," etc. should be understood broadly. For example, they may refer to fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0044] The present invention provides the following technical solutions:

[0045] Example 1

[0046] Combine Figure 1 The method for resource utilization of electroplating sludge comprises the following steps:

[0047] S1. Electroplating sludge pretreatment

[0048] Use mechanical dehydration methods, such as using plate and frame filter presses or centrifuges to separate water from electroplating sludge by mechanical pressure, or use thermal drying to accelerate water evaporation in a specific temperature environment, and strive to reduce the moisture content of electroplating sludge to below 50%;

[0049] Electroplating sludge that has completed dehydration is often compact and requires crushing equipment. A jaw crusher is used to crush the sludge to a particle size of approximately 5-10 mm. Subsequently, a vibrating screen is used to accurately remove large impurities such as plastic and stones, thereby obtaining sludge particles of uniform size, ensuring the smooth progress of subsequent treatment processes.

[0050] S2. Heavy metal extraction from sludge

[0051] The electroplating sludge that has completed the pretreatment process is fully mixed with a specific dilute acid, such as sulfuric acid solution or hydrochloric acid solution, in a pre-set ratio to start the acid leaching reaction process. During the acid leaching process, taking sulfuric acid as an example, the heavy metal ions contained in the electroplating sludge, such as copper ions, nickel ions, zinc ions, etc., will react chemically with sulfuric acid. The sulfuric acid ionizes hydrogen ions in the solution. The hydrogen ions have strong oxidizing properties and can destroy the lattice structure of heavy metal compounds, causing the heavy metal ions to dissolve from the solid sludge and enter the solution system;

[0052] After the acid leaching reaction is completed, the solid-liquid separation operation must be carried out in time to achieve effective separation of the leachate and the residue. The solid-liquid separation can be carried out by filtration or centrifugation. The filtration operation is completed with the help of a vacuum filtration device. The mixed liquid after the reaction is poured into a suction funnel covered with filter paper or filter cloth. The vacuum pump is turned on. Under the action of negative pressure, the leachate containing a large amount of heavy metal ions can smoothly pass through the pores of the filter paper or filter cloth and flow into the receiving container, while the solid residue is intercepted by the filter paper or filter cloth and remains in the funnel, thereby achieving preliminary separation of solid and liquid;

[0053] S3. Heavy metal recovery

[0054] After solid-liquid separation, a specific precipitant, such as sodium hydroxide or sodium sulfide, is precisely added to the leachate to induce a chemical reaction of heavy metal ions, converting them into insoluble precipitates. After the reaction is completed, separation is carried out by filtration or centrifugation. During filtration, the mixed solution is poured into a suction funnel covered with filter paper or filter cloth with the help of a vacuum filtration device. Under the action of negative pressure, the solid-liquid mixture containing heavy metal precipitates is separated from the solid and liquid, and the precipitate is retained on the filter paper. For centrifugation, a high-speed centrifuge is used. The mixed solution is placed in a centrifuge tube and centrifuged at a speed of 3000-5000 r / min for 10-20 minutes to allow the heavy metal precipitate to settle to the bottom of the centrifuge tube, thereby achieving efficient recovery of the heavy metal precipitate.

[0055] The leachate that has undergone preliminary treatment is introduced into the electrolytic cell for electrolytic recovery. The electrolytic cell is equipped with an anode and a cathode. When a DC power supply is connected, the heavy metal ions in the leachate move toward the cathode under the action of the electric field. Taking copper ions as an example, on the cathode surface, the copper ions obtain electrons, undergo a reduction reaction, and are reduced to metallic copper and deposited on the cathode. The reaction equation is Cu 2+ +2e - =Cu, in order to ensure the efficient and stable electrolysis process, it is necessary to accurately control the current density, electrolysis time and temperature and other parameters. Under normal circumstances, the current density is controlled at 100-300A / m 2 The electrolysis time is determined by the concentration of heavy metal ions in the leachate and the target recovery amount, usually 2-6 hours, and the temperature is maintained at 40-60°C;

[0056] S4. Treatment of residue after acid leaching

[0057] After the acid leaching process is completed, the acid leaching residue may still contain a certain amount of heavy metals. In order to reduce the environmental risks of these heavy metals, the residue needs to be solidified and stabilized. Common solidifying agents, such as cement and lime, are selected and fully mixed with the acid leaching residue in a specific ratio. The mixing ratio of cement to residue is determined according to the properties of the residue and the heavy metal content, generally between 1:4-1:6 (mass ratio). Lime adjusts the pH value of the system, causing the heavy metal ions to form insoluble hydroxide precipitation in an alkaline environment, further enhancing the stability of the heavy metals.

[0058] The physical and chemical properties of the residue after solidification and stabilization treatment are significantly improved, and it has the potential to be used in the production of building materials. The solidified residue can be used as a raw material in the production of building materials such as bricks and concrete aggregates. In the production of bricks, the solidified residue is mixed with an appropriate amount of clay, shale and other raw materials in a certain proportion. Generally, the solidified residue accounts for 20%-40% (mass ratio). Through mixing, blanking, drying and sintering processes, bricks with certain strength and durability are made. Since the solidified residue contains components such as silicon and calcium, it can react with other raw materials during the sintering process to form a stable mineral phase, thereby improving the quality of the bricks. For the preparation of concrete aggregates, the solidified residue is crushed to a suitable particle size range, such as 5-20 mm, to replace part of natural sand and gravel as coarse aggregate or fine aggregate of concrete;

[0059] S5. Treatment of organic matter in sludge

[0060] Pyrolysis technology is used to efficiently treat organic matter in electroplating sludge. During the pyrolysis process, pretreated electroplating sludge is placed in an oxygen-free or low-oxygen pyrolysis furnace. By precisely controlling the heating rate and reaction temperature, the organic matter in the sludge undergoes thermal decomposition. Generally speaking, the pyrolysis temperature range is set between 400-800°C. Within this temperature range, the complex organic matter in the sludge is gradually cracked and converted into combustible gases and solid residues. The main components of combustible gases include methane and hydrogen. These gases have high calorific value and can be collected and used as clean energy for power generation or heating systems. By burning combustible gases, chemical energy is converted into heat or electricity, achieving energy recycling and effectively reducing dependence on traditional fossil energy. The remaining solid residue, rich in inorganic components such as silicon and calcium, can be used as raw materials in the production of building materials after further processing. For example, it can be mixed with cement, sand and gravel to make bricks, blocks and other building materials with certain strength and durability, achieving resource recycling and reducing waste emissions.

[0061] With the help of microbial metabolic activities, the organic matter in the electroplating sludge is biodegraded. Microbial flora with high degradation capabilities are screened and cultivated, and inoculated into the electroplating sludge system. Under suitable environmental conditions, the microorganisms use the organic matter in the sludge as a carbon source and energy source, and through a series of complex enzymatic reactions, the organic matter is gradually decomposed and transformed. Under aerobic conditions, the microorganisms completely oxidize the organic matter, and the final products are harmless carbon dioxide and water, thereby reducing the organic pollutant content in the sludge and achieving harmless treatment;

[0062] S6. Treatment of wastewater after acid leaching

[0063] After the acid leaching process is completed, the wastewater generated is usually acidic. If it is discharged directly, it will cause serious acid pollution to the surrounding environment. Therefore, the wastewater after acid leaching needs to be neutralized. Select a suitable alkaline neutralizer, such as sodium hydroxide, calcium hydroxide, etc., and slowly add it to the wastewater. During the addition process, use a stirring device to fully mix the wastewater and the neutralizer to accelerate the acid-base neutralization reaction. At the same time, use a pH online monitor to monitor the pH value of the wastewater in real time, and accurately control the amount of neutralizer added until the pH value of the wastewater is adjusted to the neutral range. Generally, the pH value is controlled between 6-9;

[0064] A certain amount of heavy metal ions may still remain in the wastewater after neutralization treatment. To ensure that the wastewater can meet discharge standards, a series of efficient methods are needed to further remove heavy metal ions:

[0065] (1) Chemical precipitation method: Add specific precipitants to the wastewater, such as sodium sulfide, sodium carbonate, etc. For example, when sodium sulfide reacts with heavy metal ions in the wastewater, such as copper ions and lead ions, it will generate insoluble sulfide precipitates, such as copper sulfide and lead sulfide. During the reaction, the reaction temperature must be controlled at 30-50 ° C, and stirring must be continued to ensure that the precipitant is in full contact with the heavy metal ions. The reaction time is generally 1-2 hours. After the reaction is completed, the heavy metal precipitate is removed from the wastewater by solid-liquid separation methods such as precipitation and filtration.

[0066] (2) Ion exchange method: The selective adsorption characteristics of ion exchange resin for heavy metal ions are used to achieve removal. The wastewater containing heavy metal ions is passed through an exchange column filled with ion exchange resin. For example, for nickel ions in wastewater, a strong acidic cation exchange resin can be used. Under appropriate flow rate and temperature conditions, nickel ions exchange with exchangeable ions on the resin, such as hydrogen ions, and nickel ions are adsorbed on the resin, thereby significantly reducing the nickel ion concentration in the wastewater. When the resin is saturated with adsorption, the resin can be regenerated by an eluent, such as hydrochloric acid solution, to restore the adsorption capacity of the resin. At the same time, the eluted heavy metal ions can be further recycled.

[0067] (3) Adsorption method: Adsorbents with high specific surface area and strong adsorption properties, such as activated carbon and zeolite, are used to remove heavy metal ions from wastewater. The adsorbent is added to the wastewater. Under stirring conditions, heavy metal ions are adsorbed on the surface of the adsorbent through physical adsorption, chemical adsorption, etc. During the adsorption process, parameters such as adsorption time, temperature and adsorbent dosage need to be controlled. Generally, the adsorption time is 1-3 hours and the temperature is 25-40°C. The appropriate adsorbent dosage is determined according to the concentration of heavy metal ions in the wastewater.

[0068] S7. Utilization of resource products

[0069] The metal compound precipitates obtained after separation and extraction, such as copper sulfide and nickel hydroxide, can be prepared into metal products through a series of smelting processes. Taking copper sulfide as an example, it is first roasted at high temperature to convert it into copper oxide, and then reduced with hydrogen or electrolyzed to obtain high-purity metallic copper, which can be used in electrical and mechanical manufacturing industries.

[0070] The solid residue after acid leaching contains a certain amount of silicon, calcium and other components, which can be used to prepare building materials after proper treatment. For example, the residue can be mixed with cement, sand and gravel in a certain proportion to make bricks, blocks and other building materials, thereby realizing the comprehensive utilization of resources and reducing dependence on natural raw materials.

[0071] Example 2

[0072] See Figure 1, and on the basis of Example 1, a method for resource utilization of electroplating sludge is further obtained, comprising the following steps:

[0073] S1. Electroplating sludge pretreatment

[0074] Use mechanical dehydration methods, such as using plate and frame filter presses or centrifuges to separate water from electroplating sludge by mechanical pressure, or use thermal drying to accelerate water evaporation in a specific temperature environment, and strive to reduce the moisture content of electroplating sludge to below 50%;

[0075] Electroplating sludge that has completed dehydration is often compact and requires crushing equipment. A jaw crusher is used to crush the sludge to a particle size of approximately 5-10 mm. Subsequently, a vibrating screen is used to accurately remove large impurities such as plastic and stones, thereby obtaining sludge particles of uniform size, ensuring the smooth progress of subsequent treatment processes.

[0076] S2. Heavy metal extraction from sludge

[0077] The electroplating sludge that has completed the pretreatment process is fully mixed with a specific dilute acid, such as sulfuric acid solution or hydrochloric acid solution, in a pre-set ratio to start the acid leaching reaction process. During the acid leaching process, taking sulfuric acid as an example, the heavy metal ions contained in the electroplating sludge, such as copper ions, nickel ions, zinc ions, etc., will react chemically with sulfuric acid. The sulfuric acid ionizes hydrogen ions in the solution. The hydrogen ions have strong oxidizing properties and can destroy the lattice structure of heavy metal compounds, causing the heavy metal ions to dissolve from the solid sludge and enter the solution system;

[0078] After the acid leaching reaction is completed, the solid-liquid separation operation must be carried out in time to achieve effective separation of the leachate and the residue. The solid-liquid separation can be carried out by filtration or centrifugation. The filtration operation is completed with the help of a vacuum filtration device. The mixed liquid after the reaction is poured into a suction funnel covered with filter paper or filter cloth. The vacuum pump is turned on. Under the action of negative pressure, the leachate containing a large amount of heavy metal ions can smoothly pass through the pores of the filter paper or filter cloth and flow into the receiving container, while the solid residue is intercepted by the filter paper or filter cloth and remains in the funnel, thereby achieving preliminary separation of solid and liquid;

[0079] S3. Heavy metal recovery

[0080] After solid-liquid separation, a specific precipitant, such as sodium hydroxide or sodium sulfide, is precisely added to the leachate to induce a chemical reaction of heavy metal ions, converting them into insoluble precipitates. After the reaction is completed, separation is carried out by filtration or centrifugation. During filtration, the mixed solution is poured into a suction funnel covered with filter paper or filter cloth with the help of a vacuum filtration device. Under the action of negative pressure, the solid-liquid mixture containing heavy metal precipitates is separated from the solid and liquid, and the precipitate is retained on the filter paper. For centrifugation, a high-speed centrifuge is used. The mixed solution is placed in a centrifuge tube and centrifuged at a speed of 3000-5000 r / min for 10-20 minutes to allow the heavy metal precipitate to settle to the bottom of the centrifuge tube, thereby achieving efficient recovery of the heavy metal precipitate.

[0081] The leachate that has undergone preliminary treatment is introduced into the electrolytic cell for electrolytic recovery. The electrolytic cell is equipped with an anode and a cathode. When a DC power supply is connected, the heavy metal ions in the leachate move toward the cathode under the action of the electric field. Taking copper ions as an example, on the cathode surface, the copper ions obtain electrons, undergo a reduction reaction, and are reduced to metallic copper and deposited on the cathode. The reaction equation is Cu 2+ +2e - =Cu, in order to ensure the efficient and stable electrolysis process, it is necessary to accurately control the current density, electrolysis time and temperature and other parameters. Under normal circumstances, the current density is controlled at 100-300A / m 2 The electrolysis time is determined by the concentration of heavy metal ions in the leachate and the target recovery amount, usually 2-6 hours, and the temperature is maintained at 40-60°C;

[0082] S4. Treatment of residue after acid leaching

[0083] After the acid leaching process is completed, the acid leaching residue may still contain a certain amount of heavy metals. In order to reduce the environmental risks of these heavy metals, the residue needs to be solidified and stabilized. Common solidifying agents, such as cement and lime, are selected and fully mixed with the acid leaching residue in a specific ratio. The mixing ratio of cement to residue is determined according to the properties of the residue and the heavy metal content, generally between 1:4-1:6 (mass ratio). Lime adjusts the pH value of the system, causing the heavy metal ions to form insoluble hydroxide precipitation in an alkaline environment, further enhancing the stability of the heavy metals.

[0084] The physical and chemical properties of the residue after solidification and stabilization treatment are significantly improved, and it has the potential to be used in the production of building materials. The solidified residue can be used as a raw material in the production of building materials such as bricks and concrete aggregates. In the production of bricks, the solidified residue is mixed with an appropriate amount of clay, shale and other raw materials in a certain proportion. Generally, the solidified residue accounts for 20%-40% (mass ratio). Through mixing, blanking, drying and sintering processes, bricks with certain strength and durability are made. Since the solidified residue contains components such as silicon and calcium, it can react with other raw materials during the sintering process to form a stable mineral phase, thereby improving the quality of the bricks. For the preparation of concrete aggregates, the solidified residue is crushed to a suitable particle size range, such as 5-20 mm, to replace part of natural sand and gravel as coarse aggregate or fine aggregate of concrete;

[0085] S5. Treatment of organic matter in sludge

[0086] Pyrolysis technology is used to efficiently treat organic matter in electroplating sludge. During the pyrolysis process, pretreated electroplating sludge is placed in an oxygen-free or low-oxygen pyrolysis furnace. By precisely controlling the heating rate and reaction temperature, the organic matter in the sludge undergoes thermal decomposition. Generally speaking, the pyrolysis temperature range is set between 400-800°C. Within this temperature range, the complex organic matter in the sludge is gradually cracked and converted into combustible gases and solid residues. The main components of combustible gases include methane and hydrogen. These gases have high calorific value and can be collected and used as clean energy for power generation or heating systems. By burning combustible gases, chemical energy is converted into heat or electricity, achieving energy recycling and effectively reducing dependence on traditional fossil energy. The remaining solid residue, rich in inorganic components such as silicon and calcium, can be used as raw materials in the production of building materials after further processing. For example, it can be mixed with cement, sand and gravel to make bricks, blocks and other building materials with certain strength and durability, achieving resource recycling and reducing waste emissions.

[0087] With the help of microbial metabolic activities, the organic matter in the electroplating sludge is biodegraded. Microbial flora with high degradation capabilities are screened and cultivated, and inoculated into the electroplating sludge system. Under suitable environmental conditions, the microorganisms use the organic matter in the sludge as a carbon source and energy source, and through a series of complex enzymatic reactions, the organic matter is gradually decomposed and transformed. Under aerobic conditions, the microorganisms completely oxidize the organic matter, and the final products are harmless carbon dioxide and water, thereby reducing the organic pollutant content in the sludge and achieving harmless treatment;

[0088] S6. Treatment of wastewater after acid leaching

[0089] After the acid leaching process is completed, the wastewater generated is usually acidic. If it is discharged directly, it will cause serious acid pollution to the surrounding environment. Therefore, the wastewater after acid leaching needs to be neutralized. Select a suitable alkaline neutralizer, such as sodium hydroxide, calcium hydroxide, etc., and slowly add it to the wastewater. During the addition process, use a stirring device to fully mix the wastewater and the neutralizer to accelerate the acid-base neutralization reaction. At the same time, use a pH online monitor to monitor the pH value of the wastewater in real time, and accurately control the amount of neutralizer added until the pH value of the wastewater is adjusted to the neutral range. Generally, the pH value is controlled between 6-9;

[0090] A certain amount of heavy metal ions may still remain in the wastewater after neutralization treatment. To ensure that the wastewater can meet discharge standards, a series of efficient methods are needed to further remove heavy metal ions:

[0091] (1) Chemical precipitation method: Add specific precipitants to the wastewater, such as sodium sulfide, sodium carbonate, etc. For example, when sodium sulfide reacts with heavy metal ions in the wastewater, such as copper ions and lead ions, it will generate insoluble sulfide precipitates, such as copper sulfide and lead sulfide. During the reaction, the reaction temperature must be controlled at 30-50 ° C, and stirring must be continued to ensure that the precipitant is in full contact with the heavy metal ions. The reaction time is generally 1-2 hours. After the reaction is completed, the heavy metal precipitate is removed from the wastewater by solid-liquid separation methods such as precipitation and filtration.

[0092] (2) Ion exchange method: The selective adsorption characteristics of ion exchange resin for heavy metal ions are used to achieve removal. The wastewater containing heavy metal ions is passed through an exchange column filled with ion exchange resin. For example, for nickel ions in wastewater, a strong acidic cation exchange resin can be used. Under appropriate flow rate and temperature conditions, nickel ions exchange with exchangeable ions on the resin, such as hydrogen ions, and nickel ions are adsorbed on the resin, thereby significantly reducing the nickel ion concentration in the wastewater. When the resin is saturated with adsorption, the resin can be regenerated by an eluent, such as hydrochloric acid solution, to restore the adsorption capacity of the resin. At the same time, the eluted heavy metal ions can be further recycled.

[0093] (3) Adsorption method: Adsorbents with high specific surface area and strong adsorption properties, such as activated carbon and zeolite, are used to remove heavy metal ions from wastewater. The adsorbent is added to the wastewater. Under stirring conditions, heavy metal ions are adsorbed on the surface of the adsorbent through physical adsorption, chemical adsorption, etc. During the adsorption process, parameters such as adsorption time, temperature and adsorbent dosage need to be controlled. Generally, the adsorption time is 1-3 hours and the temperature is 25-40°C. The appropriate adsorbent dosage is determined according to the concentration of heavy metal ions in the wastewater.

[0094] S7. Utilization of resource products

[0095] The metal compound precipitates obtained after separation and extraction, such as copper sulfide and nickel hydroxide, can be prepared into metal products through a series of smelting processes. Taking copper sulfide as an example, it is first roasted at high temperature to convert it into copper oxide, and then reduced with hydrogen or electrolyzed to obtain high-purity metallic copper, which can be used in electrical and mechanical manufacturing industries.

[0096] The solid residue after acid leaching contains a certain amount of silicon, calcium and other components, which can be used to prepare building materials after proper treatment. For example, the residue can be mixed with cement, sand and gravel in a certain proportion to make bricks, blocks and other building materials, thereby realizing the comprehensive utilization of resources and reducing dependence on natural raw materials.

[0097] In the above step S1, when a crusher is used to crush the sludge, it can not only significantly reduce the amount of materials to be processed subsequently, but also effectively reduce transportation costs, creating favorable conditions for the smooth implementation of subsequent processing steps;

[0098] In step S2, the reaction is usually carried out under stirring conditions. Mechanical stirring is used to ensure that the sludge is fully in contact with the dilute acid to accelerate the reaction rate. The reaction temperature is generally controlled at 60-80°C. This temperature range can ensure efficient reaction while avoiding acid volatilization and other side reactions caused by excessively high temperature. The reaction time lasts for 1-3 hours. During this period, the heavy metal ions in the sludge are gradually dissolved into the solution, achieving preliminary separation of the heavy metals from other impurities.

[0099] In the above step S2, if centrifugal separation is adopted, a high-speed centrifuge can be selected to transfer the mixed liquid into a centrifuge tube, and the centrifuge speed is set to 3000-5000 r / min. Under the strong centrifugal force generated by the high-speed rotation, the solid residue with a higher density quickly settles to the bottom of the centrifuge tube, and the supernatant is the leachate containing heavy metal ions. After solid-liquid separation, the leachate is rich in various heavy metal ions and becomes the key raw material for subsequent metal extraction; the residue is mainly composed of inorganic substances such as silicates, which can be further used for other resource utilization methods;

[0100] In the above step S4, during the mixing process of cement and lime, a mechanical stirring device is used to ensure that the curing agent and the residue are evenly mixed. The stirring time is generally controlled to be 1-2 hours. After sufficient mixing, the mixture is allowed to stand for a period of time to allow a curing reaction to occur, forming a solidified body with a certain strength and stability, thereby effectively reducing the leaching toxicity of heavy metals in the residue;

[0101] In step S5, during the microbial metabolism process, metabolites rich in nutrients such as nitrogen, phosphorus, and potassium are produced. These products, combined with incompletely degraded organic matter, can form a biofertilizer with a certain fertility. Applying this biofertilizer to the soil can improve soil structure, increase soil fertility, provide nutrients for crop growth, promote the sustainable development of agricultural production, and also realize the resource utilization of electroplating sludge, reducing the negative impact on the environment.

[0102] In the above step S6, after the adsorption is completed, the adsorbent is separated from the wastewater by filtration or centrifugation to achieve effective removal of heavy metal ions, ensure that the wastewater meets the national emission standards, and reduce pollution to the ecological environment;

[0103] In the above step S7, for electroplating sludge containing a certain amount of nutrients such as nitrogen, phosphorus, and potassium, after harmless treatment and component adjustment, an attempt can be made to prepare it into an organic-inorganic compound fertilizer. By adding appropriate amounts of organic materials and nutrients, the nitrogen, phosphorus, and potassium ratio of the fertilizer is adjusted to meet the needs of agricultural production, and it can be used for soil improvement and crop fertilization, thereby realizing the resource utilization of waste and promoting the sustainable development of agriculture.

[0104] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a..." does not exclude the presence of additional identical elements in the process, method, article, or device comprising the element.

Claims

1. A method for resource utilization of electroplating sludge, comprising the following steps: S1. Electroplating sludge pretreatment Use mechanical dehydration methods, such as using plate and frame filter presses or centrifuges to separate water from electroplating sludge by mechanical pressure, or use thermal drying to accelerate water evaporation in a specific temperature environment, and strive to reduce the moisture content of electroplating sludge to below 50%; Electroplating sludge that has completed dehydration is often compact and requires crushing equipment. A jaw crusher is used to crush the sludge to a particle size of approximately 5-10 mm. Subsequently, a vibrating screen is used to accurately remove large impurities such as plastic and stones, thereby obtaining sludge particles of uniform size, ensuring the smooth progress of subsequent treatment processes. S2. Heavy metal extraction from sludge The electroplating sludge that has completed the pretreatment process is fully mixed with a specific dilute acid, such as sulfuric acid solution or hydrochloric acid solution, in a pre-set ratio to start the acid leaching reaction process. During the acid leaching process, taking sulfuric acid as an example, the heavy metal ions contained in the electroplating sludge, such as copper ions, nickel ions, zinc ions, etc., will react chemically with sulfuric acid. The sulfuric acid ionizes hydrogen ions in the solution. The hydrogen ions have strong oxidizing properties and can destroy the lattice structure of heavy metal compounds, causing the heavy metal ions to dissolve from the solid sludge and enter the solution system; After the acid leaching reaction is completed, the solid-liquid separation operation must be carried out in time to achieve effective separation of the leachate and the residue. The solid-liquid separation can be carried out by filtration or centrifugation. The filtration operation is completed with the help of a vacuum filtration device. The mixed liquid after the reaction is poured into a suction funnel covered with filter paper or filter cloth. The vacuum pump is turned on. Under the action of negative pressure, the leachate containing a large amount of heavy metal ions can smoothly pass through the pores of the filter paper or filter cloth and flow into the receiving container, while the solid residue is intercepted by the filter paper or filter cloth and remains in the funnel, thereby achieving preliminary separation of solid and liquid; S3. Heavy metal recovery After solid-liquid separation, a specific precipitant, such as sodium hydroxide or sodium sulfide, is precisely added to the leachate to induce a chemical reaction of heavy metal ions, converting them into insoluble precipitates. After the reaction is completed, separation is carried out by filtration or centrifugation. During filtration, the mixed solution is poured into a suction funnel covered with filter paper or filter cloth with the help of a vacuum filtration device. Under the action of negative pressure, the solid-liquid mixture containing heavy metal precipitates is separated from the solid and liquid, and the precipitate is retained on the filter paper. For centrifugation, a high-speed centrifuge is used. The mixed solution is placed in a centrifuge tube and centrifuged at a speed of 3000-5000 r / min for 10-20 minutes to allow the heavy metal precipitate to settle to the bottom of the centrifuge tube, thereby achieving efficient recovery of the heavy metal precipitate. The leachate that has undergone preliminary treatment is introduced into the electrolytic cell for electrolytic recovery. The electrolytic cell is equipped with an anode and a cathode. When a DC power supply is connected, the heavy metal ions in the leachate move toward the cathode under the action of the electric field. Taking copper ions as an example, on the cathode surface, the copper ions obtain electrons, undergo a reduction reaction, and are reduced to metallic copper and deposited on the cathode. The reaction equation is Cu 2+ +2e - =Cu, in order to ensure the efficient and stable electrolysis process, it is necessary to accurately control the current density, electrolysis time and temperature and other parameters. Under normal circumstances, the current density is controlled at 100-300A / m 2 The electrolysis time is determined by the concentration of heavy metal ions in the leachate and the target recovery amount, usually 2-6 hours, and the temperature is maintained at 40-60°C; S4. Treatment of residue after acid leaching After the acid leaching process is completed, the acid leaching residue may still contain a certain amount of heavy metals. In order to reduce the environmental risks of these heavy metals, the residue needs to be solidified and stabilized. Common solidifying agents, such as cement and lime, are selected and fully mixed with the acid leaching residue in a specific ratio. The mixing ratio of cement to residue is determined according to the properties of the residue and the heavy metal content, generally between 1:4-1:6 (mass ratio). Lime adjusts the pH value of the system, causing the heavy metal ions to form insoluble hydroxide precipitation in an alkaline environment, further enhancing the stability of the heavy metals. The physical and chemical properties of the residue after solidification and stabilization treatment are significantly improved, and it has the potential to be used in the production of building materials. The solidified residue can be used as a raw material in the production of building materials such as bricks and concrete aggregates. In the production of bricks, the solidified residue is mixed with an appropriate amount of clay, shale and other raw materials in a certain proportion. Generally, the solidified residue accounts for 20%-40% (mass ratio). Through mixing, blanking, drying and sintering processes, bricks with certain strength and durability are made. Since the solidified residue contains components such as silicon and calcium, it can react with other raw materials during the sintering process to form a stable mineral phase, thereby improving the quality of the bricks. For the preparation of concrete aggregates, the solidified residue is crushed to a suitable particle size range, such as 5-20 mm, to replace part of natural sand and gravel as coarse aggregate or fine aggregate of concrete; S5. Treatment of organic matter in sludge Pyrolysis technology is used to efficiently treat organic matter in electroplating sludge. During the pyrolysis process, pretreated electroplating sludge is placed in an oxygen-free or low-oxygen pyrolysis furnace. By precisely controlling the heating rate and reaction temperature, the organic matter in the sludge undergoes thermal decomposition. Generally speaking, the pyrolysis temperature range is set between 400-800°C. Within this temperature range, the complex organic matter in the sludge is gradually cracked and converted into combustible gases and solid residues. The main components of combustible gases include methane and hydrogen. These gases have high calorific value and can be collected and used as clean energy for power generation or heating systems. By burning combustible gases, chemical energy is converted into heat or electricity, achieving energy recycling and effectively reducing dependence on traditional fossil energy. The remaining solid residue, rich in inorganic components such as silicon and calcium, can be used as raw materials in the production of building materials after further processing. For example, it can be mixed with cement, sand and gravel to make bricks, blocks and other building materials with certain strength and durability, achieving resource recycling and reducing waste emissions. With the help of microbial metabolic activities, the organic matter in the electroplating sludge is biodegraded. Microbial flora with high degradation capabilities are screened and cultivated, and inoculated into the electroplating sludge system. Under suitable environmental conditions, the microorganisms use the organic matter in the sludge as a carbon source and energy source, and through a series of complex enzymatic reactions, the organic matter is gradually decomposed and transformed. Under aerobic conditions, the microorganisms completely oxidize the organic matter, and the final products are harmless carbon dioxide and water, thereby reducing the organic pollutant content in the sludge and achieving harmless treatment; S6. Treatment of wastewater after acid leaching After the acid leaching process is completed, the wastewater generated is usually acidic. If it is discharged directly, it will cause serious acid pollution to the surrounding environment. Therefore, the wastewater after acid leaching needs to be neutralized. Select a suitable alkaline neutralizer, such as sodium hydroxide, calcium hydroxide, etc., and slowly add it to the wastewater. During the addition process, use a stirring device to fully mix the wastewater and the neutralizer to accelerate the acid-base neutralization reaction. At the same time, use a pH online monitor to monitor the pH value of the wastewater in real time, and accurately control the amount of neutralizer added until the pH value of the wastewater is adjusted to the neutral range. Generally, the pH value is controlled between 6-9; A certain amount of heavy metal ions may still remain in the wastewater after neutralization treatment. To ensure that the wastewater can meet discharge standards, a series of efficient methods are needed to further remove heavy metal ions: (1) Chemical precipitation method: Add specific precipitants to the wastewater, such as sodium sulfide, sodium carbonate, etc. For example, when sodium sulfide reacts with heavy metal ions in the wastewater, such as copper ions and lead ions, it will generate insoluble sulfide precipitates, such as copper sulfide and lead sulfide. During the reaction, the reaction temperature must be controlled at 30-50 ° C, and stirring must be continued to ensure that the precipitant is in full contact with the heavy metal ions. The reaction time is generally 1-2 hours. After the reaction is completed, the heavy metal precipitate is removed from the wastewater by solid-liquid separation methods such as precipitation and filtration. (2) Ion exchange method: The selective adsorption characteristics of ion exchange resin for heavy metal ions are used to achieve removal. The wastewater containing heavy metal ions is passed through an exchange column filled with ion exchange resin. For example, for nickel ions in wastewater, a strong acidic cation exchange resin can be used. Under appropriate flow rate and temperature conditions, nickel ions exchange with exchangeable ions on the resin, such as hydrogen ions, and nickel ions are adsorbed on the resin, thereby significantly reducing the nickel ion concentration in the wastewater. When the resin is saturated with adsorption, the resin can be regenerated by an eluent, such as hydrochloric acid solution, to restore the adsorption capacity of the resin. At the same time, the eluted heavy metal ions can be further recycled. (3) Adsorption method: Adsorbents with high specific surface area and strong adsorption properties, such as activated carbon and zeolite, are used to remove heavy metal ions from wastewater. The adsorbent is added to the wastewater. Under stirring conditions, heavy metal ions are adsorbed on the surface of the adsorbent through physical adsorption, chemical adsorption, etc. During the adsorption process, parameters such as adsorption time, temperature and adsorbent dosage need to be controlled. Generally, the adsorption time is 1-3 hours and the temperature is 25-40°C. The appropriate adsorbent dosage is determined according to the concentration of heavy metal ions in the wastewater. S7. Utilization of resource products The metal compound precipitates obtained after separation and extraction, such as copper sulfide and nickel hydroxide, can be prepared into metal products through a series of smelting processes. Taking copper sulfide as an example, it is first roasted at high temperature to convert it into copper oxide, and then reduced with hydrogen or electrolyzed to obtain high-purity metallic copper, which can be used in electrical and mechanical manufacturing industries. The solid residue after acid leaching contains a certain amount of silicon, calcium and other components, which can be used to prepare building materials after proper treatment. For example, the residue can be mixed with cement, sand and gravel in a certain proportion to make bricks, blocks and other building materials, thereby realizing the comprehensive utilization of resources and reducing dependence on natural raw materials.

2. The method for resource utilization of electroplating sludge according to claim 1, characterized in that: In the above step S1, when a crusher is used to crush the sludge, it can not only significantly reduce the amount of materials to be processed subsequently, but also effectively reduce transportation costs, creating favorable conditions for the smooth implementation of subsequent processing procedures.

3. The method for resource utilization of electroplating sludge according to claim 1, characterized in that: In the above-mentioned step S2, the reaction is usually carried out under stirring conditions. The sludge is fully contacted with the dilute acid through mechanical stirring to accelerate the reaction rate. The reaction temperature is generally controlled at 60-80°C. This temperature range can not only ensure the efficient progress of the reaction, but also avoid the volatilization of the acid due to excessively high temperature and other side reactions that may be caused. The reaction time lasts for 1-3 hours. During this period, the heavy metal ions in the sludge are gradually dissolved into the solution, achieving preliminary separation of heavy metals and other impurities.

4. The method for resource utilization of electroplating sludge according to claim 1, characterized in that: In the above step S2, if centrifugal separation is adopted, a high-speed centrifuge can be selected to transfer the mixed liquid into a centrifuge tube, and the centrifuge speed is set to 3000-5000r / min. Under the strong centrifugal force generated by high-speed rotation, the solid residue with higher density quickly settles to the bottom of the centrifuge tube, and the supernatant is the leachate containing heavy metal ions. After solid-liquid separation, the leachate is rich in various heavy metal ions and becomes the key raw material for subsequent metal extraction; the residue is mainly composed of inorganic substances such as silicates, which can be further used for other resource utilization methods.

5. The method for resource utilization of electroplating sludge according to claim 1, characterized in that: In the above-mentioned step S4, during the mixing process of cement and lime, a mechanical stirring device is used to ensure that the curing agent and the residue are evenly mixed. The stirring time is generally controlled to be 1-2 hours. After sufficient mixing, the mixture is allowed to stand for a period of time to allow a curing reaction to occur, forming a solidified body with a certain strength and stability, thereby effectively reducing the leaching toxicity of heavy metals in the residue.

6. The method for resource utilization of electroplating sludge according to claim 5, characterized in that: In the above-mentioned step S5, during the microbial metabolism process, some metabolites rich in nutrients such as nitrogen, phosphorus, and potassium will be produced. These products, combined with incompletely degraded organic matter, can form a biofertilizer with a certain fertility. Applying this biofertilizer to the soil can improve the soil structure, increase soil fertility, provide nutrients for the growth of crops, and promote the sustainable development of agricultural production. At the same time, it also realizes the resource utilization of electroplating sludge and reduces the negative impact on the environment.

7. The method for resource utilization of electroplating sludge according to claim 5, characterized in that: In the above step S6, after the adsorption is completed, the adsorbent is separated from the wastewater by filtration or centrifugation to achieve effective removal of heavy metal ions, ensure that the wastewater meets the national emission standards, and reduce pollution to the ecological environment.

8. The method for resource utilization of electroplating sludge according to claim 5, characterized in that: In the above-mentioned step S7, for the electroplating sludge containing a certain amount of nutrients such as nitrogen, phosphorus, and potassium, after harmless treatment and component adjustment, an attempt can be made to prepare it into an organic-inorganic compound fertilizer. By adding appropriate amounts of organic materials and nutrients, the nitrogen, phosphorus, and potassium ratio of the fertilizer is adjusted to meet the needs of agricultural production, and it can be used for soil improvement and crop fertilization, thereby realizing the resource utilization of waste and promoting the sustainable development of agriculture.

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