Method for separating and recovering copper, indium, gallium and selenium from waste thin film solar cell

Abstract

The invention belongs to the field of resource regeneration, and particularly relates to a method for separating and recycling copper, indium, gallium and selenium from a waste solar thin film battery. According to the method, the waste solar thin film cells are subjected to oxidizing roasting, deep eutectic leaching and extraction and reverse extraction, and high-quality conversion and purification of all valuable elements in the waste solar thin film cells to oxides of the valuable elements are achieved. According to the method, the process route is simple, high-selectivity extraction of indium is achieved through the synergistic effect of the deep eutectic solvent and P204, and meanwhile effective recovery of valuable elements such as copper and selenium is achieved. The recovered and prepared oxide can be widely applied to strategic emerging industries such as semiconductors, photovoltaics, aerospace, military and the like.

Description

Technical Field

[0001] This invention belongs to the field of resource recycling, specifically relating to a method for separating and recovering copper, indium, gallium and selenium from waste solar thin-film batteries. Background Technology

[0002] CIGS (CuInGaSe2), as a core material for next-generation thin-film solar cells, has attracted widespread attention due to its advantages such as strong light absorption, good power generation stability, high conversion efficiency, long daytime power generation time, high power output, low production cost, and short energy recovery cycle. With the first batch of commercially available CIGS modules entering their typical end-of-life cycle (8-12 years), the amount of waste batteries generated is growing exponentially. The main components of waste thin-film solar cells are high-value strategic metals such as copper, indium, gallium, and selenium. Faced with the wave of photovoltaic industry obsolescence, developing efficient CIGS recycling technology is of urgent significance for ensuring strategic resource security, reducing ecotoxicity, and achieving a circular economy. However, indium and gallium, both belonging to Group IIIA elements, have highly similar ionic radii and charge densities, leading to three major technical bottlenecks in traditional separation processes: selectivity, high co-extraction rate, and mutually exclusive indium-gallium recovery rates, severely restricting resource utilization efficiency. Therefore, breakthroughs in indium-gallium deep separation technology are an urgent need for achieving efficient CIGS recycling.

[0003] Chinese patent application CN102296178A discloses a method for recovering copper indium gallium selenide (CIGS). This method mainly utilizes a mixed solution of hydrochloric acid and hydrogen peroxide to dissolve the metal powder containing CIGS. After separating selenium using hydrazine, copper is replaced by indium metal. Finally, indium and gallium are separated using a supported liquid film combined with a dispersed back-extraction solution. Chinese patent application CN103184388A discloses another method for recovering CIGS. This method first breaks a CIGS thin-film solar panel into fragments, then places these fragments in a mixed solution of sulfuric acid and hydrogen peroxide at a specific temperature for a predetermined time to obtain a leachate. Subsequently, indium, gallium, and selenium are recovered from the leachate through extraction, back-extraction, and electrolysis processes.

[0004] US Patent No. 5779877 discloses a method for recycling copper indium gallium selenide (CIGS) solar cell waste. The method mainly includes crushing, nitric acid leaching, two-electrode electrolytic separation of copper, selenium, and indium, followed by evaporation and decomposition to obtain a mixture of indium and zinc oxides, and oxidative distillation to separate copper and selenium. Patent CN201610039562 discloses a method for recycling CIGS, which mainly includes sulfation roasting, sulfuric acid dissolution, extraction electrolysis of metallic copper, production of gallium hydroxide precipitate, and indium replacement. In the above-mentioned prior art, the use of large amounts of acidic reagents in the roasting and leaching stages easily causes acid gas pollution. Simultaneously, the extractant used in indium extraction causes co-extraction of gallium, making indium and gallium separation difficult, thus reducing the recovery rate of indium and gallium. Furthermore, the indium-copper replacement method is too costly. To overcome the above-mentioned deficiencies in the prior art, the purpose of this invention is to provide a method for recycling CIGS that can reduce environmental pollution, achieve a high recovery rate, and have a low production cost. Summary of the Invention

[0005] To address the aforementioned problems, this invention proposes a method for separating and recovering copper, indium, gallium, and selenium from spent solar thin-film batteries. This method first recovers selenium through an oxidative roasting process, which eliminates the need for acid or alkali addition, effectively solving the problems of selenide volatilization and acidic waste gas emissions inherent in traditional recovery methods. Subsequently, leaching is performed using a recyclable deep eutectic reagent, which offers excellent leaching performance at a low cost. In the leachate treatment stage, the selectivity of P2O4 successfully achieves efficient separation of indium and gallium, resolving the co-extraction problem in the extraction process and significantly improving the recovery rates of indium and gallium. The recovered high-purity indium oxide, gallium oxide, selenium oxide, and copper oxide products can be widely applied in strategic emerging industries such as semiconductors, photovoltaics, aerospace, and military. This process boasts significant advantages such as simplicity, high efficiency in indium and gallium separation, and excellent product purity.

[0006] This invention provides a method for separating and recovering copper, indium, gallium, and selenium from waste solar thin-film batteries, comprising the following steps:

[0007] (1) Oxidative roasting: Waste solar thin-film batteries are roasted in a tubular furnace to obtain roasting residue. The roasting temperature is 800-1000℃ and the roasting time is 2-4 hours.

[0008] (2) Deep eutectic configuration: Hydrogen bond acceptor, hydrogen bond ligand and deionized water are mixed evenly to obtain deep eutectic solvent;

[0009] (3) Wet leaching: The deep eutectic solvent obtained in step (2) is used to wet leach the roasted residue obtained in step (1) to obtain a deep eutectic leachate;

[0010] (4) Indium extraction: The leachate of the deep eutectic solution obtained in step (3) is extracted to obtain the deep eutectic extract containing copper and gallium and the indium-loaded organic phase;

[0011] (5) Indium back-extraction: The loaded indium organic phase obtained in step (4) is back-extracted to obtain an empty indium organic phase and an indium chloride solution. The empty indium organic phase is returned to the indium extraction process. Hydrochloric acid is used as the back-extraction agent with a concentration of 3.0 mol / L. The O / A ratio of back-extraction is 1:1. The back-extraction temperature is 25℃, the extraction time is 5 min, and the number of back-extraction stages is 1.

[0012] (6) Copper extraction: The deep eutectic extract containing copper and gallium obtained in step (4) is extracted to obtain a gallium-containing deep eutectic extract and a copper-loaded organic phase.

[0013] (7) Copper back-extraction: The copper-loaded organic phase obtained in step (6) is back-extracted to obtain an empty copper organic phase and a copper sulfate solution. The empty copper organic phase is returned to the copper extraction process. Sulfuric acid is used as the back-extraction agent with a concentration of 2.0 mol / L. The O / A ratio of back-extraction is 1:1. The back-extraction temperature is 25℃, the extraction time is 5 min, and the number of back-extraction stages is 1.

[0014] (8) Precipitation and calcination: The gallium-containing deep eutectic extraction residue obtained in step (6) is precipitated to obtain precipitate and precipitate residue. The precipitate is centrally processed, and the precipitate residue is calcined to obtain gallium oxide products. The indium chloride solution and copper sulfate solution obtained in steps (5) and (7) are pH adjusted to obtain different precipitates. After calcination, indium oxide and copper oxide products are obtained respectively.

[0015] Furthermore, in step (2), the hydrogen bond acceptor is choline chloride or polyethylene glycol, the hydrogen bond donor is oxalic acid, formic acid, lactic acid, citric acid or tartaric acid, the molar ratio of hydrogen bond acceptor to hydrogen bond donor is 3:1-1:3, the water content is 20% to 60%, the temperature is 50-90℃, the stirring speed is 400 r / min, and the stirring time is 30 min.

[0016] Furthermore, the leaching time in step (3) is 6-10 hours, the leaching temperature is 50-90°C, and the leaching liquid-to-solid ratio is 40-80 mL / g.

[0017] Furthermore, in step (4), the extractant is P204, kerosene is used as the diluent, the volume ratio of P204 to kerosene is 1:1-1:5, the O / A ratio is 1:1-1:4, the extraction temperature is 20-40℃, the extraction time is 3-5 min, and the extraction stage is 1-4.

[0018] Furthermore, in step (6), the extractant is Lix84, the diluent is kerosene, the volume ratio of Lix84 to kerosene is 1:1-1:5, the O / A ratio is 1:1-1:4, the extraction temperature is 20-40℃, the extraction time is 5-10 min, and the extraction stage is 1-5.

[0019] The present invention has the following beneficial effects:

[0020] (1) Selenium is recovered by oxidative roasting process. This process does not require the addition of acids or alkalis, reducing the volatilization of selenium compounds and the emission of acidic waste gas;

[0021] (2) The calcined residue was treated with a deep eutectic reagent to achieve effective leaching of copper, indium and gallium;

[0022] (3) The problem of indium gallium co-extraction was solved by coupling deep eutectic solvent with extractant P204. Attached Figure Description

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0024] Figure 1 A flowchart for separating and recovering copper, indium, gallium, and selenium from waste solar thin-film batteries. Detailed Implementation

[0025] Various exemplary embodiments of the present invention are now described in detail. Unless otherwise specified, the methods used in the embodiments are conventional methods, and the reagents used are commercially available reagents or reagents prepared using conventional methods. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, characteristics, and embodiments of the present invention.

[0026] It should be understood that the terms described herein are intended only to describe particular embodiments and are not intended to limit the present invention. In addition, for numerical ranges herein, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. The intermediate value within any stated value or stated range, and each smaller range between any other stated value or intermediate value within the stated range, is also encompassed within the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded within the scope.

[0027] Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of any conflict with any incorporated document, the contents of this specification shall prevail.

[0028] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments described herein without departing from the scope or spirit of the invention. Other embodiments will be apparent to those skilled in the art from the description of the invention. The description and examples are intended to be illustrative only.

[0029] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0030] Example 1

[0031] (1) Oxidative roasting: Waste solar thin-film batteries are roasted in a tubular furnace to obtain roasting residue and volatile gas condensation product selenium oxide. The roasting temperature is 950℃ and the roasting time is 4 hours.

[0032] (2) Deep eutectic configuration: Hydrogen bond acceptor, hydrogen bond ligand and deionized water are mixed evenly in a certain proportion to prepare deep eutectic solvent, wherein the hydrogen bond acceptor is choline chloride, the hydrogen bond donor is oxalic acid, the molar ratio of hydrogen bond acceptor to hydrogen bond donor is 2:1, the water content is 20%, the temperature is 90℃, the stirring speed is 400r / min, and the stirring time is 30min.

[0033] (3) Wet leaching: The deep eutectic solvent obtained in step (2) is used to wet leach the roasted residue obtained in step (1) to obtain a deep eutectic leachate. The leaching temperature is 90℃, the leaching time is 8h, and the liquid-solid ratio is 60mL / g to obtain a deep eutectic solution leachate.

[0034] (4) Indium extraction: The deep eutectic solution leachate was extracted to obtain a deep eutectic extract containing copper and gallium and an indium-loaded organic phase. P204 was used as the extractant and kerosene was used as the diluent. The volume ratio of P204 to kerosene was 1:2, the O / A ratio of the extract was 1:2, the extraction temperature was 25℃, the extraction time was 5min, and the extraction stage was 1.

[0035] (5) Indium back-extraction: The obtained indium-loaded organic phase is back-extracted to obtain an empty indium-loaded organic phase and an indium chloride solution. The empty indium-loaded organic phase is returned to the indium extraction process. Hydrochloric acid is used as the back-extraction agent with a concentration of 3.0 mol / L. The O / A ratio of back-extraction is 1:1. The back-extraction temperature is 25℃, the extraction time is 5 min, and the number of back-extraction stages is 1.

[0036] (6) Copper extraction: The deep eutectic raffinate containing copper and gallium was subjected to copper extraction to obtain gallium-rich raffinate and copper-loaded organic phase. Lix84 was used as the extractant and kerosene was used as the diluent. The volume ratio of Lix84 to kerosene was 1:3, the O / A ratio was 1:1, the extraction temperature was 25℃, the extraction time was 5 min, and the extraction stage was 3.

[0037] (7) Copper back-extraction: The copper-loaded organic phase obtained in step (6) is back-extracted to obtain an empty copper organic phase and a copper sulfate solution. The empty copper organic phase is returned to the copper extraction process. Sulfuric acid is used as the back-extraction agent with a concentration of 2.0 mol / L. The O / A ratio of back-extraction is 1:1. The back-extraction temperature is 25℃, the extraction time is 5 min, and the number of back-extraction stages is 1.

[0038] (8) Precipitation and calcination: The gallium-containing deep eutectic extraction residue obtained in step (6) is precipitated to obtain precipitate and precipitate residue. The precipitate is centrally processed, and the precipitate residue is calcined to obtain gallium oxide products. The indium chloride solution and copper sulfate solution obtained in steps (5) and (7) are pH adjusted to obtain different precipitates. After calcination, indium oxide and copper oxide products are obtained respectively.

[0039] In this embodiment, the recovery rates of copper, indium, gallium, and selenium were 99.15%, 99.51%, 99.22%, and 99.52%, respectively, and the purities of copper oxide, indium oxide, gallium oxide, and selenium oxide were 98.77%, 99.23%, 99.33%, and 97.28%, respectively.

[0040] Example 2

[0041] (1) Oxidative roasting: Waste solar thin-film batteries are roasted in a tubular furnace to obtain roasting residue and volatile gas condensation product selenium oxide. The roasting temperature is 950℃ and the roasting time is 2 hours.

[0042] (2) Deep eutectic configuration: Hydrogen bond acceptor, hydrogen bond ligand and deionized water are mixed evenly in a certain proportion to prepare deep eutectic solvent, wherein the hydrogen bond acceptor is choline chloride, the hydrogen bond donor is formic acid, the molar ratio of hydrogen bond acceptor and hydrogen bond donor is 1:1, the water content is 25%, the temperature is 70℃, the stirring speed is 400r / min, and the stirring time is 30min.

[0043] (3) Wet leaching: The deep eutectic solvent obtained in step (2) is used to wet leach the roasted residue obtained in step (1) to obtain a deep eutectic leachate. The leaching temperature is 70℃, the leaching time is 6h, and the liquid-solid ratio is 50mL / g to obtain a deep eutectic solution leachate.

[0044] (4) Indium extraction: The deep eutectic solution leachate was extracted to obtain a deep eutectic extract containing copper and gallium and an indium-loaded organic phase. P204 was used as the extractant and kerosene was used as the diluent. The volume ratio of P204 to kerosene was 1:3, the O / A ratio was 1:1, the extraction temperature was 20℃, the extraction time was 3 min, and the extraction stage was 2.

[0045] (5) Indium back-extraction: The obtained indium-loaded organic phase is back-extracted to obtain an empty indium-loaded organic phase and an indium chloride solution. The empty indium-loaded organic phase is returned to the indium extraction process. Hydrochloric acid is used as the back-extraction agent with a concentration of 3.0 mol / L. The O / A ratio of back-extraction is 1:1. The back-extraction temperature is 25℃, the extraction time is 5 min, and the number of back-extraction stages is 1.

[0046] (6) Copper extraction: The deep eutectic raffinate containing copper and gallium was subjected to copper extraction to obtain gallium-rich raffinate and copper-loaded organic phase. Lix84 was used as the extractant and kerosene was used as the diluent. The volume ratio of Lix84 to kerosene was 1:4, the O / A ratio was 1:2, the extraction temperature was 25℃, the extraction time was 8 min, and the extraction stage was 1.

[0047] (7) Copper back-extraction: The copper-loaded organic phase obtained in step (6) is back-extracted to obtain an empty copper organic phase and a copper sulfate solution. The empty copper organic phase is returned to the copper extraction process. Sulfuric acid is used as the back-extraction agent with a concentration of 2.0 mol / L. The O / A ratio of back-extraction is 1:1. The back-extraction temperature is 25℃, the extraction time is 5 min, and the number of back-extraction stages is 1.

[0048] (8) Precipitation and calcination: The gallium-containing deep eutectic extraction residue obtained in step (6) is precipitated to obtain precipitate and precipitate residue. The precipitate is centrally processed, and the precipitate residue is calcined to obtain gallium oxide products. The indium chloride solution and copper sulfate solution obtained in steps (5) and (7) are pH adjusted to obtain different precipitates. After calcination, indium oxide and copper oxide products are obtained respectively.

[0049] In this embodiment, the recovery rates of copper, indium, gallium, and selenium were 85.45%, 89.32%, 93.23%, and 99.34%, respectively, and the purities of copper oxide, indium oxide, gallium oxide, and selenium oxide were 98.68%, 99.45%, 99.01%, and 98.99%, respectively.

[0050] Example 3

[0051] (1) Oxidative roasting: Waste solar thin-film batteries are roasted in a tubular furnace to obtain roasting residue and volatile gas condensation product selenium oxide. The roasting temperature is 850℃ and the roasting time is 4 hours.

[0052] (2) Deep eutectic configuration: Hydrogen bond acceptor, hydrogen bond ligand and deionized water are mixed evenly in a certain proportion to prepare deep eutectic solvent, wherein the hydrogen bond acceptor is polyethylene glycol, the hydrogen bond donor is tartaric acid, the molar ratio of hydrogen bond acceptor to hydrogen bond donor is 3:1, the water content is 35%, the temperature is 80℃, the stirring speed is 400r / min, and the stirring time is 30min;

[0053] (3) Wet leaching: The deep eutectic solvent obtained in step (2) is used to wet leach the roasted residue obtained in step (1) to obtain a deep eutectic leachate. The leaching temperature is 80℃, the leaching time is 8h, and the liquid-solid ratio is 60mL / g to obtain a deep eutectic solution leachate.

[0054] (4) Indium extraction: The deep eutectic solution leachate was extracted to obtain a deep eutectic extract containing copper and gallium and an indium-loaded organic phase. P204 was used as the extractant and kerosene was used as the diluent. The volume ratio of P204 to kerosene was 1:2, the O / A ratio was 1:1, the extraction temperature was 30℃, the extraction time was 4 min, and the extraction stage was 4.

[0055] (5) Indium back-extraction: The obtained indium-loaded organic phase is back-extracted to obtain an empty indium-loaded organic phase and an indium chloride solution. The empty indium-loaded organic phase is returned to the indium extraction process. Hydrochloric acid is used as the back-extraction agent with a concentration of 3.0 mol / L. The O / A ratio of back-extraction is 1:1. The back-extraction temperature is 25℃, the extraction time is 5 min, and the number of back-extraction stages is 1.

[0056] (6) Copper extraction: The deep eutectic raffinate containing copper and gallium was subjected to copper extraction to obtain gallium-rich raffinate and copper-loaded organic phase. Lix84 was used as the extractant and kerosene was used as the diluent. The volume ratio of Lix84 to kerosene was 1:5, the O / A ratio was 1:4, the extraction temperature was 25℃, the extraction time was 10 min, and the extraction stage was 4.

[0057] (7) Copper back-extraction: The copper-loaded organic phase obtained in step (6) is back-extracted to obtain an empty copper organic phase and a copper sulfate solution. The empty copper organic phase is returned to the copper extraction process. Sulfuric acid is used as the back-extraction agent with a concentration of 2.0 mol / L. The O / A ratio of back-extraction is 1:1. The back-extraction temperature is 25℃, the extraction time is 5 min, and the number of back-extraction stages is 1.

[0058] (8) Precipitation and calcination: The gallium-containing deep eutectic extraction residue obtained in step (5) is precipitated to obtain precipitate and precipitate residue. The precipitate is centrally processed, and the precipitate residue is calcined to obtain gallium oxide products. The indium chloride solution and copper sulfate solution obtained in steps (5) and (7) are pH adjusted to obtain different precipitates. After calcination, indium oxide and copper oxide products are obtained respectively.

[0059] In this embodiment, the recovery rates of copper, indium, gallium, and selenium were 90.23%, 93.23%, 96.45%, and 89.12%, respectively, and the purities of copper oxide, indium oxide, gallium oxide, and selenium oxide were 98.45%, 99.78%, 99.12%, and 98.12%, respectively.

[0060] Example 4

[0061] (1) Oxidative roasting: Waste solar thin-film batteries are roasted in a tubular furnace to obtain roasting residue and volatile gas condensation product selenium oxide. The roasting temperature is 900℃ and the roasting time is 3 hours.

[0062] (2) Deep eutectic configuration: Hydrogen bond acceptor, hydrogen bond ligand and deionized water are mixed evenly in a certain proportion to prepare deep eutectic solvent, wherein the hydrogen bond acceptor is choline chloride, the hydrogen bond donor is citric acid, the molar ratio of hydrogen bond acceptor and hydrogen bond donor is 1:1, the water content is 40%, the temperature is 90℃, the stirring speed is 400r / min, and the stirring time is 30min.

[0063] (3) Wet leaching: The deep eutectic solvent obtained in step (2) is used to wet leach the calcined residue obtained in step (1) to obtain a deep eutectic leachate. The leaching temperature is 90℃, the leaching time is 10h, and the liquid-solid ratio is 60mL / g to obtain a deep eutectic solution leachate.

[0064] (4) Indium extraction: The deep eutectic solution leachate was extracted to obtain a deep eutectic extract containing copper and gallium and an indium-loaded organic phase. P204 was used as the extractant and kerosene was used as the diluent. The volume ratio of P204 to kerosene was 1:3, the O / A ratio was 1:1, the extraction temperature was 35℃, the extraction time was 4 min, and the number of extraction stages was 2.

[0065] (5) Indium back-extraction: The obtained indium-loaded organic phase is back-extracted to obtain an empty indium-loaded organic phase and an indium chloride solution. The empty indium-loaded organic phase is returned to the indium extraction process. Hydrochloric acid is used as the back-extraction agent with a concentration of 3.0 mol / L. The O / A ratio of back-extraction is 1:1. The back-extraction temperature is 25℃, the extraction time is 5 min, and the number of back-extraction stages is 1.

[0066] (6) Copper extraction: The deep eutectic raffinate containing copper and gallium was subjected to copper extraction to obtain gallium-rich raffinate and copper-loaded organic phase. Lix84 was used as the extractant and kerosene was used as the diluent. The volume ratio of Lix84 to kerosene was 1:3, the O / A ratio was 1:1, the extraction temperature was 25℃, the extraction time was 7 min, and the number of extraction stages was 2.

[0067] (7) Copper back-extraction: The copper-loaded organic phase obtained in step (6) is back-extracted to obtain an empty copper organic phase and a copper sulfate solution. The empty copper organic phase is returned to the copper extraction process. Sulfuric acid is used as the back-extraction agent with a concentration of 2.0 mol / L. The O / A ratio of back-extraction is 1:1. The back-extraction temperature is 25℃, the extraction time is 5 min, and the number of back-extraction stages is 1.

[0068] (8) Precipitation and calcination: The gallium-containing deep eutectic extraction residue obtained in step (6) is precipitated to obtain precipitate and precipitate residue. The precipitate is centrally processed, and the precipitate residue is calcined to obtain gallium oxide products. The indium chloride solution and copper sulfate solution obtained in steps (5) and (7) are pH adjusted to obtain different precipitates. After calcination, indium oxide and copper oxide products are obtained respectively.

[0069] In this embodiment, the recovery rates of copper, indium, gallium, and selenium were 85.34%, 89.31%, 93.12%, and 99.32%, respectively, and the purities of copper oxide, indium oxide, gallium oxide, and selenium oxide were 99.03%, 99.51%, 99.12%, and 99.23%, respectively.

[0070] Example 5

[0071] (1) Oxidative roasting: Waste solar thin-film batteries are roasted in a tubular furnace to obtain roasting residue and volatile gas condensation product selenium oxide. The roasting temperature is 700℃ and the roasting time is 1 hour.

[0072] (2) Deep eutectic configuration: Hydrogen bond acceptor, hydrogen bond ligand and deionized water are mixed evenly in a certain proportion to prepare deep eutectic solvent, wherein the hydrogen bond acceptor is polyethylene glycol, the hydrogen bond donor is lactic acid, the molar ratio of hydrogen bond acceptor and hydrogen bond donor is 1:2, the water content is 30%, the temperature is 50℃, the stirring speed is 400r / min, and the stirring time is 30min.

[0073] (3) Wet leaching: The deep eutectic solvent obtained in step (2) is used to wet leach the calcined residue obtained in step (1) to obtain a deep eutectic leachate. The leaching temperature is 50℃, the leaching time is 6h, and the liquid-solid ratio is 40mL / g to obtain a deep eutectic solution leachate.

[0074] (4) Indium extraction: The deep eutectic solution leachate was extracted to obtain a deep eutectic extract containing copper and gallium and an indium-loaded organic phase. P204 was used as the extractant and kerosene was used as the diluent. The volume ratio of P204 to kerosene was 1:5, the O / A ratio was 1:3, the extraction temperature was 40℃, the extraction time was 5 min, and the extraction stage was 1.

[0075] (5) Indium back-extraction: The obtained indium-loaded organic phase is back-extracted to obtain an empty indium-loaded organic phase and an indium chloride solution. The empty indium-loaded organic phase is returned to the indium extraction process. Hydrochloric acid is used as the back-extraction agent with a concentration of 3.0 mol / L. The O / A ratio of back-extraction is 1:1. The back-extraction temperature is 25℃, the extraction time is 5 min, and the number of back-extraction stages is 1.

[0076] (6) Copper extraction: The deep eutectic raffinate containing copper and gallium was subjected to copper extraction to obtain gallium-rich raffinate and copper-loaded organic phase. Lix84 was used as the extractant and kerosene was used as the diluent. The volume ratio of Lix84 to kerosene was 1:4, the O / A ratio was 1:3, the extraction temperature was 25℃, the extraction time was 6 min, and the extraction stage was 1.

[0077] (7) Copper back-extraction: The copper-loaded organic phase obtained in step (6) is back-extracted to obtain an empty copper organic phase and a copper sulfate solution. The empty copper organic phase is returned to the copper extraction process. Sulfuric acid is used as the back-extraction agent with a concentration of 2.0 mol / L. The O / A ratio of back-extraction is 1:1. The back-extraction temperature is 25℃, the extraction time is 5 min, and the number of back-extraction stages is 1.

[0078] (8) Precipitation and calcination: The gallium-containing deep eutectic extraction residue obtained in step (6) is precipitated to obtain precipitate and precipitate residue. The precipitate is centrally processed, and the precipitate residue is calcined to obtain gallium oxide products. The indium chloride solution and copper sulfate solution obtained in steps (5) and (7) are pH adjusted to obtain different precipitates. After calcination, indium oxide and copper oxide products are obtained respectively.

[0079] In this embodiment, the recovery rates of copper, indium, gallium, and selenium were 53.33%, 65.33%, 70.02%, and 50.23%, respectively, and the purities of copper oxide, indium oxide, gallium oxide, and selenium oxide were 99.03%, 99.03%, 99.21%, and 97.88%, respectively.

[0080] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A method for separating and recovering copper, indium, gallium, and selenium from waste solar thin-film batteries, characterized in that, Includes the following steps: (1) Oxidative roasting: Waste solar thin-film batteries are roasted in a tubular furnace to obtain roasting residue. The roasting temperature is 800-1000℃ and the roasting time is 2-4 hours. (2) Deep eutectic configuration: Hydrogen bond acceptor, hydrogen bond ligand and deionized water are mixed evenly to obtain deep eutectic solvent; (3) Wet leaching: The deep eutectic solvent obtained in step (2) is used to wet leach the roasted residue obtained in step (1) to obtain a deep eutectic leachate; (4) Indium extraction: The leachate of the deep eutectic solution obtained in step (3) is extracted to obtain the deep eutectic extract containing copper and gallium and the indium-loaded organic phase; (5) Indium back-extraction: The loaded indium organic phase obtained in step (4) is back-extracted to obtain an empty indium organic phase and an indium chloride solution. The empty indium organic phase is returned to the indium extraction process. Hydrochloric acid is used as the back-extraction agent with a concentration of 3.0 mol / L. The O / A ratio of back-extraction is 1:

1. The back-extraction temperature is 25℃, the extraction time is 5 min, and the number of back-extraction stages is 1. (6) Copper extraction: The deep eutectic extract containing copper and gallium obtained in step (4) is extracted to obtain a gallium-containing deep eutectic extract and a copper-loaded organic phase. (7) Copper back-extraction: The copper-loaded organic phase obtained in step (6) is back-extracted to obtain an empty copper organic phase and a copper sulfate solution. The empty copper organic phase is returned to the copper extraction process. Sulfuric acid is used as the back-extraction agent with a concentration of 2.0 mol / L. The O / A ratio of back-extraction is 1:

1. The back-extraction temperature is 25℃, the extraction time is 5 min, and the number of back-extraction stages is 1. (8) Precipitation and calcination: The gallium-containing deep eutectic extraction residue obtained in step (6) is precipitated to obtain precipitate and precipitate residue. The precipitate is centrally processed, and the precipitate residue is calcined to obtain gallium oxide products. The indium chloride solution and copper sulfate solution obtained in steps (5) and (7) are pH adjusted to obtain different precipitates. After calcination, indium oxide and copper oxide products are obtained respectively.

2. The method according to claim 1, characterized in that, The hydrogen bond acceptor in step (2) is choline chloride or polyethylene glycol, the hydrogen bond donor is oxalic acid, formic acid, lactic acid, citric acid or tartaric acid, the molar ratio of hydrogen bond acceptor to hydrogen bond donor is 3:1-1:3, the water content is 20% to 60%, the temperature is 50-90℃, the stirring speed is 400 r / min, and the stirring time is 30 min.

3. The method according to claim 1, characterized in that, The leaching time in step (3) is 6-10 hours, the leaching temperature is 50-90℃, and the leaching liquid-to-solid ratio is 40-80 mL / g.

4. The method according to claim 1, characterized in that, The extractant in step (4) is P204, and kerosene is used as the diluent. The volume ratio of P204 to kerosene is 1:1-1:5, the O / A ratio is 1:1-1:4, the extraction temperature is 20-40℃, the extraction time is 3-5 min, and the extraction stage is 1-4.

5. The method according to claim 1, characterized in that, The extractant in step (6) is Lix84, the diluent is kerosene, the volume ratio of Lix84 to kerosene is 1:1-1:5, the O / A ratio is 1:1-1:4, the extraction temperature is 20-40℃, the extraction time is 5-10 min, and the extraction stage is 1-5.

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