Metal lead-zinc-tin recovery system and recovery method thereof

Abstract

The invention discloses a metal lead-zinc-tin recovery system and a recovery method thereof, and relates to the technical field of metal recovery. The system comprises a feed pretreatment unit, a chemical stripping reactor connected with the feed pretreatment unit, a solid-liquid separation device connected with the chemical stripping reactor, an impurity purification reduction tank connected with a filtrate outlet of the solid-liquid separation device, and an electrolytic recovery tank connected with the impurity purification reduction tank, the residue treatment unit is connected with a solid outlet of the solid-liquid separation device, and the solution circulation pipeline is connected with an electrolyte outlet of the electrolytic recovery tank and an alkali liquor supply port of the chemical stripping reactor. According to the method, the graded recovery process of alkaline leaching, purification, electrolysis and smelting is adopted, tin is selectively dissolved out in a sodium stannate form preferentially, lead and zinc are reserved in a solid phase, primary efficient separation of tin and lead and zinc is achieved, then impurity purification and reduction treatment is conducted on a tin-containing liquid phase, and the purity of the electrolyte is remarkably improved.

Description

Technical Field

[0001] This invention belongs to the field of metal recycling technology, and in particular relates to a metal lead, zinc and tin recycling system and recycling method. Background Technology

[0002] Currently, the recycling technologies for lead-zinc-tin mixtures are mainly divided into three categories: pyrometallurgy, hydrometallurgy, and combined pyrometallurgical and hydrometallurgical processes.

[0003] Pyrometallurgical technologies, such as blast furnace smelting, electric furnace smelting, or vacuum distillation, have the advantages of large processing capacity and short process flow, but they generally suffer from high energy consumption, complex flue gas treatment, and the easy generation of toxic substances such as dioxins. More importantly, due to the differences in boiling points and vapor pressures of lead, zinc, and tin, pyrometallurgical processes cannot achieve efficient and precise separation of the three, and usually only crude alloys with complex compositions can be obtained, which still require subsequent refining, thus limiting the overall recovery purity and efficiency.

[0004] Traditional wet leaching processes often employ acidic systems (such as sulfuric acid and hydrochloric acid) for leaching. However, acid leaching faces numerous challenges: First, lead readily forms insoluble lead sulfate (PbSO4) or basic salt precipitates under acidic conditions, which can coat other metal particles and affect leaching efficiency. Second, zinc and tin are both readily soluble in acidic media, making selective separation difficult and complicating subsequent separation and purification processes. Furthermore, acidic systems cause severe corrosion to equipment, and the resulting acidic wastewater and residue are difficult and costly to treat, posing significant environmental risks.

[0005] To overcome the drawbacks of acid leaching, some research has shifted towards alkaline leaching systems. Tin is known to dissolve in strong alkalis to form stannates (such as Na₂SnO₃), while lead and zinc have extremely low solubility under alkaline conditions. Lead forms PbO or Pb(OH)₂, and although zinc can form [Zn(OH)₄]₂⁻, its stability is poor and it is easily hydrolyzed and precipitated. This provides a theoretical basis for the selective extraction of tin. However, existing alkaline leaching processes generally suffer from low leaching efficiency, long reaction times, and high alkali consumption. Furthermore, they are incomplete in removing trace amounts of lead, zinc, and other impurities remaining in the leached liquid phase, directly affecting the purity of subsequent electrolytic tin. In addition, traditional processes often lack precise control over the reaction process and resource recycling, resulting in high operating costs and making stable industrial-scale operation difficult.

[0006] To address these issues, we provide a lead-zinc-tin metal recycling system and method. Summary of the Invention

[0007] To solve the above-mentioned technical problems, the present invention is achieved through the following technical solution:

[0008] This invention relates to a metal lead, zinc, and tin recycling system, comprising:

[0009] The feed pretreatment unit is used to crush, magnetically separate and screen mixed metal materials containing lead, zinc and tin to obtain pretreated materials with a particle size of less than 5mm.

[0010] A chemical stripping reactor, connected to the feed pretreatment unit, is used to contain a sodium hydroxide solution with a concentration of 80-120 g / L, and to add the pretreated material into it. The chemical stripping reaction is carried out at a temperature of 85-95℃ for 1.5-2.5 h, so that tin enters the liquid phase in the form of sodium stannate, while lead and zinc remain in the solid phase.

[0011] A solid-liquid separation device, connected to the chemical stripping reactor, is used to separate the mixture after the chemical stripping reaction to obtain a tin-containing filtrate and a lead-zinc-containing filter residue.

[0012] The impurity purification and reduction tank is connected to the filtrate outlet of the solid-liquid separation device. It is used to receive the tin-containing filtrate and introduce a mixed gas of hydrogen sulfide and nitrogen at a volume ratio of 1:4. The impurity purification and reduction reaction is carried out at 60-70℃ for 1-1.5 hours, so that lead and zinc impurity ions precipitate in the form of sulfides.

[0013] An electrolytic recovery cell, connected to the impurity purification and reduction cell, is used to receive the purified tin-containing solution. It uses a stainless steel plate as the cathode and an iridium-tantalum coated titanium plate as the anode, operating at a DC voltage of 2.8-3.6V and a current density of 180-240A / m. 2 Electrolysis is performed under certain conditions to deposit tin on the cathode surface;

[0014] The residue treatment unit is connected to the solid outlet of the solid-liquid separation device and is used to dry and smelt the lead-zinc filter residue at high temperature to obtain a lead-zinc alloy.

[0015] A solution circulation pipeline connects the electrolyte outlet of the electrolytic recovery tank to the alkali supply port of the chemical stripping reactor, and is used to return the electrolyzed solution to the chemical stripping reactor.

[0016] An online monitoring and regulation device is installed on the solution circulation pipeline to detect the pH value of the returned solution and regulate the replenishment flow rate.

[0017] The present invention is further configured such that the stirring in the chemical stripping reactor is achieved by an S-shaped curved surface stirring paddle, wherein the stirring paddle is arranged in three groups at equal intervals along the vertical axis, and each group contains four blades evenly distributed along the circumference.

[0018] The present invention is further configured such that an annular gas distributor is provided at the top of the impurity purification and reduction tank, and an inclined through hole is provided on the lower surface of the gas distributor for uniformly releasing reducing gas.

[0019] The present invention is further configured such that an insulating partition is provided between the cathode plate and the anode plate in the electrolytic recovery tank, and the height of the insulating partition is 10-15 cm lower than the electrolyte surface.

[0020] The present invention is further configured such that the feed pretreatment unit (100) includes a crusher, a magnetic separator and a double-layer vibrating screen, and the residue treatment unit includes a drying kiln and a melting furnace, wherein the heat source of the drying kiln comes from the waste heat recovery system of the chemical stripping reactor.

[0021] The present invention is further configured such that the impurity purification and reduction tank is provided with a fixed bed carrier filled with supported catalyst particles, and the electrolytic recovery tank is equipped with an automatic scraper device.

[0022] A recycling method for a lead-zinc-tin metal recycling system includes the following steps:

[0023] The mixed metal material containing lead, zinc and tin is subjected to crushing, magnetic separation and screening in sequence to obtain pretreated material with a particle size of less than 5 mm.

[0024] The pretreated material is added to a sodium hydroxide solution with a concentration of 80-120 g / L and stirred at 85-95°C for 1.5-2.5 h to perform chemical stripping and dissolve the tin.

[0025] The mixture after chemical stripping is subjected to solid-liquid separation to obtain tin-containing filtrate and lead-zinc-containing filter residue; a mixture of hydrogen sulfide and nitrogen gas with a volume ratio of 1:4 is introduced into the tin-containing filtrate and reacted at 60-70℃ for 1-1.5h to purify and reduce impurities, causing lead and zinc impurities to precipitate.

[0026] The purified tin-containing solution was subjected to liquid-solid separation to obtain a purified solution; the purified solution was then subjected to a DC voltage of 2.8-3.6V and a current density of 180-240A / m. 2 Electrolysis is performed under specific conditions, during which tin is reduced and deposited on the cathode surface. The electrolyzed solution is then returned to the chemical stripping process as alkali replenishment, during which the pH value of the solution is monitored and the flow rate is adjusted.

[0027] The deposited metallic tin on the cathode surface is scraped off and collected; the lead-zinc filter residue is dried and smelted at high temperature to obtain a lead-zinc alloy.

[0028] The present invention is further configured such that, in the chemical stripping reaction, the liquid-solid mass ratio of sodium hydroxide solution to pretreated material is 4:1 to 6:1.

[0029] The present invention is further configured such that the solid-liquid separation is completed by a plate and frame filter press under a pressure of 0.4-0.6 MPa.

[0030] The present invention is further configured such that the electrolyte temperature is maintained at 45-55°C during the electrolysis process, and the amount of solution returned for replenishment is 90%-95% of the amount of alkali consumed during electrolysis.

[0031] The present invention has the following beneficial effects:

[0032] 1. This invention employs a staged recovery process of "alkali leaching-purification-electrolysis-smelting," fully utilizing the differences in solubility of lead, zinc, and tin under alkaline conditions. Through a chemical stripping reactor, tin is selectively dissolved preferentially in the form of sodium stannate, while lead and zinc remain in the solid phase, achieving preliminary and efficient separation of tin from lead and zinc. Subsequently, the tin-containing liquid phase undergoes impurity purification and reduction treatment, utilizing hydrogen sulfide to selectively precipitate residual lead, zinc, and other impurity ions, significantly improving the purity of the electrolyte. Electrolysis on this basis yields high-purity metallic tin deposition. The solid residue is dried and smelted to obtain a lead-zinc alloy, achieving comprehensive recovery of valuable metals.

[0033] 2. This invention incorporates a solution circulation pipeline, returning the electrolyzed alkaline solution to the chemical stripping reactor as alkali replenishment, thus achieving the recycling of sodium hydroxide, significantly reducing the consumption of fresh alkali, and lowering raw material costs. Simultaneously, an online monitoring and adjustment device monitors the pH value of the returned solution in real time and automatically adjusts the replenishment flow rate, ensuring stable alkalinity in the reaction system and improving the stability and controllability of the process. Furthermore, the residue treatment unit utilizes the waste heat from the chemical stripping reactor to heat the drying kiln, achieving cascaded energy utilization, reducing system energy consumption, and embodying the circular economy concept of "reduction, reuse, and resource recovery."

[0034] 3. This invention uses alkaline leaching instead of traditional acidic leaching or pyrometallurgical processes, avoiding problems such as strong acid corrosion and the emission of harmful gases (such as SO2 and Cl2), making it environmentally friendly. The impurity purification process uses a mixed H2S / N2 gas, with nitrogen acting as a dilution gas to effectively control the H2S concentration, reducing the risk of toxic gas emissions. Furthermore, the generated sulfide precipitates can be centrally treated, preventing heavy metal ions from entering subsequent processes.

[0035] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0036] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 This is a schematic diagram of the distribution of the metal lead, zinc, and tin recycling system provided by the present invention.

[0038] The attached diagram lists the components represented by each number as follows:

[0039] 100. Feed pretreatment unit; 200. Chemical stripping reactor; 300. Solid-liquid separation device; 400. Impurity purification and reduction tank; 500. Electrolytic recovery tank; 600. Residue treatment unit; 700. Solution circulation pipeline; 800. Line monitoring and regulation device. Detailed Implementation

[0040] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0041] Example

[0042] Please see Figure 1 This invention relates to a metal lead, zinc, and tin recycling system, comprising:

[0043] The feed pretreatment unit 100 is used to crush, magnetically separate, and screen mixed metal materials containing lead, zinc, and tin to obtain pretreated materials with a particle size of less than 5 mm. This unit consists of a crusher, a magnetic separator, and a double-layer vibrating screen, and aims to provide homogeneous raw materials with suitable particle size and controllable impurities for subsequent chemical reactions. The crusher crushes large mixed metal materials into smaller particle sizes, increasing the specific surface area of ​​the material, which is beneficial to the mass transfer efficiency of subsequent chemical reactions. The magnetic separator is used to remove iron impurities that may be mixed in the material, avoiding interference from iron elements in the subsequent selective dissolution and electrolysis of tin. The double-layer vibrating screen precisely controls the particle size distribution of the material through two-stage screening (the upper screen mesh size is greater than 5 mm, and the lower screen mesh size is less than 5 mm), ensuring that the particle size of the material entering the chemical stripping reactor is less than 5 mm, which avoids incomplete reaction of excessively large particles and prevents excessively fine particles from generating dust or agglomerating, affecting the uniformity of the reaction.

[0044] A chemical stripping reactor 200, connected to the feed pretreatment unit 100, is used to contain a sodium hydroxide solution with a concentration of 80-120 g / L. The pretreated material is added to the reactor, and a chemical stripping reaction is carried out at a temperature of 85-95°C for 1.5-2.5 hours. This allows tin to enter the liquid phase in the form of sodium stannate, while lead and zinc remain in the solid phase. The reactor employs an alkaline leaching process for selectively dissolving tin. An S-shaped curved surface agitator is installed inside the reactor, with three sets of blades evenly distributed along the vertical axis. Each set contains four circumferentially distributed blades. This structure generates strong axial and radial flows, forming a uniform turbulent field, effectively preventing material sedimentation, enhancing solid-liquid contact, ensuring the uniformity of temperature and concentration in the reaction system, and improving the tin leaching rate. The reaction is carried out at 85-95°C and 80-120 g / L sodium hydroxide. Tin dissolves in the form of sodium stannate, while lead and zinc remain in the solid phase due to the formation of insoluble hydroxides or metallic forms, achieving preliminary separation of tin from lead and zinc.

[0045] The solid-liquid separation device 300 is connected to the chemical stripping reactor 200 and is used to separate the mixture after the chemical stripping reaction to obtain tin-containing filtrate and lead-zinc-containing filter residue. Through this device, the recovery of sodium stannate solution in the liquid phase and the collection of lead-zinc enrichment in the solid phase can be realized, providing independent material flows for subsequent electrolytic recovery of tin and smelting recovery of lead and zinc, avoiding cross-contamination, and improving the recovery purity and efficiency of each metal.

[0046] The impurity purification and reduction tank 400 is connected to the filtrate outlet of the solid-liquid separation device 300. It receives the tin-containing filtrate and introduces a mixture of hydrogen sulfide and nitrogen gas at a volume ratio of 1:4. The impurity purification and reduction reaction is carried out at 60-70℃ for 1-1.5 hours, causing lead and zinc impurity ions to precipitate as sulfides. This tank is used to purify lead, zinc, and other metallic impurity ions from the tin-containing filtrate. An annular gas distributor is installed at the top, and inclined through-holes are opened on its lower surface, allowing the hydrogen sulfide and nitrogen gas mixture to be ejected tangentially or obliquely, forming a swirling or uniform flow. The bubble distribution enhances the gas-liquid contact area and mass transfer efficiency, promoting the reaction of lead and zinc ions with sulfur ions to form lead sulfide and zinc sulfide precipitates. Simultaneously, a fixed bed carrier filled with supported catalyst particles is set in the tank. The catalyst can accelerate the sulfidation reaction kinetics, reduce the reaction activation energy, and improve the impurity removal efficiency and selectivity. Under the condition of 60-70℃, a mixed gas of H2S / N2 (volume ratio 1:4) is introduced for 1-1.5h. Nitrogen is used as a dilution gas to adjust the H2S concentration, avoiding over-sulfidation or the generation of too many sulfide colloids, and ensuring that the precipitated particles are easy to separate in subsequent processes.

[0047] An electrolytic recovery cell 500, connected to the impurity purification and reduction cell 400, is used to receive the purified tin-containing solution. It uses a stainless steel plate as the cathode and an iridium-tantalum coated titanium plate as the anode, operating at a DC voltage of 2.8-3.6V and a current density of 180-240A / m. 2 Electrolysis is performed under specific conditions, causing tin to deposit on the cathode surface. An insulating partition is placed between the cathode and anode, with its height 10-15 cm below the electrolyte level. This creates natural convection driven by the liquid level difference, promoting electrolyte circulation and simultaneously isolating oxygen generated in the anode area from direct contact with tin ions in the cathode area, preventing tin re-oxidation. The DC voltage is 2.8-3.6V, and the current density is 180-240A / m. 2 The parameter settings take into account both electrolysis efficiency and energy consumption; equipped with an automatic scraper device, it can periodically scrape off the metal tin deposited on the cathode surface, realizing continuous or semi-continuous production, avoiding manual operation, and improving the level of automation and production efficiency.

[0048] The residue treatment unit 600 is connected to the solid outlet of the solid-liquid separation device 300 and is used to dry and smelt the lead-zinc filter residue at high temperature to obtain a lead-zinc alloy. This unit processes the lead-zinc filter residue after solid-liquid separation and recovers the lead-zinc alloy through a drying kiln and a casting furnace. The drying kiln is heated by the waste heat recovery system of the chemical stripping reactor to achieve energy cascade utilization and reduce system energy consumption. The dried filter residue enters the casting furnace for high-temperature smelting. Due to their low melting points (lead 327℃, zinc 907℃), lead and zinc form an alloy melt, which is then cooled and cast into ingots to obtain the lead-zinc alloy product. This realizes the resource utilization of solid residue, avoids secondary pollution, and improves the overall metal recovery rate.

[0049] The solution circulation pipeline 700 connects the electrolyte outlet of the electrolytic recovery tank 500 to the alkali supply port of the chemical stripping reactor 200, and is used to return the electrolyzed solution to the chemical stripping reactor 200, thereby realizing the recycling of the electrolyzed solution (mainly containing sodium hydroxide), reducing the consumption of fresh alkali, and lowering operating costs.

[0050] An online monitoring and adjustment device 800 is installed on the solution circulation pipeline 700 to detect the pH value of the returned solution and adjust the replenishment flow rate. It detects the pH value of the returned solution in real time and automatically adjusts the replenishment flow rate (such as adding fresh alkali solution or dilution water) according to a set threshold to ensure that the concentration of alkali solution entering the chemical stripping reactor is stable within the range of 80-120 g / L. This closed-loop control system ensures the stability and continuity of the entire process.

[0051] In summary, the lead-zinc-tin metal recovery system provided in this embodiment is based on the goal of efficient, clean, and resource-based recovery of mixed lead-zinc-tin metal materials. Through multi-unit collaboration, physical-chemical coupling, process circulation, and intelligent control of the process flow, it achieves the step-by-step separation and high-value recovery of each metal component.

[0052] A recycling method for a lead-zinc-tin metal recycling system includes the following steps:

[0053] The mixed metal material containing lead, zinc and tin is subjected to crushing, magnetic separation and screening in sequence to obtain pretreated material with a particle size of less than 5 mm.

[0054] The pretreated material is added to a sodium hydroxide solution with a concentration of 80-120 g / L and stirred at 85-95°C for 1.5-2.5 h to perform chemical stripping and dissolve the tin.

[0055] The mixture after chemical stripping is subjected to solid-liquid separation to obtain tin-containing filtrate and lead-zinc-containing filter residue; a mixture of hydrogen sulfide and nitrogen gas with a volume ratio of 1:4 is introduced into the tin-containing filtrate and reacted at 60-70℃ for 1-1.5h to purify and reduce impurities, causing lead and zinc impurities to precipitate.

[0056] The purified tin-containing solution was subjected to liquid-solid separation to obtain a purified solution; the purified solution was then subjected to a DC voltage of 2.8-3.6V and a current density of 180-240A / m. 2 Electrolysis is performed under specific conditions, during which tin is reduced and deposited on the cathode surface. The electrolyzed solution is then returned to the chemical stripping process as alkali replenishment, during which the pH value of the solution is monitored and the flow rate is adjusted.

[0057] The deposited metallic tin on the cathode surface is scraped off and collected; the lead-zinc filter residue is dried and smelted at high temperature to obtain a lead-zinc alloy.

[0058] In the chemical stripping reaction, the liquid-solid mass ratio of sodium hydroxide solution to pretreated material is 4:1 to 6:1; the solid-liquid separation is completed by plate and frame filter press under a pressure of 0.4-0.6 MPa; the electrolyte temperature is maintained at 45-55℃ during the electrolysis process, and the amount of solution returned for replenishment is 90%-95% of the amount of alkali consumed in the electrolysis.

[0059] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0060] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A metal lead, zinc, and tin recycling system, characterized in that, include: The feed pretreatment unit (100) is used to crush, magnetically separate and screen mixed metal materials containing lead, zinc and tin to obtain pretreated materials with a particle size of less than 5 mm. A chemical stripping reactor (200) is connected to the feed pretreatment unit (100) for containing a sodium hydroxide solution with a concentration of 80-120 g / L, and adding the pretreated material therein, and carrying out a chemical stripping reaction at a temperature of 85-95°C for 1.5-2.5 h, so that tin enters the liquid phase in the form of sodium stannate, while lead and zinc remain in the solid phase; A solid-liquid separation device (300) is connected to the chemical stripping reactor (200) and is used to separate the mixture after the chemical stripping reaction to obtain a tin-containing filtrate and a lead-zinc-containing filter residue. The impurity purification and reduction tank (400) is connected to the filtrate outlet of the solid-liquid separation device (300) to receive the tin-containing filtrate and to introduce a mixed gas of hydrogen sulfide and nitrogen with a gas volume ratio of 1:

4. The impurity purification and reduction reaction is carried out at 60-70℃ for 1-1.5h to precipitate lead and zinc impurity ions in the form of sulfides. An electrolytic recovery cell (500), connected to the impurity purification and reduction cell (400), is used to receive the purified tin-containing solution. It uses a stainless steel plate as the cathode and an iridium-tantalum coated titanium plate as the anode, operating at a DC voltage of 2.8-3.6V and a current density of 180-240A / m. 2 Electrolysis is performed under certain conditions to deposit tin on the cathode surface; The residue treatment unit (600) is connected to the solid outlet of the solid-liquid separation device (300) and is used to dry and smelt the lead-zinc filter residue at high temperature to obtain a lead-zinc alloy. A solution circulation pipeline (700) is connected to the electrolyte outlet of the electrolytic recovery tank (500) and the alkali supply port of the chemical stripping reactor (200) for returning the electrolyzed solution to the chemical stripping reactor (200); An online monitoring and adjustment device (800) is installed on the solution circulation pipeline (700) to detect the pH value of the returned solution and adjust the replenishment flow rate.

2. The metal lead-zinc-tin recovery system according to claim 1, characterized in that, The stirring in the chemical stripping reactor (200) is achieved by an S-shaped curved surface stirring paddle. The stirring paddle is arranged in three groups at equal intervals along the vertical axis, and each group contains four blades evenly distributed along the circumference.

3. The metal lead-zinc-tin recovery system according to claim 1, characterized in that, The impurity purification and reduction tank (400) is provided with an annular gas distributor at the top, and the lower surface of the gas distributor is provided with an inclined through hole for uniformly releasing reducing gas.

4. The metal lead-zinc-tin recovery system according to claim 1, characterized in that, An insulating partition is provided between the cathode plate and the anode plate in the electrolytic recovery tank (500), and the height of the insulating partition is 10-15 cm lower than the electrolyte surface.

5. A metal lead-zinc-tin recycling system according to claim 1, characterized in that, The feed pretreatment unit (100) includes a crusher, a magnetic separator and a double-layer vibrating screen, and the residue treatment unit (600) includes a drying kiln and a melting furnace. The heat source of the drying kiln comes from the waste heat recovery system of the chemical stripping reactor (200).

6. A metal lead-zinc-tin recovery system according to claim 1, characterized in that, The impurity purification and reduction tank (400) is equipped with a fixed bed carrier filled with supported catalyst particles, and the electrolytic recovery tank (500) is equipped with an automatic scraper device.

7. The recovery method of the lead-zinc-tin metal recovery system according to any one of claims 1-6, characterized in that, Includes the following steps: The mixed metal material containing lead, zinc and tin is subjected to crushing, magnetic separation and screening in sequence to obtain pretreated material with a particle size of less than 5 mm. The pretreated material is added to a sodium hydroxide solution with a concentration of 80-120 g / L and stirred at 85-95°C for 1.5-2.5 h to perform chemical stripping and dissolve the tin. The mixture after chemical stripping is subjected to solid-liquid separation to obtain tin-containing filtrate and lead-zinc-containing filter residue; a mixture of hydrogen sulfide and nitrogen gas with a volume ratio of 1:4 is introduced into the tin-containing filtrate and reacted at 60-70℃ for 1-1.5h to purify and reduce impurities, causing lead and zinc impurities to precipitate. The purified tin-containing solution was subjected to liquid-solid separation to obtain a purified solution; the purified solution was then subjected to a DC voltage of 2.8-3.6V and a current density of 180-240A / m. 2 Electrolysis is performed under certain conditions, and tin is reduced and deposited on the cathode surface; The electrolyzed solution is returned to the chemical stripping process as alkali replenishment. During the replenishment process, the pH value of the solution is monitored and the flow rate is adjusted. Scrape off the deposited metallic tin on the cathode surface and collect it; Lead-zinc alloy is obtained by drying and high-temperature smelting the lead-zinc filter residue.

8. The recycling method of the lead-zinc-tin metal recycling system according to claim 7, characterized in that, In the chemical stripping reaction, the liquid-solid mass ratio of sodium hydroxide solution to pretreated material is 4:1 to 6:

1.

9. The recycling method of the lead-zinc-tin metal recycling system according to claim 7, characterized in that, The solid-liquid separation is completed by a plate and frame filter press under a pressure of 0.4-0.6 MPa.

10. The recycling method of the lead-zinc-tin metal recycling system according to claim 7, characterized in that, During the electrolysis process, the electrolyte temperature is maintained at 45-55℃, and the amount of solution returned for replenishment is 90%-95% of the amount of alkali consumed in the electrolysis.

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