Regeneration treatment method for waste tin stripping water

Abstract

The invention discloses a waste tin stripping water regeneration treatment method which comprises the following steps: adding waste tin stripping water into a reaction kettle, stirring, controlling the temperature, adding a settling agent, reacting, and carrying out solid-liquid separation to obtain tin precipitation mother liquor and tin sludge; adding an acidic precipitant into the tin immersion mother liquor for reaction, and then carrying out solid-liquid separation to obtain acidic salt of copper and tin stripping aqueous solution; performing solid-liquid separation on the tin mud after the tin mud is subjected to chemical washing treatment to obtain pretreated tin mud and washing filtrate; hydrochloric acid is added into the dissolving kettle to be stirred, the pretreated tin mud is added for a heat-preservation leaching reaction, and acid leaching liquid is obtained; and performing a double-membrane electrolytic reaction by taking the acid leaching solution as a cathode reaction solution of a cathode chamber, a dilute sulfuric acid solution as an anode reaction solution of an anode chamber and a dilute hydrochloric acid solution as an intermediate reaction solution of an intermediate chamber to obtain metal tin and a ferrous chloride solution in the cathode chamber, a hydrochloric acid solution in the intermediate chamber and oxygen generated in the anode chamber. According to the method, high-valued comprehensive utilization of valuable resources in the waste tin stripping water is realized, and the treatment cost of the waste tin stripping water is effectively reduced.

Description

Technical Field

[0001] The present application relates to the technical field of waste liquid treatment, and in particular to a method for regenerating waste tin stripping water. Background Art

[0002] In the process of printed circuit board manufacturing, a large amount of nitric acid type waste tin stripping water will be produced. The waste tin stripping water contains a large amount of nitric acid, metal ions such as tin, copper, and iron, and a small amount of organic waste such as polymer surfactants. It can be seen that the composition of the waste tin stripping water is very complex and the processing difficulty is relatively large. At present, the treatment methods of waste tin stripping water in the prior art mainly include neutralization method, recycling method, etc., and the recycling method includes distillation recovery method, acid precipitation method, diffusion dialysis-electrodeposition method, electrolysis-precipitation method and membrane treatment method, etc. Among them, the neutralization method is to directly add alkaline substances such as lime, ammonia, sodium carbonate, liquid caustic soda, etc. to the waste tin stripping water to adjust the pH value to precipitate the metal ions. The method has a simple processing procedure, but the alkali consumption is large, and the valuable resources such as acids and additives are wasted. The resource utilization effect is not ideal, and a large amount of high-salt wastewater will be produced, resulting in a substantial increase in the subsequent wastewater treatment cost, and the metastannic acid obtained by neutralization is in colloidal form, with fine particles and viscous, and the production efficiency is greatly affected. At the same time, the impurity metal ions are co-precipitated into the tin mud, and the grade of the tin mud is low, and the subsequent deep processing is difficult. The distillation method uses negative pressure distillation to evaporate the nitric acid in the waste tin stripping water, then cool it and recover the dilute nitric acid solution, which can be used again for the preparation of tin-containing sub-liquid. The remaining weakly acidic waste tin stripping water is neutralized with liquid alkali to recover metal ions. Due to the strong corrosiveness of nitric acid, this method has high requirements for equipment and the recovered nitric acid concentration is low. The acid precipitation method is to add metal ion precipitants and flocculants to the waste tin stripping water to separate the tin, copper and other metals in it. The clear liquid can be used as a regenerated tin stripping liquid by adding appropriate components. This method does not effectively separate and recover the tin and copper in the waste tin stripping water, and the resource utilization rate is low. The diffusion dialysis method is to add waste tin stripping water and clean water on both sides of the diffusion permeation membrane, respectively, and use the concentration difference on both sides as the power to achieve the separation of nitric acid. The recovery rate of nitric acid reaches more than 70%, and the remaining solution is recovered by ion exchange membrane electrolysis. The process equipment involved in this method is complex, especially the durability of the permeation membrane and ion membrane is difficult to guarantee, and the maintenance and replacement costs are high, resulting in the process. The economic benefits are not obvious. The solvent extraction method is to extract and separate the nitric acid in the waste tin stripping water based on the selection of suitable extractants, and then recover the cathode copper through electrolysis of the remaining solution. This process can recover most of the nitric acid and copper, but the process is complicated, the extraction and precipitation steps require the consumption of a large amount of reagents, and the processing cost is relatively high. Summary of the invention

[0003] Based on this, it is necessary to provide a method for regenerating and treating waste tin stripping water. The method for regenerating and treating waste tin stripping water of the present invention can realize the efficient recycling of valuable metals in waste tin stripping water, make full use of the effective tin stripping components contained in the waste tin stripping water itself, regenerate it into a tin stripping water sub-liquid product for reuse in the circuit board manufacturing industry, realize the efficient recycling of waste tin stripping water, and reduce the emission of pollutants.

[0004] An embodiment of the present application provides a method for regenerating waste tin stripping water.

[0005] A method for regenerating waste tin stripping water, comprising the following steps:

[0006] Adding waste tin stripping water into a reactor, stirring and controlling the temperature, adding a precipitation aid to the waste tin stripping water, reacting, and then separating the solid and liquid to obtain a tin precipitation mother liquor and tin mud;

[0007] Adding an acidic precipitant to the tin precipitation mother liquor to react and then separating the solid and liquid to obtain an acid salt of copper and a tin stripping liquid;

[0008] The tin mud is subjected to slurry washing treatment and then solid-liquid separation to obtain pre-treated tin mud and washing filtrate;

[0009] Adding hydrochloric acid into a dissolving kettle, adding pretreated tin mud into the hydrochloric acid to carry out heat preservation leaching reaction until the tin mud is completely dissolved to obtain an acid leaching solution containing at least tin tetrachloride and ferric chloride;

[0010] The acid leaching solution is used as the cathode reaction solution of the cathode chamber, the dilute sulfuric acid solution is used as the anode reaction solution of the anode chamber, and the dilute hydrochloric acid solution is used as the intermediate reaction solution of the intermediate chamber to carry out a double-membrane electrolysis reaction, thereby obtaining a metallic tin and ferrous chloride solution located in the cathode chamber, a hydrochloric acid solution located in the intermediate chamber, and oxygen generated in the anode chamber.

[0011] In some embodiments, when adding waste tin stripping water into a reactor, stirring and controlling the temperature, the following steps are included:

[0012] The waste tin stripping water is heated by one or more methods including coil, jacket and steam, and the temperature is controlled to 85℃~120℃.

[0013] In some embodiments, the precipitation aid includes oxalic acid, and the precipitation aid is added to the waste tin stripping water for reaction and then solid-liquid separation is performed to obtain a tin precipitation mother liquor and tin mud, which includes the following steps: adding oxalic acid to the waste tin stripping water, keeping the reaction warm for 1h~2h, and then separating the solid and liquid to obtain a tin precipitation mother liquor and tin mud, wherein the mass volume ratio of the added amount of oxalic acid to the waste tin stripping water is (1kg~5kg): 1m 3 .

[0014] In some embodiments, the precipitation aid includes hydrogen peroxide and sulfuric acid. When the precipitation aid is added to the waste tin stripping water for reaction and then solid-liquid separation is performed to obtain a tin precipitation mother liquor and tin mud, the following steps are included: 27.5wt% hydrogen peroxide and 98wt% sulfuric acid are added to the waste tin stripping water, and the solid-liquid separation is performed after the reaction is kept warm for 2h~4h to obtain a tin precipitation mother liquor and tin mud, wherein the volume ratio of the hydrogen peroxide, the sulfuric acid, and the waste tin stripping water is (0.01~0.05):(0.005~0.01):1.

[0015] In some embodiments, the waste tin stripping water regeneration treatment method meets at least one of the following conditions:

[0016] (1) When an acidic precipitant is added to the tin precipitation mother solution, the amount of the acidic precipitant added is 2.5 to 3 times the total copper mass in the tin precipitation mother solution;

[0017] (2) The reaction time of adding an acidic precipitant to the tin precipitation mother solution is 1 h to 2 h;

[0018] (3) The acidic precipitant includes 99 wt % oxalic acid, and the acidic salt of copper obtained is copper oxalate;

[0019] (4) The tin stripping water sub-liquid can be used to regenerate tin stripping water.

[0020] In some embodiments, the waste tin stripping water regeneration treatment method meets at least one of the following conditions:

[0021] (1) when adding the pretreated tin mud to the hydrochloric acid for heat preservation leaching reaction, the amount of hydrochloric acid added is 1 to 1.5 times the stoichiometric amount required for complete dissolution of tin and iron in the pretreated tin mud,

[0022] (2) The temperature during the heat preservation leaching reaction is 95℃~105℃.

[0023] In some of the embodiments, a double-membrane electrolyzer is used for double-membrane electrolysis reaction, and the double-membrane electrolyzer includes an anode chamber, an intermediate chamber and a cathode chamber, a cation exchange membrane is provided between the anode chamber and the intermediate chamber for separation, an anion exchange membrane is provided between the cathode chamber and the intermediate chamber for separation, a titanium plate or a graphite plate coated with a precious metal is provided in the anode chamber as a positive electrode, and a titanium plate or a copper plate is provided in the cathode chamber as a negative electrode.

[0024] In some embodiments, the waste tin stripping water regeneration treatment method meets at least one of the following conditions:

[0025] (1) The mass concentration of dilute sulfuric acid in the anode chamber is 1wt%~2wt%;

[0026] (2) The mass concentration of the dilute hydrochloric acid in the intermediate chamber is 0.2wt%~0.5wt%.

[0027] In some embodiments, the tin sludge is subjected to slurry washing treatment, comprising the following steps:

[0028] Add water to the pulping kettle, wherein the amount of water added is 3 to 5 times the mass of the tin mud, stir at a speed of 40 Hz to 50 Hz, add the tin mud for slurry washing for 2 h to 4 h, and then separate the solid and liquid to obtain the pretreated tin mud and the washing filtrate.

[0029] In some embodiments, the waste tin stripping water regeneration treatment method meets at least one of the following conditions:

[0030] (1) The washing filtrate enters the wastewater station system for treatment to recover copper mud;

[0031] (2) The hydrochloric acid solution obtained in the intermediate chamber is used as a raw material source for the heat preservation leaching reaction;

[0032] (3) The oxygen generated in the anode chamber is used to oxidize the ferrous chloride solution generated in the cathode chamber to obtain a ferric chloride solution.

[0033] The above-mentioned waste tin stripping water regeneration treatment method takes the hazardous waste waste tin stripping water generated by the electronic information industry as the research object, realizes the efficient recovery and utilization of valuable metals in the waste tin stripping water, and obtains products such as metallic tin, copper acid salts, and ferric chloride solutions; the present application makes full use of the effective tin stripping components contained in the waste tin stripping water itself, regenerates it into a tin stripping water sub-liquid product for reuse in the circuit board manufacturing industry, realizes the efficient recycling of waste tin stripping water, and reduces the discharge of pollutants. The pollutants in the waste tin stripping water generated in the manufacturing process of printed circuit boards mainly include: tin content 50g / L~150g / L, copper content 5g / L~20g / L, iron content 10g / L~15g / L, nitric acid content 15wt%~20wt%. The waste tin stripping water regeneration treatment method of the present application can recycle the waste tin stripping water generated in the manufacturing process of printed circuit boards at a high value.

[0034] Compared with the traditional technology, the waste tin stripping water regeneration treatment method of the present application has the following technical effects.

[0035] (1) The waste tin stripping water regeneration treatment method is applicable to the regeneration treatment of nitric acid type waste tin stripping water.

[0036] (2) A small amount of precipitation aid is added in the waste tin stripping water regeneration treatment method, which realizes the effective separation and recovery of tin and copper in the waste tin stripping water. The recovered tin sludge has a high grade and the dry basis tin content can reach more than 60wt%. The metallic tin obtained by electrolytic treatment has a tin content of more than 98wt%.

[0037] (3) Use acidic precipitants such as oxalic acid to recover copper from the tin-stripping mother liquor. Oxalic acid will not destroy the tin-stripping components in the tin-stripping mother liquor, thus realizing the recycling and reuse of waste tin-stripping water.

[0038] (4) This application can realize the high-value comprehensive utilization of valuable resources in waste tin stripping water and effectively reduce the cost of waste tin stripping water treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application, and those skilled in the art can obtain other drawings based on these drawings without creative work.

[0040] In order to more completely understand the present application and its beneficial effects, the following description will be given in conjunction with the accompanying drawings. In the following description, the same reference numerals represent the same parts.

[0041] FIG1 is a schematic flow chart of a method for regenerating waste tin stripping water according to an embodiment of the present invention. DETAILED DESCRIPTION

[0042] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0043] In the description of the present invention, "several" means more than one, "many" means more than two, "greater than", "less than", "exceed", etc. are understood to exclude the number itself, and "above", "below", "within", etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0044] In this article, "optionally", "optional", "optional" means optional, that is, it means to be selected from any of the two parallel solutions of "yes" or "no". If there are multiple "optional" in a technical solution, unless otherwise specified and there is no contradiction or mutual restriction, each "optional" is independent. In this application, the descriptions such as "optionally contain" and "optionally include" mean "contain or not contain".

[0045] In the present invention, unless otherwise stated, the sum of the parts of each component in the composition can be 100 parts by weight. Unless otherwise specified, the basis of the percentages (including weight percentages) of the present invention is the total weight of the composition. In addition, "wt%" herein means mass percentage, and "at%" means atomic percentage.

[0046] In this article, unless otherwise stated, each reaction step may be carried out in the order described herein or may not be carried out in the order described herein. For example, other steps may be included between each reaction step, and the order of the reaction steps may also be appropriately swapped. This can be determined by the technician based on common knowledge and experience. Preferably, the reaction method herein is carried out sequentially.

[0047] In the present application, when it comes to a numerical interval (i.e., a numerical range), unless otherwise specified, the distribution of the optional numerical values ​​in the numerical interval is considered to be continuous, and includes the two numerical endpoints (i.e., the minimum and maximum values) of the numerical interval, and each numerical value between the two numerical endpoints. Unless otherwise specified, when the numerical interval only refers to an integer in the numerical interval, it includes the two endpoint integers of the numerical range, and each integer between the two endpoints, which is equivalent to directly listing each integer. When multiple numerical ranges are provided to describe features or characteristics, these numerical ranges can be combined. In other words, unless otherwise specified, the numerical range disclosed in the present application should be understood to include any and all sub-ranges included therein. The "numerical value" in the numerical interval can be any quantitative value, such as a number, a percentage, a ratio, etc. "Numerical interval" allows for a broad range of quantitative intervals such as percentage intervals, ratio intervals, and ratio intervals.

[0048] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0049] The present application provides a method for regenerating and treating waste tin stripping water to solve at least one of the following technical problems in the prior art for treating waste tin stripping water: (1) The neutralization method consumes a large amount of alkali, which wastes valuable resources such as acids and additives, and the resource utilization effect is not ideal. It will also produce a large amount of high-salt wastewater, which will greatly increase the subsequent wastewater treatment cost. In addition, the metastannic acid obtained by neutralization is in a colloidal form with fine particles and a viscous state, which greatly affects the production efficiency. At the same time, the impurity metal ions co-precipitate into the tin mud, and the grade of the tin mud is low, making subsequent deep processing difficult. (2) The distillation method has high requirements for equipment, and the concentration of recovered nitric acid is low. (3) The acid precipitation method does not effectively separate and recover the tin and copper in the waste tin stripping water, and the resource utilization rate is low. (4) The process equipment involved in the diffusion dialysis method is complex, especially the durability of the permeable membrane and the ion membrane is difficult to guarantee, and the maintenance and replacement costs are high, resulting in the economic benefits of the process being not obvious. (5) The solvent extraction method has a complex process, and the extraction and precipitation processes require a large amount of reagents, and the treatment cost is relatively high. The following will illustrate the method for regenerating waste tin stripping water with the help of the accompanying drawings.

[0050] The waste tin stripping water regeneration treatment method provided in the embodiment of the present application is illustratively shown in Figure 1. Figure 1 is a schematic flow chart of the waste tin stripping water regeneration treatment method provided in the embodiment of the present application. The waste tin stripping water regeneration treatment method of the present application is suitable for the purpose of waste tin stripping water regeneration treatment, and efficiently recycles the valuable metals in the waste tin stripping water, fully utilizes the effective tin stripping components contained in the waste tin stripping water itself, regenerates it into a tin stripping water sub-liquid product for reuse in the circuit board manufacturing industry, realizes the efficient recycling of waste tin stripping water, and reduces the emission of pollutants. For example, the waste tin stripping water regeneration treatment method of the present application is suitable for the purpose of regenerating nitric acid type waste tin stripping water.

[0051] In order to more clearly illustrate the process of the waste tin stripping water regeneration treatment method, the waste tin stripping water regeneration treatment method will be introduced below in conjunction with the accompanying drawings.

[0052] Exemplarily, a method for regenerating waste tin stripping water comprises the following steps:

[0053] The waste tin stripping water is added into the reactor for stirring and temperature control, and a precipitation aid is added into the waste tin stripping water for reaction and solid-liquid separation is performed to obtain a tin precipitation mother liquor and tin mud.

[0054] An acidic precipitant is added to the tin precipitation mother liquor to react and then solid-liquid separation is performed to obtain copper acid salt and tin stripping sub-liquid.

[0055] The tin mud is subjected to slurry washing treatment and then solid-liquid separation is performed to obtain pre-treated tin mud and washing filtrate.

[0056] Add hydrochloric acid into the dissolving kettle and stir, add the pretreated tin mud into the hydrochloric acid to carry out heat preservation leaching reaction until the tin mud is completely dissolved, and obtain an acid leaching solution containing at least tin tetrachloride and ferric chloride.

[0057] A double-membrane electrolysis reaction is carried out using an acid leaching solution as a cathode reaction solution in a cathode chamber, a dilute sulfuric acid solution as an anode reaction solution in an anode chamber, and a dilute hydrochloric acid solution as an intermediate reaction solution in an intermediate chamber to obtain a metallic tin and ferrous chloride solution in the cathode chamber, a hydrochloric acid solution in the intermediate chamber, and oxygen generated in the anode chamber.

[0058] The above-mentioned waste tin stripping water regeneration treatment method takes the hazardous waste waste tin stripping water generated by the electronic information industry as the research object, realizes the efficient recovery and utilization of valuable metals in the waste tin stripping water, and prepares products such as metallic tin, copper acid salts, ferric chloride solution, etc.; this application makes full use of the effective tin stripping components contained in the waste tin stripping water itself, regenerates it into a tin stripping water sub-liquid product for reuse in the circuit board manufacturing industry, realizes the efficient recycling of waste tin stripping water, and reduces the emission of pollutants.

[0059] In some embodiments, when adding waste tin stripping water to a reactor for stirring and temperature control, the following steps are included: heating the waste tin stripping water by one or more methods including coils, jackets and steam, and controlling the temperature to 85°C to 120°C. The purpose of reaction temperature control includes (1) promoting the conversion of α-stannic acid to β-stannic acid and accelerating the aggregation and sedimentation of β-stannic acid. The reaction temperature should not be too high or too low. When the reaction temperature is too high, energy consumption increases and a large amount of acid mist will be generated and needs to be treated; when the reaction temperature is too low, the conversion of α-stannic acid is incomplete and the tin precipitation effect is poor.

[0060] In some embodiments, the precipitation aid includes oxalic acid, and the oxalic acid can be 99wt% oxalic acid. When the precipitation aid is added to the waste tin stripping water for reaction and then solid-liquid separation is performed to obtain the tin precipitation mother liquor and tin mud, the steps include: adding oxalic acid to the waste tin stripping water, keeping the temperature for reaction for 1h~2h, and then solid-liquid separation to obtain the tin precipitation mother liquor and tin mud, wherein the mass volume ratio of the added amount of oxalic acid to the waste tin stripping water is (1kg~5kg): 1m 3 . The addition of oxalic acid can promote the transformation of α-stannic acid into β-stannic acid, accelerate the aggregation and sedimentation of β-stannic acid, and react with the incompletely converted α-stannic acid to generate precipitate for recovery. The amount of oxalic acid added should not be too much or too little. When the amount of oxalic acid added is too much, it will react with the copper in the waste tin stripping water to generate a large amount of copper oxalate, which will co-precipitate with tin, affecting the quality of the tin mud, making the subsequent separation of copper and tin difficult and the resource utilization rate low; when the amount of oxalic acid added is too little, part of the tin in the waste tin stripping water cannot be recycled, and the tin recovery rate is low.

[0061] In some embodiments, the precipitation aid includes hydrogen peroxide and sulfuric acid, and the precipitation aid is added to the waste tin stripping water for reaction and solid-liquid separation to obtain the tin precipitation mother liquor and tin mud includes the following steps: adding 27.5wt% hydrogen peroxide and 98wt% sulfuric acid to the waste tin stripping water, and separating the solid and liquid after heat preservation reaction for 2h~4h to obtain the tin precipitation mother liquor and tin mud, wherein the volume ratio of hydrogen peroxide, sulfuric acid, and waste tin stripping water is (0.01~0.05): (0.005~0.01): 1. The addition of hydrogen peroxide and sulfuric acid can jointly promote the conversion of α-stannic acid into β-stannic acid, accelerate the aggregation and sedimentation of β-stannic acid, and improve the recovery rate of tin. The addition amount of hydrogen peroxide and sulfuric acid should not be too much or too little. Excessive addition of hydrogen peroxide and sulfuric acid wastes raw materials, increases costs, and affects the quality of subsequent tin stripping water sub-liquid; too little addition of hydrogen peroxide and sulfuric acid leads to poor tin precipitation effect.

[0062] In some embodiments, when an acidic precipitant is added to the tin-immersion mother liquor, the amount of the acidic precipitant added is 2.5 to 3 times the total copper mass in the tin-immersion mother liquor. The acidic precipitant can precipitate and recover copper without destroying the effective tin-stripping components in the tin-immersion mother liquor. The amount of the acidic precipitant added should not be too much or too little. When the amount of the acidic precipitant added is too much, raw materials are wasted and the cost is high; when the amount of the acidic precipitant added is too little, the copper precipitation effect is poor and the copper recovery rate is low.

[0063] In some embodiments, the reaction time of adding the acidic precipitant to the tin precipitation mother solution is 1 h to 2 h.

[0064] In some of these embodiments, the acidic precipitant comprises 99 wt % oxalic acid.

[0065] In some of the embodiments, the tin stripping water sub-liquid can be used to regenerate the tin stripping water.

[0066] In some embodiments, when pretreated tin mud is added to hydrochloric acid for heat preservation leaching reaction, the amount of hydrochloric acid added is 1 to 1.5 times the stoichiometric amount required for complete dissolution of tin and iron in the pretreated tin mud. Controlling the amount of hydrochloric acid added can ensure complete leaching of tin and iron resources in the tin mud. The amount of hydrochloric acid added should not be too much or too little. When the amount of hydrochloric acid added is too much, raw materials are wasted and production costs are increased; when the amount of hydrochloric acid added is too little, the leaching of tin and iron resources in the tin mud is incomplete, and the recovery rate of tin and iron is low.

[0067] In some embodiments, the temperature during the heat preservation leaching reaction is 95° C. to 105° C. When the temperature during the heat preservation leaching reaction is 95° C. to 105° C., the dissolution of the tin mud can be promoted. The temperature during the heat preservation leaching reaction should not be too high or too low. If the temperature during the heat preservation leaching reaction is too high, the energy consumption will increase, and a large amount of acid mist will be generated and need to be treated; if the temperature during the heat preservation leaching reaction is too low, the tin mud leaching effect is poor.

[0068] In some of the embodiments, a double-membrane electrolyzer is used for double-membrane electrolysis reaction, and the double-membrane electrolyzer includes an anode chamber, an intermediate chamber and a cathode chamber. A cation exchange membrane is provided between the anode chamber and the intermediate chamber for separation, and an anion exchange membrane is provided between the cathode chamber and the intermediate chamber for separation. A titanium plate or a graphite plate coated with a precious metal is provided in the anode chamber as a positive electrode, and a titanium plate or a copper plate is provided in the cathode chamber as a negative electrode.

[0069] In some of the embodiments, the mass concentration of the dilute sulfuric acid in the anode chamber is 1 wt % to 2 wt %.

[0070] In some of the embodiments, the mass concentration of the dilute hydrochloric acid in the intermediate chamber is 0.2wt%~0.5wt%.

[0071] In some embodiments, the slurry washing treatment of the tin mud includes the following steps:

[0072] Add water to the pulping kettle, wherein the amount of water added is 3 to 5 times the mass of the tin mud, stir at a speed of 40 Hz to 50 Hz, add the tin mud for slurry washing for 2 hours to 4 hours, and separate the solid and liquid to obtain the pre-treated tin mud and the washing filtrate. Preferably, the above-mentioned water can be pure water, tap water, etc. The addition of water can wash away the copper entrained in the tin mud, improve the subsequent electrolysis efficiency and the quality of the metallic tin product. The amount of water added should not be too much or too little. If the amount of water added is too much, the pressure of subsequent wastewater treatment will increase; when the amount of water added is too little, the washing effect of the tin mud is poor.

[0073] In some of the embodiments, please refer to FIG. 1 , the washing filtrate enters the wastewater station system for treatment to recover the copper sludge.

[0074] In some of the embodiments, the hydrochloric acid solution obtained in the intermediate chamber is used as a raw material source for the thermal insulation leaching reaction.

[0075] In some of the embodiments, the oxygen generated in the anode chamber is used to oxidize the ferrous chloride solution generated in the cathode chamber to obtain a ferric chloride solution.

[0076] This embodiment provides a method for regenerating waste tin stripping water for treating waste tin stripping water. The waste tin stripping water used in this embodiment was tested to have the following component contents / concentrations: tin content 90 g / L, copper ion content 13 g / L, iron ion content 11 g / L, and nitric acid residue 20 wt%.

[0077] Example 1

[0078] A method for regenerating waste tin stripping water, as shown in FIG1 , comprises the following steps:

[0079] S11, volume is 10m 3 Add 8m3 of volume into the reactor3 The waste tin stripping water was stirred, steam was introduced to raise the temperature to 85°C, and 40 kg of 99 wt% oxalic acid, a precipitation aid, was added to the waste tin stripping water. The mass volume ratio of oxalic acid added to the waste tin stripping water was 5 kg: 1 m 3 After 2 hours of heat preservation reaction, the solid and liquid were separated to obtain tin precipitation mother liquor and tin mud. The dry tin content of the tin mud was 61.16wt%, and the residual tin content in the tin precipitation mother liquor was 311mg / L.

[0080] S12. Add 99wt% oxalic acid (2.5 times the total copper mass in the tin-stripping mother liquor) to the tin-stripping mother liquor, react for 1 hour, and then perform solid-liquid separation to obtain copper oxalate and tin-stripping sub-liquid. The residual copper content in the tin-stripping sub-liquid is 3.8g / L.

[0081] S13. Add water to the pulping kettle, wherein the amount of water added is 3 times the mass of the tin mud, stir at a speed of 40 Hz, add the tin mud for slurry washing for 2 hours, separate the solid and liquid to obtain the pretreated tin mud and the washing filtrate, and the washing filtrate enters the wastewater station system for treatment to recover the copper mud.

[0082] S14, add hydrochloric acid in an amount 1 times the stoichiometric amount required to completely dissolve the tin and iron in the pretreated tin mud into the dissolving kettle, start stirring, add the pretreated tin mud into the hydrochloric acid to carry out a leaching reaction at 95° C., and keep the temperature until the tin mud is completely dissolved, to obtain an acid leaching solution containing tin tetrachloride and ferric chloride.

[0083] S15. Configure a double-membrane electrolyzer, which includes an anode chamber, an intermediate chamber and a cathode chamber. A cation exchange membrane is provided between the anode chamber and the intermediate chamber for separation, and an anion exchange membrane is provided between the cathode chamber and the intermediate chamber for separation. A titanium plate or a graphite plate coated with a precious metal is provided in the anode chamber as a positive electrode, and a titanium plate or a copper plate is provided in the cathode chamber as a negative electrode.

[0084] S16, using acid leaching solution as the cathode reaction solution of the cathode chamber, using dilute sulfuric acid solution as the anode reaction solution of the anode chamber, and using dilute hydrochloric acid solution as the intermediate reaction solution of the intermediate chamber for double membrane electrolysis reaction, the mass concentration of dilute sulfuric acid in the anode chamber is 2wt%, and the mass concentration of dilute hydrochloric acid in the intermediate chamber is 0.5wt%. The cathode chamber electrode produces metallic tin with a purity of 98.86wt%, and the electrolytic residual solution is ferrous chloride solution, which is oxidized with the oxygen produced in the anode chamber to obtain ferric chloride solution, and the hydrochloric acid solution produced in the intermediate chamber is used as a raw material source for the heat preservation leaching reaction.

[0085] Example 2

[0086] A method for regenerating waste tin stripping water, as shown in FIG1 , comprises the following steps:

[0087] S21, volume is 10m 3 Add 8m3 of volume into the reactor3 The waste tin stripping water was stirred, steam was introduced to raise the temperature to 100°C, and 8 kg of 99 wt% oxalic acid, a precipitation aid, was added to the waste tin stripping water. The mass volume ratio of oxalic acid added to the waste tin stripping water was 1 kg:1 m 3 After 2 hours of heat preservation reaction, the solid and liquid were separated to obtain tin precipitation mother liquor and tin mud. The dry tin content of the tin mud was 62.05wt%, and the residual tin content in the tin precipitation mother liquor was 617mg / L.

[0088] S22. Add 99wt% oxalic acid (3 times the mass of total copper in the tin precipitation mother liquor) to the tin precipitation mother liquor, react for 1 hour, and then perform solid-liquid separation to obtain copper oxalate and tin stripping liquid. The residual copper content in the tin stripping liquid is 2.3g / L.

[0089] S23. Add water to the pulping kettle, wherein the amount of water added is 5 times the mass of the tin mud, stir at a speed of 40 Hz, add the tin mud for slurry washing for 4 hours, separate the solid and liquid to obtain the pretreated tin mud and the washing filtrate, and the washing filtrate enters the wastewater station system for treatment to recover the copper mud.

[0090] S24, add hydrochloric acid in an amount 1 times the stoichiometric amount required to completely dissolve the tin and iron in the pretreated tin mud into the dissolving kettle, start stirring, add the pretreated tin mud into the hydrochloric acid to carry out a leaching reaction at 105° C., and keep the temperature until the tin mud is completely dissolved, to obtain an acid leaching solution containing tin tetrachloride and ferric chloride.

[0091] S25. Configure a double-membrane electrolyzer, which includes an anode chamber, an intermediate chamber and a cathode chamber. A cation exchange membrane is provided between the anode chamber and the intermediate chamber for separation, and an anion exchange membrane is provided between the cathode chamber and the intermediate chamber for separation. A titanium plate or a graphite plate coated with a precious metal is provided in the anode chamber as a positive electrode, and a titanium plate or a copper plate is provided in the cathode chamber as a negative electrode.

[0092] S26, using acid leaching solution as the cathode reaction solution of the cathode chamber, using dilute sulfuric acid solution as the anode reaction solution of the anode chamber, and using dilute hydrochloric acid solution as the intermediate reaction solution of the intermediate chamber for double membrane electrolysis reaction, the mass concentration of dilute sulfuric acid in the anode chamber is 1.5wt%, and the mass concentration of dilute hydrochloric acid in the intermediate chamber is 0.5wt%. The cathode chamber electrode produces metallic tin with a purity of 99.13wt%, and the electrolytic residual solution is ferrous chloride solution, which is oxidized with the oxygen produced in the anode chamber to obtain ferric chloride solution, and the hydrochloric acid solution produced in the intermediate chamber is used as a raw material source for the heat preservation leaching reaction.

[0093] Example 3

[0094] A method for regenerating waste tin stripping water, as shown in FIG1 , comprises the following steps:

[0095] S31, volume is 10m 3 Add 8m3 of volume into the reactor3 The waste tin stripping water was started to stir, steam was introduced to raise the temperature to 120°C, 27.5wt% hydrogen peroxide 80L and 98wt% sulfuric acid 40L were added to the waste tin stripping water, the volume ratio of hydrogen peroxide, sulfuric acid and waste tin stripping water was 0.01:0.005:1, and the reaction was kept warm for 1h before solid-liquid separation to obtain tin precipitation mother liquor and tin mud. The dry basis tin content of the obtained tin mud was 61.37wt%, and the residual tin content in the tin precipitation mother liquor was 791mg / L.

[0096] S32. Add 99wt% oxalic acid (3 times the mass of total copper in the tin-stripping mother liquor) to the tin-stripping mother liquor, react for 2 hours, and then perform solid-liquid separation to obtain copper oxalate and tin-stripping sub-liquid. The residual copper content in the tin-stripping sub-liquid is 2.2g / L.

[0097] S33. Add water to the pulping kettle, wherein the amount of water added is 5 times the mass of the tin mud, stir at a speed of 50 Hz, add the tin mud for slurry washing for 4 hours, separate the solid and liquid to obtain the pretreated tin mud and the washing filtrate, and the washing filtrate enters the wastewater station system for treatment to recover the copper mud.

[0098] S34, add hydrochloric acid in an amount 1.5 times the stoichiometric amount required to completely dissolve the tin and iron in the pretreated tin mud into the dissolving kettle, start stirring, add the pretreated tin mud into the hydrochloric acid to carry out a leaching reaction at 105° C., and keep the temperature until the tin mud is completely dissolved, to obtain an acid leaching solution containing tin tetrachloride and ferric chloride.

[0099] S35. Configure a double-membrane electrolyzer, which includes an anode chamber, an intermediate chamber and a cathode chamber. A cation exchange membrane is provided between the anode chamber and the intermediate chamber for separation, and an anion exchange membrane is provided between the cathode chamber and the intermediate chamber for separation. A titanium plate or a graphite plate coated with a precious metal is provided in the anode chamber as a positive electrode, and a titanium plate or a copper plate is provided in the cathode chamber as a negative electrode.

[0100] S36, double membrane electrolysis reaction is carried out using acid leaching solution as cathode reaction solution of cathode chamber, dilute sulfuric acid solution as anode reaction solution of anode chamber, and dilute hydrochloric acid solution as intermediate reaction solution of intermediate chamber. The mass concentration of dilute sulfuric acid in anode chamber is 1wt%. The mass concentration of dilute hydrochloric acid in intermediate chamber is 0.2wt%. The cathode chamber electrode produces metallic tin with a purity of 98.32wt%. The residual electrolytic solution is ferrous chloride solution, which is oxidized with oxygen produced in anode chamber to obtain ferric chloride solution. The hydrochloric acid solution produced in intermediate chamber is used as a raw material source for heat preservation leaching reaction.

[0101] Example 4

[0102] A method for regenerating waste tin stripping water, as shown in FIG1 , comprises the following steps:

[0103] S41, to a volume of 10m 3Add 8m3 of volume into the reactor 3 The waste tin stripping water was started to stir, steam was introduced to raise the temperature to 120°C, 27.5wt% hydrogen peroxide 80L and 98wt% sulfuric acid 80L were added to the waste tin stripping water, the volume ratio of hydrogen peroxide, sulfuric acid and waste tin stripping water was 0.05:0.01:1, and the reaction was kept warm for 1h before solid-liquid separation to obtain tin precipitation mother liquor and tin mud. The dry basis tin content of the obtained tin mud was 61.45wt%, and the residual tin content in the tin precipitation mother liquor was 357mg / L.

[0104] S42. Add 99wt% oxalic acid in an amount of 2.5 times the total copper mass in the tin precipitation mother liquor to the tin precipitation mother liquor, react for 1 hour, and then perform solid-liquid separation to obtain copper oxalate and tin stripping liquid. The residual copper content in the tin stripping liquid is 3.2g / L.

[0105] S43. Add water to the pulping kettle, wherein the amount of water added is 3 times the mass of the tin mud, stir at a speed of 50 Hz, add the tin mud for slurry washing for 2 hours, separate the solid and liquid to obtain the pretreated tin mud and the washing filtrate, and the washing filtrate enters the wastewater station system for treatment to recover the copper mud.

[0106] S44, add hydrochloric acid in an amount 1.5 times the stoichiometric amount required to completely dissolve the tin and iron in the pretreated tin mud into the dissolving kettle, start stirring, add the pretreated tin mud into the hydrochloric acid to carry out a leaching reaction at 95°C until the tin mud is completely dissolved, and obtain an acid leaching solution containing tin tetrachloride and ferric chloride.

[0107] S45. Configure a double-membrane electrolyzer, which includes an anode chamber, an intermediate chamber and a cathode chamber. A cation exchange membrane is provided between the anode chamber and the intermediate chamber for separation, and an anion exchange membrane is provided between the cathode chamber and the intermediate chamber for separation. A titanium plate or a graphite plate coated with a precious metal is provided in the anode chamber as a positive electrode, and a titanium plate or a copper plate is provided in the cathode chamber as a negative electrode.

[0108] S46, double membrane electrolysis reaction is carried out using acid leaching solution as cathode reaction solution of cathode chamber, dilute sulfuric acid solution as anode reaction solution of anode chamber, and dilute hydrochloric acid solution as intermediate reaction solution of intermediate chamber. The mass concentration of dilute sulfuric acid in anode chamber is 2wt%. The mass concentration of dilute hydrochloric acid in intermediate chamber is 0.5wt%. The cathode chamber electrode produces metallic tin with a purity of 98.25wt%. The residual electrolytic solution is ferrous chloride solution, which is oxidized with oxygen produced in anode chamber to obtain ferric chloride solution. The hydrochloric acid solution produced in intermediate chamber is used as a raw material source for heat preservation leaching reaction.

[0109] Comparative Example 1

[0110] The waste tin stripping water regeneration treatment is carried out in the same manner as in Example 1, except that: in step S11, 4 kg of 99 wt% oxalic acid as a precipitation aid is added to the waste tin stripping water, and the mass volume ratio of the added amount of oxalic acid to the waste tin stripping water is 0.5 kg:1 m 3 The dry tin content of the obtained tin mud was 61.71wt%, the residual tin content in the tin precipitation mother liquor was 2.57g / L, the residual copper content in the tin stripping water was 4.6g / L, and the purity of the metallic tin produced by the cathode chamber electrode was 98.83wt%.

[0111] Comparative Example 2

[0112] The waste tin stripping water regeneration treatment is carried out in the same manner as in Example 1, except that: in step S11, 48 kg of 99 wt% oxalic acid as a precipitation aid is added to the waste tin stripping water, and the mass volume ratio of the added amount of oxalic acid to the waste tin stripping water is 6 kg:1 m 3 The dry tin content of the obtained tin mud was 56.37wt%, the residual tin content in the tin precipitation mother liquor was 222mg / L, the residual copper content in the tin stripping water was 3.6g / L, and the purity of the metallic tin produced by the cathode chamber electrode was 96.87wt%.

[0113] Comparative Example 3

[0114] The waste tin stripping water regeneration treatment was carried out in the same manner as in Example 1, with the main difference being that in step S12, 99wt% oxalic acid, which was twice the mass of the total copper in the tin stripping mother liquor, was added to the tin precipitate mother liquor for reaction for 1 hour, and then solid-liquid separation was performed to obtain copper oxalate and tin stripping water sub-liquid. The residual copper content in the tin stripping water sub-liquid was 5.5g / L.

[0115] Comparative Example 4

[0116] The waste tin stripping water regeneration treatment is carried out in the same manner as in Example 1, with the main difference being that in step S13, water is added to the pulping kettle, wherein the amount of water added is twice the mass of the tin mud. The purity of the metallic tin produced by the cathode chamber electrode is 96.46wt%.

[0117] By comparing Example 1 with Comparative Example 1, it can be seen that in Comparative Example 1, when tin is precipitated, the mass volume ratio of the added amount of oxalic acid to the waste tin stripping water is 0.5kg:1m 3 The amount of oxalic acid added is too small, resulting in part of the tin in the waste tin stripping water being unable to be recycled. The residual tin content in the tin precipitation mother liquor is as high as 2.57g / L, and the tin recovery rate is low.

[0118] By comparing Example 1 with Comparative Example 2, it can be seen that in Comparative Example 2, when tin is precipitated, the mass volume ratio of the added amount of oxalic acid to the waste tin stripping water is 6kg:1m 3If too much oxalic acid is added, the excess oxalic acid will react with the copper in the waste tin stripping water to generate a large amount of copper oxalate, which will co-precipitate with tin and affect the quality of the tin mud. The dry basis tin content in the tin mud of Comparative Example 2 is only 56.37wt%. It will also affect the subsequent deep treatment of the tin mud, resulting in the purity of the metallic tin in Comparative Example 2 being only 96.87wt%.

[0119] By comparing Example 1 with Comparative Example 3, it can be seen that in Comparative Example 3, when copper is deposited, the amount of 99wt% oxalic acid added is twice the total copper mass in the tin deposition mother liquor, and the amount of 99wt% oxalic acid added is too small, resulting in poor copper deposition effect. The residual copper content in the tin stripping water of Comparative Example 3 is as high as 5.5g / L, and the copper recovery rate is low.

[0120] By comparing Example 1 with Comparative Example 4, it can be seen that in Comparative Example 4, when the tin mud is slurried and washed, the amount of water added to the slurry kettle is twice the mass of the tin mud. The amount of water added is too little, resulting in poor washing effect of the tin mud. In the subsequent electrolysis step, the electrolysis efficiency and the purity of the metallic tin are affected, resulting in the purity of the metallic tin produced by the cathode chamber electrode being only 96.46wt%.

[0121] It can be seen from Examples 1 to 4 and Comparative Examples 1 to 4 that the dry basis tin content in the tin sludge obtained by the waste tin stripping water regeneration treatment method of the present application is more than 60wt%, and the metallic tin obtained after electrolytic treatment has a tin content of more than 98wt%, thereby realizing the effective separation and recovery of tin and copper in the waste tin stripping water.

[0122] In summary, compared with traditional technologies, the waste tin stripping water regeneration treatment method of the present application has the following technical effects.

[0123] (1) The effective separation and recovery of tin and copper in waste tin stripping water and the recycling and reuse of waste water are realized, thereby improving the level of resource utilization. α-stannic acid in waste tin stripping water is soluble in acid and alkali, while β-stannic acid is insoluble in nitric acid due to the stable structure of the colloid core. The present invention makes full use of the property of waste tin stripping water that can accelerate the conversion of α-stannic acid into β-stannic acid under heating conditions, and by adding a precipitation aid, the soluble α-stannic acid is converted into β-stannic acid precipitation, while promoting the aggregation and sedimentation of β-stannic acid to improve the filtration performance. Since the amount of precipitation aid added is small and the concentration is low, it preferentially reacts with α-stannic acid in a strong acid system and rarely reacts with copper ions for precipitation. The copper ions are mainly retained in the tin precipitation mother liquor, thereby achieving the effective separation of tin and copper in waste tin stripping water. The invention uses an acidic precipitant such as oxalic acid to precipitate and recover copper in a tin precipitation mother liquor to prepare an acid salt of copper such as copper oxalate. The acidic precipitant is used in a small amount and has a low cost. The acidic precipitant is suitable for use under strong acid conditions and will not damage the acid value in the system. The tin stripping water sub-liquid after the acidic salt of copper such as copper oxalate is recovered meets the requirements of the raw material of tin stripping water for printed circuit boards, can be reused in the tin stripping water preparation section, realizes regeneration and recycling, effectively reduces the amount of wastewater generated, and reduces the costs of waste-producing enterprises and waste treatment enterprises in a recycling mode.

[0124] (2) Realize the recycling of valuable resources in waste tin stripping water and obtain high-value resource products. The present invention utilizes waste tin stripping water as a resource. Through gradient recovery technology, product deep processing technology, and wastewater treatment technology that maximizes resources, high-value resource products such as tin mud, copper acid salts such as copper oxalate, tin stripping water sub-liquid, metallic tin, ferric chloride solution, and hydrochloric acid solution are successively obtained. Among them, the tin mud has a high grade and its dry basis tin content is more than 60wt%. The metallic tin obtained after electrolytic treatment has a tin content of more than 98wt%. The ferric chloride solution is used as a water purifier in the wastewater station, and the hydrochloric acid solution is reused in the tin mud leaching section, realizing the maximum recycling of valuable resources in the waste tin stripping water.

[0125] (3) The present application can realize the high-value comprehensive utilization of valuable resources in waste tin stripping water and effectively reduce the cost of waste tin stripping water treatment. The waste tin stripping water regeneration treatment method of the present application can recycle the waste tin stripping water generated in the printed circuit board manufacturing process in a high-value manner.

[0126] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0127] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0128] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for regenerating waste tin stripping water, characterized in that: The steps include: Adding waste tin stripping water into a reactor, stirring and controlling the temperature, adding a precipitation aid to the waste tin stripping water, reacting, and then separating the solid and liquid to obtain a tin precipitation mother liquor and tin mud; Adding an acidic precipitant to the tin precipitation mother liquor to react and then separating the solid and liquid to obtain an acid salt of copper and a tin stripping liquid; The tin mud is subjected to slurry washing treatment and then solid-liquid separation to obtain pre-treated tin mud and washing filtrate; Adding hydrochloric acid to a dissolving kettle and stirring, adding pretreated tin mud to the hydrochloric acid to carry out heat preservation leaching reaction until the tin mud is completely dissolved to obtain an acid leaching solution containing at least tin tetrachloride and ferric chloride; The acid leaching solution is used as the cathode reaction solution of the cathode chamber, the dilute sulfuric acid solution is used as the anode reaction solution of the anode chamber, and the dilute hydrochloric acid solution is used as the intermediate reaction solution of the intermediate chamber to carry out a double-membrane electrolysis reaction, thereby obtaining a metallic tin and ferrous chloride solution located in the cathode chamber, a hydrochloric acid solution located in the intermediate chamber, and oxygen generated in the anode chamber.

2. The method for regenerating waste tin stripping water according to claim 1, characterized in that: When adding the waste tin stripping water into the reactor and stirring and controlling the temperature, the following steps are included: The waste tin stripping water is heated by one or more methods including coil, jacket and steam, and the temperature is controlled to 85℃~120℃.

3. The method for regenerating waste tin stripping water according to claim 1, characterized in that: The precipitation aid includes oxalic acid, and the precipitation aid is added to the waste tin stripping water for reaction, and then solid-liquid separation is performed to obtain a tin precipitation mother liquor and tin mud, which includes the following steps: adding oxalic acid to the waste tin stripping water, and then heat-preserving the reaction for 1h~2h, and then solid-liquid separation is performed to obtain a tin precipitation mother liquor and tin mud, wherein the mass volume ratio of the added amount of the oxalic acid to the waste tin stripping water is (1kg~5kg): 1m 3 .

4. The method for regenerating waste tin stripping water according to claim 1, characterized in that: The precipitation aid comprises hydrogen peroxide and sulfuric acid. When the precipitation aid is added to the waste tin stripping water for reaction and then solid-liquid separation is performed to obtain a tin precipitation mother liquor and tin mud, the method comprises the following steps: adding 27.5wt% hydrogen peroxide and 98wt% sulfuric acid to the waste tin stripping water, preserving the reaction for 2h~4h, and then solid-liquid separation is performed to obtain a tin precipitation mother liquor and tin mud, wherein the volume ratio of the hydrogen peroxide, the sulfuric acid, and the waste tin stripping water is (0.01~0.05):(0.005~0.01):

1.

5. The method for regenerating waste tin stripping water according to any one of claims 1 to 4, characterized in that: The waste tin stripping water regeneration treatment method meets at least one of the following conditions: (1) When an acidic precipitant is added to the tin precipitation mother solution, the amount of the acidic precipitant added is 2.5 to 3 times the total copper mass in the tin precipitation mother solution; (2) The reaction time of adding an acidic precipitant to the tin precipitation mother solution is 1 h to 2 h; (3) The acidic precipitant includes 99 wt % oxalic acid, and the acidic salt of copper obtained is copper oxalate; (4) The tin stripping water sub-liquid can be used to regenerate tin stripping water.

6. The method for regenerating waste tin stripping water according to any one of claims 1 to 4, characterized in that: The waste tin stripping water regeneration treatment method meets at least one of the following conditions: (1) when adding the pretreated tin mud to the hydrochloric acid for heat preservation leaching reaction, the amount of hydrochloric acid added is 1 to 1.5 times the stoichiometric amount required for complete dissolution of tin and iron in the pretreated tin mud; (2) The temperature during the heat preservation leaching reaction is 95℃~105℃.

7. The method for regenerating waste tin stripping water according to any one of claims 1 to 4, characterized in that: A double-membrane electrolytic cell is used for double-membrane electrolysis reaction, and the double-membrane electrolytic cell includes an anode chamber, an intermediate chamber and a cathode chamber. A cation exchange membrane is provided between the anode chamber and the intermediate chamber for separation, and an anion exchange membrane is provided between the cathode chamber and the intermediate chamber for separation. A titanium plate or a graphite plate coated with a precious metal is provided in the anode chamber as a positive electrode, and a titanium plate or a copper plate is provided in the cathode chamber as a negative electrode.

8. The method for regenerating waste tin stripping water according to claim 7, characterized in that: The waste tin stripping water regeneration treatment method meets at least one of the following conditions: (1) The mass concentration of dilute sulfuric acid in the anode chamber is 1wt%~2wt%; (2) The mass concentration of the dilute hydrochloric acid in the intermediate chamber is 0.2wt%~0.5wt%.

9. The method for regenerating waste tin stripping water according to any one of claims 1 to 4, characterized in that: When the tin mud is subjected to slurry washing treatment, the following steps are included: Add water to the pulping kettle, wherein the amount of water added is 3 to 5 times the mass of the tin mud, stir at a speed of 40 Hz to 50 Hz, add tin mud for slurry washing for 2 h to 4 h, and then separate the solid and liquid to obtain the pretreated tin mud and washing filtrate.

10. The method for regenerating waste tin stripping water according to any one of claims 1 to 4, characterized in that: The waste tin stripping water regeneration treatment method meets at least one of the following conditions: (1) The washing filtrate enters the wastewater station system for treatment to recover copper mud; (2) The hydrochloric acid solution obtained in the intermediate chamber is used as a raw material source for the heat preservation leaching reaction; (3) The oxygen generated in the anode chamber is used to oxidize the ferrous chloride solution generated in the cathode chamber to obtain a ferric chloride solution.

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