Deplating solution and green recycling method for extracting copper, tin and lead from retired photovoltaic welding strip

Abstract

The invention discloses a deplating solution and a green recycling method for extracting copper, tin and lead from a retired photovoltaic welding strip. The deplating solution comprises a leaching solution and a micro-nano bubble stabilizer, wherein the leaching solution comprises an organic acid solution, an acidic copper salt and an acidic trivalent iron salt. The stripping solution is rich in raw material source, green and safe, meanwhile, copper, tin and lead are recycled from the retired photovoltaic welding strip through the stripping solution, the recycling efficiency is high, the recycling cost is low, and economic benefits are good.

Description

Technical Field

[0001] This invention belongs to the field of recycling technology for decommissioned photovoltaic modules. Specifically, this invention relates to a stripping solution and a green recycling method for extracting copper, tin, and lead from decommissioned photovoltaic solder strips. Background Technology

[0002] Photovoltaic power generation has become the mainstay of my country's new energy power generation technology. The large-scale use of photovoltaic products has led to a massive amount of retired and discarded photovoltaic modules. The lifespan of photovoltaic modules is between 20 and 25 years. Currently, the first generation of photovoltaic modules in China has entered its end-of-life period. It is predicted that this will reach 1.05 million tons and 10 million tons in 2025 and 2030 respectively, making it the world's fastest-growing source of electronic waste. If these discarded modules are not disposed of properly, harmful heavy metals such as lead, copper, and tin solder may seep into the soil and water, causing environmental pollution. At the same time, the high-value metal components are important renewable resources; improper disposal will also lead to resource waste.

[0003] Photovoltaic solder ribbon, also known as tin-plated copper ribbon or tin-coated copper ribbon, is an important component of photovoltaic modules (such as...). Figure 1 As shown), it consists of a copper substrate and a tin-lead alloy (Sn60 / Pb40) surface coating, and has high recycling value. The traditional tin stripping process is mainly the etching of tin plating on PCB circuit boards. It mainly uses a nitric acid system composed of high-concentration nitric acid and ferric nitrate for tin stripping. The concentration of nitric acid is generally 20-25%. This type of stripping agent has a complex composition and is troublesome to prepare. Moreover, the decomposition of nitric acid during tin stripping will produce a large amount of nitrogen oxide gas, which will cause serious environmental pollution. Another method is to use sulfuric acid-hydrogen peroxide process for tin stripping. Although this type of tin stripping process does not use the heavily polluting nitric acid, the tin stripping speed is slow and the production efficiency is low. In addition, due to the catalytic decomposition of metal ions and the exothermic reaction of metal dissolution, the hydrogen peroxide decomposes very quickly and is consumed in large quantities. It can only treat thin pure tin plating layers and is not effective for tin-lead alloy plating layers.

[0004] Chinese invention patent (CN117385163A) uses acid pickling and detinning solution to remove tin plating from waste circuit boards. This acid pickling and detinning solution uses high-concentration sulfuric acid and fluoroboric acid as the main agents, and adds copper nitrate, copper sulfate and cuprous chloride as detinning aids. The fluoroboric acid contained therein is highly toxic, which is very harmful to operators, causes great environmental pollution, and is difficult to treat. It is a chemical strictly controlled by the state.

[0005] Chinese invention patent (CN110760922A) uses an electrolyte solution containing nitric acid, sulfuric acid, methanesulfonic acid, and aminosulfonic acid to electrolyze and remove the tin plating layer on the substrate. During electrolysis, the nitric acid is reduced to NO2, NO, and NO3-. XNitrogen oxides are produced, generating large amounts of toxic and harmful gases, as well as electrolytic wastewater containing ammonia nitrogen, which poses a significant threat to the environment.

[0006] Chinese invention patent (CN110684904A) provides a method for recovering copper and tin from waste tin-plated copper wire. The method involves immersing the waste tin-plated copper wire in a low-concentration solution of copper sulfate or copper chloride and hydrochloric acid to leach out the tin, resulting in coarse copper wire and a stripping solution containing sediment. After separation, metallic copper wire and tin dioxide powder are obtained. The drawback of this method, which uses a low-concentration solution of copper sulfate or copper chloride and hydrochloric acid for stripping, is that the tin dissolved by the displacement reaction between metallic tin and soluble copper salts is only a very thin portion of the surface tin plating. The resulting metallic copper coats the surface of the tin plating, causing the displacement reaction to terminate. In practice, the tin plating layer of a certain thickness cannot be completely removed, leading to incomplete separation of tin and copper. The low concentration of copper salts also results in low actual stripping efficiency. Furthermore, the method does not explain in detail how to completely precipitate tin ions in the stripping solution. Additionally, the poor solubility of lead sulfate and lead chloride makes this process difficult to remove tin-lead alloy plating.

[0007] Therefore, it is necessary to develop a high-efficiency, environmentally friendly recycling process for decommissioned photovoltaic welding strips that separates and extracts copper, tin, and lead, in order to overcome the shortcomings of existing processes and improve the recycling efficiency of metal resources. Summary of the Invention

[0008] The present invention aims to at least partially solve one of the technical problems in the related art.

[0009] Therefore, embodiments of the present invention propose a stripping solution and a green recycling method for extracting copper, tin, and lead from decommissioned photovoltaic solder ribbons.

[0010] To achieve the above-mentioned objectives, the present invention adopts the following technical solution: In a first aspect, embodiments of the present invention provide a stripping solution for extracting copper, tin, and lead from decommissioned photovoltaic solder strips. The stripping solution includes an extraction solution and a micro / nano bubble stabilizer. The extraction solution includes an organic acid solution, an acidic copper salt, and an acidic ferric salt.

[0011] In some embodiments, the organic acid solution includes at least one of methanesulfonic acid solution, aminosulfonic acid solution, and acetic acid solution; Optionally, in the stripping solution, the mass concentration of the organic acid solution is 20~100g / L.

[0012] In some embodiments, the acidic copper salt includes at least one of copper acetate, copper methanesulfonate, and copper aminosulfonate; Optionally, the mass concentration of the acidic copper salt in the stripping solution is 15~150 g / L.

[0013] In some embodiments, the acidic ferric salt includes at least one of ferric sulfate, ferric citrate, ferric ammonium sulfate, and ferric chloride; Optionally, in the stripping solution, the mass concentration of the acidic trivalent iron salt is 20~200 g / L.

[0014] In some embodiments, the micro / nano bubble stabilizer includes at least one of octadecyltrimethylammonium chloride, hexadecyltrimethylammonium bromide, and sodium dodecyl sulfate; Optionally, the mass concentration of the micro / nano bubble stabilizer in the stripping solution is 0.5~1g / L.

[0015] Secondly, embodiments of the present invention also propose a green recycling method for extracting copper, tin, and lead from decommissioned photovoltaic solder ribbons using the stripping solution described in the first aspect, comprising the following steps: (1) The retired photovoltaic modules are pyrolyzed, physically crushed, sorted and cleaned to obtain photovoltaic welding strips; (2) The photovoltaic solder ribbon is immersed in a leaching solution for detinning and lead removal to obtain copper wire and detinning and lead removal solution, and the copper wire is cleaned to obtain clean copper wire; the leaching solution is the leaching solution described in the first aspect; (3) Add sulfuric acid to the lead-free solution obtained in step (2) to generate lead sulfate precipitate, and then separate the solid and liquid to obtain lead sulfate precipitate and tin-containing solution; (4) Adjust the pH of the tin-containing solution obtained in step (3) to 3-4, add a micro / nano bubble stabilizer to the tin-containing solution, and heat it. Then inject micro / nano bubbles into the tin-containing solution to reduce the Sn concentration in the tin-containing solution. 2+ Catalytic oxidation to Sn 4+ After hydrolysis and filtration, Sn(OH)4 precipitate and filtrate are obtained. The precipitate is then dried to obtain SnO2 powder. (5) Add organic acid to the filtrate obtained in step (4) and inject micro-nano bubbles to remove Fe from the filtrate. 2+ Catalytic oxidation to Fe 3+ This process regenerates ferric iron, and finally, the acidity of the filtrate is adjusted so that it can be recycled for preparing the leachate.

[0016] In some embodiments, in step (1), the content of the tin-lead solderability coating on the surface of the photovoltaic ribbon is 3wt% to 5wt%, the tin-lead alloy composition is Sn60 / Pb40, and the tin-lead coating thickness is 2 to 5 μm.

[0017] In some embodiments, in step (2), the soaking temperature is room temperature and the soaking time is 20-30 minutes.

[0018] In some embodiments, in step (4), the temperature of the heat treatment is 50~90°C; And / or, the Sn 2+ Catalytic oxidation to Sn 4+ The time is 10~60 minutes.

[0019] In some embodiments, in step (5), the Fe 2+ Catalytic oxidation to Fe 3+ The time is 10~30 minutes.

[0020] The advantages and beneficial effects of the embodiments of the present invention are as follows: (1) The method for recovering copper, tin, and lead from decommissioned photovoltaic welding strips in this embodiment of the invention does not require the use of reagents such as nitric acid and fluorosilicic acid, which are harmful to the environment and human body. Instead, it selects environmentally friendly organic acids as the base liquid and utilizes the unique physicochemical properties of micro-nano bubbles in solution, such as high specific surface area, long suspension residence time, generation of highly active oxidative free radicals, and enhanced gas dissolution and mass transfer, to rapidly and efficiently catalyze the oxidation of Sn in the solution. 2+ and Fe 2+ It replaces organic oxides such as peroxides and anti-staining salts, enabling the recycling of stripping solutions and making the recovery process safer and more environmentally friendly.

[0021] (2) The stripping solution used in the recovery method for extracting copper, tin, and lead from decommissioned photovoltaic solder ribbons in this embodiment of the invention is easy to prepare and has abundant raw material sources. In the recovery process, copper salt only needs to be added during the first recovery process. In subsequent processes, the copper metal replaced by metallic tin and lead can be recycled and oxidized into copper ions. And the Fe in the solution can be removed by micro-nano bubbles. 2+ Catalytic oxidation to Fe 3+ This restores the oxidizing properties of the solution, allowing it to be recycled for preparing stripping solutions, saving on recycling costs and avoiding wastewater discharge.

[0022] (3) The recycling method for extracting copper, tin and lead from retired photovoltaic welding strips in the embodiments of the present invention has high processing efficiency, low recycling cost and good economic benefits; and the recycling process achieves zero wastewater discharge, which is more green and environmentally friendly; at the same time, its recycling process is simple, easy to operate and easy to realize industrial promotion and application. Attached Figure Description

[0023] Figure 1 A schematic diagram showing the structure of tin-plated photovoltaic solder ribbon forming interconnect and busbar bands on a photovoltaic module.

[0024] Figure 2This is a process flow diagram of a green recycling method for extracting copper, tin, and lead from decommissioned photovoltaic solder ribbons according to an embodiment of the present invention. Detailed Implementation

[0025] The embodiments of the present invention are described in detail below. These embodiments are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0026] In this invention, when a value is described as a range, it should be understood that such disclosure includes disclosure of all possible subranges within that range, as well as specific numerical values ​​falling within that range, regardless of whether specific numerical values ​​or specific subranges are explicitly specified.

[0027] In this invention, the terms “comprising” and “including” and their various variations mean that other elements or wholes may be included but are not specifically described.

[0028] In this invention, the term "and / or" is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone.

[0029] In a first aspect, embodiments of the present invention provide a stripping solution for extracting copper, tin, and lead from decommissioned photovoltaic solder strips. The stripping solution includes an extraction solution and a micro / nano bubble stabilizer. The extraction solution includes an organic acid solution, an acidic copper salt, and an acidic ferric salt.

[0030] In some embodiments, the organic acid solution includes at least one of methanesulfonic acid solution, aminosulfonic acid solution, and acetic acid solution; Optionally, in the stripping solution, the mass concentration of the organic acid solution is 20~100g / L.

[0031] By selecting the above-mentioned organic acids, which are green and environmentally friendly and conducive to recycling, and will not form insoluble or sparingly soluble lead salts that affect the stripping effect; in addition, the inventors have also found through research that if the concentration of the organic acid solution is too high, it will lead to excessive acidity of the solution and serious carry-over losses; but if the concentration of the organic acid solution is too low, the reaction rate will be slow. Therefore, it is appropriate to control the concentration of the organic acid solution within the above-mentioned range in the embodiments of the present invention.

[0032] In some embodiments, the acidic copper salt includes at least one of copper acetate, copper methanesulfonate, and copper aminosulfonate; Optionally, the mass concentration of the acidic copper salt in the stripping solution is 15~150 g / L.

[0033] By selecting the above-mentioned acidic copper salt, it can form a soluble tin-lead solution with high solubility with tin and lead, which is beneficial for the rapid removal of tin-lead plating. Furthermore, the inventors have found through research that if the mass concentration of the acidic copper salt is too high, it will cause precipitation in the solution; however, if its mass concentration is too low, it will lead to incomplete reaction. Therefore, it is appropriate to control the mass concentration of the acidic copper salt in the range of 15~150g / L in the embodiments of the present invention.

[0034] In some embodiments, the acidic ferric salt includes at least one of ferric sulfate, ferric citrate, ferric ammonium sulfate, and ferric chloride; Optionally, in the stripping solution, the mass concentration of the acidic trivalent iron salt is 20~200 g / L.

[0035] By selecting the aforementioned acidic ferric salt, which has oxidizing properties, it is beneficial to dissolve the copper layer formed by the tin-lead displacement reaction. Furthermore, the inventors have found through research that if the mass concentration of the acidic ferric salt is too high, it will cause damage to the copper substrate; however, if the mass concentration of the acidic ferric salt is too low, it will slow down the reaction rate and affect the stripping effect. Therefore, it is appropriate to control the mass concentration of the acidic ferric salt within the above-mentioned range in the embodiments of the present invention.

[0036] In some embodiments, the micro / nano bubble stabilizer includes at least one of octadecyltrimethylammonium chloride, hexadecyltrimethylammonium bromide, and sodium dodecyl sulfate; Optionally, the mass concentration of the micro / nano bubble stabilizer in the stripping solution is 0.5~1g / L.

[0037] By introducing micro- and nano-bubble stabilizers, the surface tension of aqueous solutions can be reduced, thereby improving the stability of micro- and nano-bubbles. Furthermore, the inventors have found that if the mass concentration of the micro- and nano-bubble stabilizer is too low, the generation efficiency of micro- and nano-bubbles will be low and the energy consumption will be high. However, if the mass concentration of the micro- and nano-bubble stabilizer is too high, especially if it exceeds the critical micelle concentration, a large number of macro-bubbles will be formed, which will hinder gas mass transfer and free radical generation. Therefore, it is advantageous to control the mass concentration of the micro- and nano-bubble stabilizer in the range of 0.5 to 1 g / L in the embodiments of the present invention.

[0038] In some embodiments, the leaching solution is prepared by a method comprising the following steps: dissolving an organic acid in water to obtain an organic acid solution; then adding an acidic copper salt to the organic acid solution and stirring to mix; subsequently adding an acidic ferric salt to the mixture and stirring to mix, thereby obtaining the leaching solution.

[0039] It should be noted that the aforementioned micro-nano bubble stabilizer is added during the regeneration process.

[0040] Secondly, such as Figure 2 As shown, this embodiment of the invention also proposes a green recycling method for extracting copper, tin, and lead from decommissioned photovoltaic solder ribbons using the stripping solution described in the first aspect, comprising the following steps: (1) The retired photovoltaic modules are pyrolyzed, physically crushed, sorted and cleaned to obtain photovoltaic welding strips; (2) The photovoltaic solder ribbon is immersed in a leaching solution for detinning (as shown in reaction formulas (1), (2), and (3)) to obtain copper wire and detinning solution, and the copper wire is cleaned to obtain clean copper wire; the leaching solution is the leaching solution described in the first aspect; (3) Add sulfuric acid to the lead-free solution obtained in step (2) to generate lead sulfate precipitate (as shown in reaction formula (4)), and then separate the solid and liquid to obtain lead sulfate precipitate and tin-containing solution; (4) Adjust the pH of the tin-containing solution obtained in step (3) to 3-4, add a micro / nano bubble stabilizer to the tin-containing solution, and heat it. Then inject micro / nano bubbles into the tin-containing solution to reduce the Sn concentration in the tin-containing solution. 2+ Catalytic oxidation to Sn 4+ After hydrolysis and filtration, Sn(OH)4 precipitate and filtrate are obtained. The precipitate is then dried to obtain SnO2 powder (as shown in reaction formulas (5), (6), and (7)). (5) Add organic acid to the filtrate obtained in step (4) and inject micro-nano bubbles to remove Fe from the filtrate. 2+ Catalytic oxidation to Fe 3+ (As shown in reaction formula (8)), the regeneration of ferric iron is achieved, and finally the acidity of the filtrate is adjusted so that it can be recycled for the preparation of the leachate.

[0041] The idea and principle of this invention are as follows: This invention utilizes the potential difference between metallic tin, lead, and copper. An acidic copper salt solution is used to dissolve and remove the tin-lead plating on decommissioned photovoltaic solder ribbons. To address the issue of copper encapsulating the tin-lead plating during the replacement process, which terminates the Sn-Cu replacement reaction and results in incomplete removal of the tin-lead plating (only partial dissolution), an acidic ferric ion solution is used to dissolve the copper surrounding the tin-lead plating, allowing the Sn-Cu replacement reaction to continue. This process involves replacement-copper dissolution (replacing the copper layer)-re-replacement-re-copper dissolution (replacing the copper layer) until the tin-lead plating on the copper substrate is completely dissolved and removed. The copper substrate and the tin-lead removal solution are then separated into solid and liquid components to obtain copper wire and the tin-lead removal solution. The tin-lead removal solution reacts with sulfuric acid to obtain lead sulfate precipitate and a tin-containing solution. The pH of the tin-containing solution is adjusted, and micro / nano bubbles are used to catalyze the oxidation of Sn in the tin-containing solution. 2+ For Sn 4+This process yields Sn(OH)4 precipitate and filtrate; then, organic acids and micro / nano bubbles are used to remove Fe from the filtrate. 2+ Catalytic oxidation to Fe 3+ This allows the filtrate to be regenerated and recycled.

[0042] The reactions involved in the green recycling method for extracting copper, tin, and lead from decommissioned photovoltaic solder ribbons according to embodiments of the present invention are as follows: Sn+Cu 2+ =Sn 2+ +Cu↓(1) Pb+Cu 2+ =Pb 2+ +Cu↓ (2) Cu + 2Fe 3+ =2Fe 2+ +Cu 2+ (3) Pb 2+ +SO4 2- =PbSO4↓(4) 2Sn 2+ +4H + +O2=2Sn 4+ +2H2O (5) Sn 4+ +4H₂O=4H + +Sn(OH)4↓(6) Sn(OH)4 = SnO2↓ + H2O (7) 4Fe 2+ +4H + +O2=4Fe 3+ +2H2O (8) In some embodiments, in step (1), the content of the tin-lead solderability coating on the surface of the photovoltaic ribbon is 3wt% to 5wt%, the tin-lead alloy composition is Sn60 / Pb40, and the tin-lead coating thickness is 2 to 5 μm.

[0043] It should also be noted that in step (1), the retired photovoltaic modules are subjected to a series of pretreatment processes (such as pyrolysis, physical crushing, sorting, cleaning, etc.) to obtain photovoltaic welding strips. This process is a conventional operation in the field and will not be described in detail here.

[0044] In some embodiments, in step (2), the soaking temperature is room temperature and the soaking time is 20-30 minutes.

[0045] In some embodiments, in step (3), the Pb in the lead stripping solution 2+ With the SO4 in the sulfuric acid 2- The molar ratio is 1:(1~1.2) to ensure the Pb concentration in the lead stripping solution.2+ It can precipitate as completely as possible, forming PbSO4 precipitate.

[0046] In some embodiments, in step (4), the temperature of the heat treatment is 50~90°C; And / or, the Sn 2+ Catalytic oxidation to Sn 4+ The time is 10~60 minutes.

[0047] In some embodiments, in step (5), the Fe 2+ Catalytic oxidation to Fe 3+ The time is 10~30 minutes.

[0048] It should also be noted that the micro-nano bubbles in steps (4) and (5) above are generated by a micro-nano bubble generator, and the gas medium in the micro-nano bubble generator is air or oxygen. By using a micro-nano bubble generator to generate micro-nano bubbles, the micro-nano bubbles can release hydroxyl radicals (·OH) when they burst, and have strong oxidizing ability, which can oxidize low-valence metal ions in the solution into high-valence metal ions.

[0049] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. Unless otherwise stated, all raw materials used in the embodiments are conventional commercially available products, or can be prepared by known methods; and the experimental methods not specified in the embodiments are conventional methods and conditions well known in the art.

[0050] Example 1 This embodiment provides a green recycling method for extracting copper, tin, and lead from decommissioned photovoltaic solder ribbons, including the following steps: (1) The retired photovoltaic modules are pyrolyzed, physically crushed, sorted and cleaned to obtain photovoltaic welding strips; (2) Take 1000g of photovoltaic solder ribbon (of which the content of tin-lead Sn60 / Pb40 solderable coating is about 3wt%, that is, the mass of tin-lead Sn60 / Pb40 solderable coating to be removed is about 30g) and immerse it in 5L of leaching solution for detin-lead treatment. After immersion at room temperature for 30min, copper wire with tin-lead coating removed and detin-lead solution are obtained. The copper wire is then washed with water to obtain clean copper wire. The leaching solution is prepared by acetic acid, copper acetate and ferric sulfate, and the concentration of acetic acid is 15g / L, the concentration of copper acetate is 10g / L and the concentration of ferric sulfate is 60g / L. (3) The concentration of lead ions in the lead stripping solution obtained in step (2) was detected by ICP (inductively coupled plasma spectroscopy), and then the concentration of Pb in the lead stripping solution was determined according to the Pb concentration in the lead stripping solution. 2+ With SO4 in sulfuric acid 2-The molar ratio is 1:1. Sulfuric acid (98%) is added to the lead-tin stripping solution and stirred for 10 minutes to generate lead sulfate precipitate. After standing and filtration, lead sulfate precipitate and tin-containing solution are obtained. (4) Adjust the pH of the tin-containing solution obtained in step (3) to 3-4, add octadecyltrimethylammonium chloride (concentration of 1 g / L) to the tin-containing solution, heat the tin-containing solution to 70°C, then turn on the micro-nano bubble generator (using air as the gas medium), adjust the air flow rate to 6 L / min, and inject micro-nano bubbles into the tin-containing solution. After 30 min, the Sn in the tin-containing solution... 2+ Complete catalytic oxidation to Sn 4+ After hydrolysis and filtration, Sn(OH)4 precipitate and filtrate are obtained. The Sn(OH)4 precipitate is then dried to obtain SnO2 powder, which is then recycled. (5) Then add 30g of acetic acid to the filtrate obtained in step (4), and turn on the micro-nano bubble generator again (using air as the gas medium), adjust the air flow rate to 10L / min, and inject micro-nano bubbles into the filtrate to remove Fe from the filtrate. 2+ Catalytic oxidation to Fe 3+ The ferric iron was regenerated by catalytic oxidation at room temperature for 30 minutes. Finally, the acidity of the filtrate was adjusted to its initial state by using acetic acid and the water produced in each process to make it recyclable for preparing the leachate.

[0051] In this embodiment, the recovery rates are 99% for copper, 98% for tin, and 98% for lead.

[0052] Example 2 This embodiment provides a green recycling method for extracting copper, tin, and lead from decommissioned photovoltaic solder ribbons, including the following steps: (1) The retired photovoltaic modules are pyrolyzed, physically crushed, sorted and cleaned to obtain photovoltaic welding strips; (2) Take 1000g of photovoltaic solder ribbon (of which the content of tin-lead Sn60 / Pb40 solderable coating is about 3wt%, that is, the mass of tin-lead Sn60 / Pb40 solderable coating to be removed is about 30g) and immerse it in 5L of leaching solution for detin-lead treatment. After immersion at room temperature for 30min, copper wire with tin-lead coating removed and detin-lead solution are obtained. The copper wire is then washed with water to obtain clean copper wire. The leaching solution is prepared by methanesulfonic acid, copper methanesulfonate and ferric chloride, and the concentration of methanesulfonic acid is 20g / L, the concentration of copper methanesulfonate is 15g / L and the concentration of ferric chloride is 60g / L. (3) The concentration of lead ions in the lead stripping solution obtained in step (2) was detected by ICP (inductively coupled plasma spectroscopy), and then the concentration of Pb in the lead stripping solution was determined according to the Pb concentration in the lead stripping solution. 2+ With SO4 in sulfuric acid2- The molar ratio is 1:1.05. Sulfuric acid (98%) is added to the lead-tin stripping solution and stirred for 10 minutes to generate lead sulfate precipitate. After standing and filtration, lead sulfate precipitate and tin-containing solution are obtained. (4) Adjust the pH of the tin-containing solution obtained in step (3) to 3-4, and add hexadecyltrimethylammonium bromide (concentration of 0.5 g / L) to the tin-containing solution. Heat the tin-containing solution to 80°C, and then turn on the micro-nano bubble generator (using air as the gas medium), adjust the air flow rate to 5 L / min, and inject micro-nano bubbles into the tin-containing solution. After 40 min, the Sn in the tin-containing solution... 2+ Complete catalytic oxidation to Sn 4+ After hydrolysis and filtration, Sn(OH)4 precipitate and filtrate are obtained. The Sn(OH)4 precipitate is then dried to obtain SnO2 powder, which is then recycled. (5) Then add 40g of methanesulfonic acid to the filtrate obtained in step (4), and turn on the micro-nano bubble generator again (using air as the gas medium), adjust the air flow rate to 10L / min, and inject micro-nano bubbles into the filtrate to remove Fe from the filtrate. 2+ Catalytic oxidation to Fe 3+ Catalytic oxidation at 60℃ for 10 minutes regenerated ferric iron. Finally, acetic acid and water from each process were used to wash the filtrate to adjust its acidity to the initial state, allowing it to be recycled for preparing the leachate.

[0053] In this embodiment, the recovery rates are 98.5% for copper, 98% for tin, and 98% for lead.

[0054] Example 3 This embodiment provides a green recycling method for extracting copper, tin, and lead from decommissioned photovoltaic solder ribbons, including the following steps: (1) The retired photovoltaic modules are pyrolyzed, physically crushed, sorted and cleaned to obtain photovoltaic welding strips; (2) Take 1000g of photovoltaic solder ribbon (of which the content of tin-lead Sn60 / Pb40 solderable coating is about 3wt%, that is, the mass of tin-lead Sn60 / Pb40 solderable coating to be removed is about 30g) and immerse it in 5L of leaching solution for detin-lead treatment. After immersion at room temperature for 30min, copper wire with tin-lead coating removed and detin-lead solution are obtained. The copper wire is then washed with water to obtain clean copper wire. The leaching solution is prepared from aminosulfonic acid, copper aminosulfonate and ferric ammonium sulfate, and the concentration of aminosulfonic acid is 20g / L, the concentration of copper aminosulfonate is 15g / L and the concentration of ferric ammonium sulfate is 65g / L. (3) The concentration of lead ions in the lead stripping solution obtained in step (2) was detected by ICP (inductively coupled plasma spectroscopy), and then the concentration of Pb in the lead stripping solution was determined according to the Pb concentration in the lead stripping solution.2+ With SO4 in sulfuric acid 2- The molar ratio is 1:1.1. Sulfuric acid (98%) is added to the lead-tin stripping solution and stirred for 10 minutes to generate lead sulfate precipitate. After standing and filtration, lead sulfate precipitate and tin-containing solution are obtained. (4) Adjust the pH of the tin-containing solution obtained in step (3) to 3-4, add hexadecyltrimethylammonium chloride (1 g / L) to the tin-containing solution, heat the tin-containing solution to 50°C, then turn on the micro / nano bubble generator (using air as the gas medium), adjust the air flow rate to 5 L / min, and inject micro / nano bubbles into the tin-containing solution. After 50 min, the Sn in the tin-containing solution... 2+ Complete catalytic oxidation to Sn 4+ After hydrolysis and filtration, Sn(OH)4 precipitate and filtrate are obtained. The Sn(OH)4 precipitate is then dried to obtain SnO2 powder, which is then recycled. (5) Then add 40g of aminosulfonic acid to the filtrate obtained in step (4), and turn on the micro-nano bubble generator again (using air as the gas medium), adjust the air flow rate to 8L / min, and inject micro-nano bubbles into the filtrate to remove Fe from the filtrate. 2+ Catalytic oxidation to Fe 3+ Catalytic oxidation at 40℃ for 30 minutes regenerated ferric iron. Finally, aminosulfonic acid and water generated from each process were used to adjust the acidity of the filtrate to its initial state, so that it could be recycled for preparing the leachate.

[0055] In this embodiment, the recovery rates were 98.5% for copper, 97.3% for tin, and 98% for lead.

[0056] Example 4 This embodiment provides a green recycling method for extracting copper, tin, and lead from decommissioned photovoltaic solder ribbons, including the following steps: (1) The retired photovoltaic modules are pyrolyzed, physically crushed, sorted and cleaned to obtain photovoltaic welding strips; (2) Take 1000g of photovoltaic solder ribbon (of which the content of tin-lead Sn60 / Pb40 solderable coating is about 3wt%, that is, the mass of tin-lead Sn60 / Pb40 solderable coating to be removed is about 30g) and immerse it in 4L of leaching solution for detin-lead treatment. After immersion at room temperature for 30min, copper wire with tin-lead coating removed and detin-lead solution are obtained. The copper wire is then washed with water to obtain clean copper wire. The leaching solution is prepared by methanesulfonic acid, copper methanesulfonate and ferric chloride, and the concentration of methanesulfonic acid is 30g / L, the concentration of copper methanesulfonate is 25g / L and the concentration of ferric chloride is 60g / L. (3) The concentration of lead ions in the lead stripping solution obtained in step (2) was detected by ICP (inductively coupled plasma spectroscopy), and then the concentration of Pb in the lead stripping solution was determined according to the Pb concentration in the lead stripping solution. 2+ With SO4 in sulfuric acid 2- The molar ratio is 1:1.2. Sulfuric acid (98%) is added to the lead-tin stripping solution and stirred for 15 minutes to generate lead sulfate precipitate. After standing and filtration, lead sulfate precipitate and tin-containing solution are obtained. (4) Adjust the pH of the tin-containing solution obtained in step (3) to 3-4, add sodium dodecyl sulfate (0.5 g / L) to the tin-containing solution, heat the tin-containing solution to 90°C, then turn on the micro-nano bubble generator (using air as the gas medium), adjust the air flow rate to 6 L / min, and inject micro-nano bubbles into the tin-containing solution. After 15 min, the Sn in the tin-containing solution... 2+ Complete catalytic oxidation to Sn 4+ After hydrolysis and filtration, Sn(OH)4 precipitate and filtrate are obtained. The Sn(OH)4 precipitate is then dried to obtain SnO2 powder, which is then recycled. (5) Then add 40g of methanesulfonic acid to the filtrate obtained in step (4), and turn on the micro-nano bubble generator again (using air as the gas medium), adjust the air flow rate to 10L / min, and inject micro-nano bubbles into the filtrate to remove Fe from the filtrate. 2+ Catalytic oxidation to Fe 3+ The ferric iron was regenerated by catalytic oxidation at room temperature for 20 minutes. Finally, the acidity of the filtrate was adjusted to its initial state by using methanesulfonic acid and the water produced in each process to make it recyclable for preparing the leaching solution.

[0057] In this embodiment, the recovery rate of copper is 99.5%, the recovery rate of tin is 98.5%, and the recovery rate of lead is 97.5%.

[0058] Example 5 This embodiment provides a green recycling method for extracting copper, tin, and lead from decommissioned photovoltaic solder ribbons, including the following steps: (1) The retired photovoltaic modules are pyrolyzed, physically crushed, sorted and cleaned to obtain photovoltaic welding strips; (2) Take 1000g of photovoltaic solder ribbon (of which the content of tin-lead Sn60 / Pb40 solderable coating is about 3wt%, that is, the mass of tin-lead Sn60 / Pb40 solderable coating to be removed is about 30g) and immerse it in 3L of leaching solution for detin-lead treatment. After immersion at room temperature for 20min, copper wire with tin-lead coating removed and detin-lead solution are obtained. The copper wire is then washed with water to obtain clean copper wire. The leaching solution is prepared by methanesulfonic acid, copper methanesulfonate and ferric sulfate, and the concentration of methanesulfonic acid is 50g / L, the concentration of copper methanesulfonate is 25g / L and the concentration of ferric sulfate is 70g / L. (3) The concentration of lead ions in the lead stripping solution obtained in step (2) was detected by ICP (inductively coupled plasma spectroscopy), and then the concentration of Pb in the lead stripping solution was determined according to the Pb concentration in the lead stripping solution. 2+ With SO4 in sulfuric acid 2- The molar ratio is 1:1.15. Sulfuric acid (98%) is added to the lead-tin stripping solution and stirred for 10 minutes to generate lead sulfate precipitate. After standing and filtration, lead sulfate precipitate and tin-containing solution are obtained. (4) Adjust the pH of the tin-containing solution obtained in step (3) to 3-4, add sodium dodecyl sulfate (1 g / L) to the tin-containing solution, heat the tin-containing solution to 80°C, then turn on the micro-nano bubble generator (using air as the gas medium), adjust the air flow rate to 6 L / min, and inject micro-nano bubbles into the tin-containing solution. After 15 min, the Sn in the tin-containing solution... 2+ Complete catalytic oxidation to Sn 4+ After hydrolysis and filtration, Sn(OH)4 precipitate and filtrate are obtained. The Sn(OH)4 precipitate is then dried to obtain SnO2 powder, which is then recycled. (5) Then add 50g of methanesulfonic acid to the filtrate obtained in step (4), and turn on the micro-nano bubble generator again (using air as the gas medium), adjust the air flow rate to 10L / min, and inject micro-nano bubbles into the filtrate to remove Fe from the filtrate. 2+ Catalytic oxidation to Fe 3+ Catalytic oxidation at 80℃ for 10 minutes regenerated ferric iron. Finally, the acidity of the filtrate was adjusted to its initial state using methanesulfonic acid and the water produced in each process, so that it could be recycled for preparing the leaching solution.

[0059] In this embodiment, the recovery rates are 99% for copper, 98% for tin, and 97% for lead.

[0060] Example 6 This embodiment provides a green recycling method for extracting copper, tin, and lead from decommissioned photovoltaic solder ribbons, including the following steps: (1) The retired photovoltaic modules are pyrolyzed, physically crushed, sorted and cleaned to obtain photovoltaic welding strips; (2) Take 1000g of photovoltaic solder ribbon (of which the content of tin-lead Sn60 / Pb40 solderable coating is about 3wt%, that is, the mass of tin-lead Sn60 / Pb40 solderable coating to be removed is about 30g) and immerse it in 3L of leaching solution for detin-lead treatment. After immersion at room temperature for 20min, copper wire with tin-lead coating removed and detin-lead solution are obtained. The copper wire is then washed with water to obtain clean copper wire. The leaching solution is prepared by acetic acid, copper methanesulfonate and ferric sulfate, and the concentration of acetic acid is 50g / L, the concentration of copper methanesulfonate is 25g / L and the concentration of ferric sulfate is 70g / L. (3) The concentration of lead ions in the lead stripping solution obtained in step (2) was detected by ICP (inductively coupled plasma spectroscopy), and then the concentration of Pb in the lead stripping solution was determined according to the Pb concentration in the lead stripping solution. 2+ With SO4 in sulfuric acid 2- The molar ratio is 1:1.2. Sulfuric acid (98%) is added to the lead-tin stripping solution and stirred for 10 minutes to generate lead sulfate precipitate. After standing and filtration, lead sulfate precipitate and tin-containing solution are obtained. (4) Adjust the pH of the tin-containing solution obtained in step (3) to 3-4, add octadecyltrimethylammonium chloride (concentration of 1 g / L) to the tin-containing solution, heat the tin-containing solution to 80°C, then turn on the micro-nano bubble generator (using air as the gas medium), adjust the air flow rate to 6 L / min, and inject micro-nano bubbles into the tin-containing solution. After 15 min, the Sn in the tin-containing solution... 2+ Complete catalytic oxidation to Sn 4+ After hydrolysis and filtration, Sn(OH)4 precipitate and filtrate are obtained. The Sn(OH)4 precipitate is then dried to obtain SnO2 powder, which is then recycled. (5) Then add 50g of acetic acid to the filtrate obtained in step (4), and turn on the micro-nano bubble generator again (using air as the gas medium), adjust the air flow rate to 10L / min, and inject micro-nano bubbles into the filtrate to remove Fe from the filtrate. 2+ Catalytic oxidation to Fe 3+ Catalytic oxidation at 80℃ for 10 minutes regenerated ferric iron. Finally, acetic acid and water from each process were used to wash the filtrate to adjust its acidity to the initial state, allowing it to be recycled for preparing the leachate.

[0061] In this embodiment, the recovery rates for copper, tin, and lead were 98%, 98%, and 97.5%, respectively.

[0062] Example 7 This embodiment provides a green recycling method for extracting copper, tin, and lead from decommissioned photovoltaic solder ribbons, including the following steps: (1) The retired photovoltaic modules are pyrolyzed, physically crushed, sorted and cleaned to obtain photovoltaic welding strips; (2) Take 1000g of photovoltaic solder ribbon (of which the content of tin-lead Sn60 / Pb40 solderable coating is about 3wt%, that is, the mass of tin-lead Sn60 / Pb40 solderable coating to be removed is about 30g) and immerse it in 5L of leaching solution for detin-lead treatment. After immersion at room temperature for 30min, copper wire with tin-lead coating removed and detin-lead solution are obtained. The copper wire is then washed with water to obtain clean copper wire. The leaching solution is prepared from methanesulfonic acid, copper acetate and ferric citrate, and the concentration of methanesulfonic acid is 15g / L, the concentration of copper acetate is 10g / L and the concentration of ferric citrate is 60g / L. (3) The concentration of lead ions in the lead stripping solution obtained in step (2) was detected by ICP (inductively coupled plasma spectroscopy), and then the concentration of Pb in the lead stripping solution was determined according to the Pb concentration in the lead stripping solution. 2+ With SO4 in sulfuric acid 2- The molar ratio is 1:1.1. Sulfuric acid (98%) is added to the lead-tin stripping solution and stirred for 10 minutes to generate lead sulfate precipitate. After standing and filtration, lead sulfate precipitate and tin-containing solution are obtained. (4) Adjust the pH of the tin-containing solution obtained in step (3) to 3-4, add octadecyltrimethylammonium chloride (concentration of 0.5 g / L) to the tin-containing solution, heat the tin-containing solution to 70°C, then turn on the micro-nano bubble generator (using air as the gas medium), adjust the air flow rate to 6 L / min, and inject micro-nano bubbles into the tin-containing solution. After 30 min, the Sn in the tin-containing solution... 2+ Complete catalytic oxidation to Sn 4+ After hydrolysis and filtration, Sn(OH)4 precipitate and filtrate are obtained. The Sn(OH)4 precipitate is then dried to obtain SnO2 powder, which is then recycled. (5) Then add 30g of methanesulfonic acid to the filtrate obtained in step (4), and turn on the micro-nano bubble generator again (using air as the gas medium), adjust the air flow rate to 10L / min, and inject micro-nano bubbles into the filtrate to remove Fe from the filtrate. 2+ Catalytic oxidation to Fe 3+ The ferric iron was regenerated by catalytic oxidation at room temperature for 30 minutes. Finally, the acidity of the filtrate was adjusted to its initial state by using methanesulfonic acid and the water produced in each process to make it recyclable for preparing the leachate.

[0063] In this embodiment, the recovery rates are 99% for copper, 98% for tin, and 97% for lead.

[0064] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the 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. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0065] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A stripping solution for extracting copper, tin, and lead from decommissioned photovoltaic solder strips, characterized in that, The stripping solution includes an leaching solution and a micro / nano bubble stabilizer; wherein the leaching solution includes an organic acid solution, an acidic copper salt, and an acidic ferric salt.

2. The stripping solution for extracting copper, tin, and lead from decommissioned photovoltaic solder strips according to claim 1, characterized in that, The organic acid solution includes at least one of methanesulfonic acid solution, aminosulfonic acid solution, and acetic acid solution; Optionally, in the stripping solution, the mass concentration of the organic acid solution is 20~100g / L.

3. The stripping solution for extracting copper, tin, and lead from decommissioned photovoltaic solder strips according to claim 1, characterized in that, The acidic copper salt includes at least one of copper acetate, copper methanesulfonate, and copper aminosulfonate; Optionally, the mass concentration of the acidic copper salt in the stripping solution is 15~150 g / L.

4. The stripping solution for extracting copper, tin, and lead from decommissioned photovoltaic solder strips according to claim 1, characterized in that, The acidic ferric salt includes at least one of ferric sulfate, ferric citrate, ferric ammonium sulfate, and ferric chloride; Optionally, in the stripping solution, the mass concentration of the acidic trivalent iron salt is 20~200 g / L.

5. The stripping solution for extracting copper, tin, and lead from decommissioned photovoltaic solder strips according to claim 1, characterized in that, The micro / nano bubble stabilizer includes at least one of octadecyltrimethylammonium chloride, hexadecyltrimethylammonium bromide, and sodium dodecyl sulfate; Optionally, the mass concentration of the micro / nano bubble stabilizer in the stripping solution is 0.5~1g / L.

6. A green recycling method for extracting copper, tin, and lead from decommissioned photovoltaic solder ribbons using the stripping solution according to any one of claims 1-5, characterized in that, Includes the following steps: (1) The retired photovoltaic modules are pyrolyzed, physically crushed, sorted and cleaned to obtain photovoltaic welding strips; (2) The photovoltaic solder ribbon is immersed in a leaching solution for detinning and lead removal to obtain copper wire and detinning and lead removal solution, and the copper wire is cleaned to obtain clean copper wire; the leaching solution is the leaching solution described in claim 1; (3) Add sulfuric acid to the lead-free solution obtained in step (2) to generate lead sulfate precipitate, and then separate the solid and liquid to obtain lead sulfate precipitate and tin-containing solution; (4) Adjust the pH of the tin-containing solution obtained in step (3) to 3-4, add a micro / nano bubble stabilizer to the tin-containing solution, and heat it. Then inject micro / nano bubbles into the tin-containing solution to reduce the Sn concentration in the tin-containing solution. 2+ Catalytic oxidation to Sn 4+ After hydrolysis and filtration, Sn(OH)4 precipitate and filtrate are obtained. The precipitate is then dried to obtain SnO2 powder. (5) Add organic acid to the filtrate obtained in step (4) and inject micro-nano bubbles to remove Fe from the filtrate. 2+ Catalytic oxidation to Fe 3+ This process regenerates ferric iron, and finally, the acidity of the filtrate is adjusted so that it can be recycled for preparing the leachate.

7. The green recycling method for extracting copper, tin, and lead from decommissioned photovoltaic welding strips according to claim 6, characterized in that, In step (1), the content of the tin-lead solderability coating on the surface of the photovoltaic solder ribbon is 3wt% to 5wt%, the tin-lead alloy composition is Sn60 / Pb40, and the thickness of the tin-lead coating is 2 to 5 μm.

8. The green recycling method for extracting copper, tin, and lead from decommissioned photovoltaic solder ribbons according to claim 6, characterized in that, In step (2), the soaking temperature is room temperature and the soaking time is 10~40 minutes.

9. The green recycling method for extracting copper, tin, and lead from decommissioned photovoltaic welding strips according to claim 6, characterized in that, In step (4), the temperature of the heat treatment is 50~90℃; And / or, the Sn 2+ Catalytic oxidation to Sn 4+ The time is 10~60 minutes.

10. The green recycling method for extracting copper, tin, and lead from decommissioned photovoltaic solder ribbons according to claim 6, characterized in that, In step (5), the Fe 2+ Catalytic oxidation to Fe 3+ The time is 10~30 minutes.

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