Silver removal method for preparing electrolyte for high-purity copper
By adding sulfide reagents and controlling the reaction conditions during copper electrolysis, negative divalent sulfur ions are generated to precipitate silver ions, solving the problem of excessive silver content in high-purity copper. This achieves efficient and green deep silver removal, improving the purity of copper products.
Patent Information
- Application Number
- CN202511619611.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-06
- Publication Date
- 2026-04-14
AI Technical Summary
In the process of preparing high-purity copper, the silver content in the cathode copper is too high, which leads to economic losses for copper smelting enterprises and is difficult to remove effectively. Traditional methods are inefficient.
Sulfide-based silver removal agents, such as carbon disulfide, methyl xanthate, thioacetaldehyde, and thiourea, are added during the electrolysis process. By controlling the reaction temperature and the composition of the copper electrolyte, divalent sulfur ions are generated, which deeply precipitate silver ions. The silver impurities are then removed by filtration using a 0.22μm microporous membrane.
It achieves efficient and green deep silver removal, improves the purity of high-purity copper products, meets the GB/T 26017-2020 standard, and avoids the introduction of impurity ions in copper electrolyte.
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Figure CN121853068A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a method for removing silver from an electrolyte used in the preparation of high-purity copper, belonging to the field of non-ferrous metal hydrometallurgical technology. Background Technology
[0002] High-purity copper refers to metallic copper with a copper content of 99.999% or higher. It is widely used in electronics, semiconductors, display panels, new energy, and communications. Its excellent electrical and thermal conductivity make it a key material in the manufacture of integrated circuits, liquid crystal displays, high-performance cables, and precision instruments, and it is crucial for improving product performance and reliability.
[0003] A typical technical challenge in the electrolytic or electrowinning refining process for producing high-purity copper of 5N and above is the excessively high silver content in the resulting cathode copper. This high silver content not only leads to economic losses for copper smelting companies, as silver is far more expensive than copper and is not priced when the cathode copper is sold, but also makes silver the most difficult metallic impurity element to remove during the production of 5N and above high-purity copper. Reducing the silver content in cathode copper is crucial for improving the quality of cathode copper products and for the recovery of precious metals. Currently, the main methods for reducing the silver content in electrolytic cathode copper include controlling the mechanical inclusion of floating anode mud in the cathode copper and reducing the entry of free silver ions into the cathode copper through deep extraction of free silver ions from the copper electrolyte. However, these methods are inefficient in removing silver and cannot achieve dynamic silver removal. Therefore, this invention proposes a method for efficiently removing silver from the electrolyte during electrolytic copper refining by adding sulfide-based silver removal agents. Summary of the Invention
[0004] To address the problem of low silver removal efficiency in current copper refining electrolytes, this invention provides a method for removing silver from an electrolyte used in the preparation of high-purity copper. The specific process flow diagram is shown below. Figure 1 As shown, it has the advantages of high efficiency, greenness, and deep silver removal.
[0005] The purpose of this invention is to provide a method for removing silver from an electrolyte used in the preparation of high-purity copper, specifically including the following steps: (1) During the electrolysis process, the electrolyte for preparing high-purity copper is extracted from the electrolysis device, and the silver removal agent is added to the electrolyte for preparing high-purity copper. Then the reaction is stirred to obtain the electrolyte for preparing high-purity copper after the reaction.
[0006] (2) The electrolyte for preparing high-purity copper after the reaction is precisely filtered, and the resulting filtrate is the electrolyte for preparing high-purity copper after silver removal.
[0007] Preferably, the electrolyte used to prepare high-purity copper in step (1) is copper sulfate electrolyte or copper nitrate electrolyte; when copper sulfate electrolyte is used as the electrolyte for preparing high-purity copper, the concentration of sulfuric acid in the electrolyte is 80-120 g / L, the concentration of copper ions is 60 g / L, and the concentration of chloride ions is 0.05-0.4 g / L; when copper nitrate electrolyte is used as the electrolyte for preparing high-purity copper, the concentration of nitric acid in the electrolyte is 2-50 g / L, the concentration of copper ions is 50 g / L, and the concentration of chloride ions is 0.05-0.4 g / L.
[0008] Preferably, the silver removal agent in step (1) is one or a combination of carbon disulfide, methyl xanthate, thioacetaldehyde, thioacetone, phenyl thioyl ylide, and thiourea.
[0009] Preferably, the amount of silver removal agent added in the electrolyte for preparing high-purity copper in step (1) is 0.02-0.1 g / L.
[0010] Preferably, the reaction conditions in step (1) are: at 20-60℃, the reaction is stirred at 300-600 rpm for 2-8 hours.
[0011] Preferably, the conditions for precision filtration in step (2) are: the electrolyte for preparing high-purity copper after reaction is precisely filtered through a 0.22μm microporous membrane.
[0012] Mechanism of the invention: Silver removal agents decompose in copper electrolytes due to chemical instability, generating divalent sulfide ions. This invention regulates the decomposition rate of the silver removal agent by synergistically controlling the reaction temperature, copper electrolyte composition (adjusted by the acid concentration and redox potential of the copper electrolyte), and the composition of the silver removal agent, thereby achieving the slow generation of divalent sulfide ions. Based on the fact that the solubility product of silver sulfide is much lower than that of cuprous sulfide and copper sulfide, and combined with the slow generation of divalent sulfide ions, this invention achieves highly selective and deep precipitation of silver ions in copper electrolytes by divalent sulfide ions.
[0013] The beneficial effects of this invention are: This invention introduces a silver removal agent to deeply remove Ag ions from copper electrolyte, which can then be used as the initial copper electrolyte for electrolysis or electrodeposition, facilitating the preparation of high-purity copper cathodes. Furthermore, this deep silver removal process does not introduce excess impurity ions into the copper electrolyte, offering advantages such as depth and environmental friendliness, along with simple equipment and a streamlined process. Attached Figure Description
[0014] Figure 1 This is a process flow diagram of the process for removing silver from the electrolyte and electrolytic refining HPCu-5N high-purity copper for the preparation of high-purity copper according to the present invention. The dashed box shows the process flow diagram corresponding to the technical solution of the present invention. Detailed Implementation
[0015] To better illustrate the purpose, technical solution, and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.
[0016] Unless otherwise specified, all chemical reagents used in the embodiments and comparative examples of this invention were commercially available analytical grade reagents.
[0017] Example 1 A method for removing silver from an electrolyte used in the preparation of high-purity copper specifically includes the following steps: (1) During the electrolysis process, a copper nitrate solution (with a nitric acid concentration of 15 g / L, a copper ion concentration of 50 g / L, a silver ion concentration of 0.24 mg / L, and a chloride ion concentration of 0.2 g / L) was extracted from the electrolytic cell. Thiourea powder (purity ≥ 99.99%) was added to the extracted copper nitrate solution at a ratio of 0.05 g / L. The mixture was then stirred at 30°C and 300 rpm for 6 hours to obtain a copper nitrate solution containing silver sulfide, cuprous sulfide, and copper sulfide precipitates.
[0018] (2) The copper nitrate solution in the electrolytic cell containing silver sulfide, cuprous sulfide and copper sulfide precipitates is precisely filtered through a 0.22 μm microporous membrane. The resulting filtrate is the electrolyte for preparing high-purity copper after removing silver.
[0019] Example 2 A method for removing silver from an electrolyte used in the preparation of high-purity copper specifically includes the following steps: (1) During the electrolysis process, a copper sulfate solution (with a sulfuric acid concentration of 120 g / L, a copper ion concentration of 60 g / L, a silver ion concentration of 0.18 mg / L, and a chloride ion concentration of 0.4 g / L) was extracted from the electrolytic cell. Thioacetaldehyde (purity ≥ 99.995%) was added to the extracted copper sulfate solution at a ratio of 0.1 g / L. The mixture was then stirred at 400 rpm for 8 hours at 20 °C to obtain a copper sulfate solution containing silver sulfide, cuprous sulfide, and copper sulfide precipitates.
[0020] (2) The copper sulfate solution in the electrolytic cell containing silver sulfide, cuprous sulfide and copper sulfide precipitates is precisely filtered through a 0.22 μm microporous membrane. The resulting filtrate is the electrolyte for preparing high-purity copper after removing silver.
[0021] Example 3 A method for removing silver from an electrolyte used in the preparation of high-purity copper specifically includes the following steps: (1) During the electrolysis process, the copper sulfate solution in the electrolytic cell was extracted (the concentration of sulfuric acid in the copper sulfate solution was 80 g / L, the concentration of copper ions was 60 g / L, the concentration of silver ions was 0.24 mg / L, and the concentration of chloride ions was 0.05 g / L). The silver removal agent (the silver removal agent was prepared by mixing carbon disulfide and methyl xanthate in a mass ratio of 1:1) was added to the extracted copper sulfate solution in the electrolytic cell at a ratio of 0.02 g / L. Then, the reaction was stirred at 500 rpm for 2 h at 60 °C to obtain a copper sulfate solution in the electrolytic cell containing silver sulfide, cuprous sulfide and copper sulfide precipitates.
[0022] (2) The copper sulfate solution in the electrolytic cell containing silver sulfide, cuprous sulfide and copper sulfide precipitates is precisely filtered through a 0.22 μm microporous membrane. The resulting filtrate is the electrolyte for preparing high-purity copper after removing silver.
[0023] Example 4 A method for removing silver from an electrolyte used in the preparation of high-purity copper specifically includes the following steps: (1) During the electrolysis process, a copper sulfate solution (with a sulfuric acid concentration of 100 g / L, a copper ion concentration of 60 g / L, a silver ion concentration of 0.30 mg / L, and a chloride ion concentration of 0.2 g / L) is extracted from the electrolytic cell. The silver removal agent (prepared by mixing phenylthioyl ylide and thioacetone in a mass ratio of 1:1) is added to the extracted copper sulfate solution from the electrolytic cell at a ratio of 0.08 g / L. Then, the reaction is stirred at 600 rpm for 6 hours at 40°C to obtain a copper sulfate solution from the electrolytic cell containing silver sulfide, cuprous sulfide, and copper sulfide precipitates.
[0024] (2) The copper sulfate solution in the electrolytic cell containing silver sulfide, cuprous sulfide and copper sulfide precipitates is precisely filtered through a 0.22 μm microporous membrane. The resulting filtrate is the electrolyte for preparing high-purity copper after removing silver.
[0025] Example 5 A method for removing silver from an electrolyte used in the preparation of high-purity copper specifically includes the following steps: (1) During the electrolysis process, a copper nitrate solution (with a nitric acid concentration of 2 g / L, a copper ion concentration of 50 g / L, a silver ion concentration of 0.17 mg / L, and a chloride ion concentration of 0.2 g / L) was extracted from the electrolytic cell. The silver removal agent (prepared by mixing phenylthioyl ylide and thioacetone in a mass ratio of 1:1) was added to the extracted copper nitrate solution from the electrolytic cell at a ratio of 0.08 g / L. The reaction was then stirred at 40°C and 490 rpm for 6 hours to obtain a copper nitrate solution from the electrolytic cell containing silver sulfide, cuprous sulfide, and copper sulfide precipitates.
[0026] (2) The copper nitrate solution in the electrolytic cell containing silver sulfide, cuprous sulfide and copper sulfide precipitates is precisely filtered through a 0.22 μm microporous membrane. The resulting filtrate is the electrolyte for preparing high-purity copper after removing silver.
[0027] Example 6 A method for removing silver from an electrolyte used in the preparation of high-purity copper specifically includes the following steps: (1) During the electrolysis process, a copper nitrate solution (with a nitric acid concentration of 50 g / L, a copper ion concentration of 50 g / L, a silver ion concentration of 0.18 mg / L, and a chloride ion concentration of 0.2 g / L) is extracted from the electrolytic cell. The silver removal agent (prepared by mixing phenylthioyl ylide and thioacetone in a mass ratio of 1:1) is added to the extracted copper nitrate solution from the electrolytic cell at a ratio of 0.08 g / L. Then, the reaction is stirred at 500 rpm for 6 hours at 40°C to obtain a copper nitrate solution from the electrolytic cell containing silver sulfide, cuprous sulfide, and copper sulfide precipitates.
[0028] (2) The copper nitrate solution in the electrolytic cell containing silver sulfide, cuprous sulfide and copper sulfide precipitates is precisely filtered through a 0.22 μm microporous membrane. The resulting filtrate is the electrolyte for preparing high-purity copper after removing silver.
[0029] Comparative Example 1 A method for removing silver from an electrolyte used in the preparation of high-purity copper specifically includes the following steps: Electrolytic copper powder was added to the copper nitrate electrolyte containing silver impurities at a ratio of 25 g / L. The concentration of nitric acid in the copper nitrate electrolyte was 15 g / L, the concentration of copper ions was 50 g / L, the concentration of silver ions was 0.24 mg / L, and the concentration of chloride ions was 0.2 g / L. The reaction was then carried out at 60°C and 320 rpm for 3 hours with stirring to obtain an electrolyte containing precipitated metallic silver particles. The solution was then precisely filtered through a 0.22 μm microporous membrane, and the resulting filtrate was the silver-free copper nitrate electrolyte.
[0030] Comparative Example 2 A method for removing silver from an electrolyte used in the preparation of high-purity copper specifically includes the following steps: (1) During the electrolysis process, the copper sulfate solution in the electrolytic cell was extracted (the concentration of sulfuric acid in the copper sulfate solution was 100 g / L, the concentration of copper ions was 60 g / L, the concentration of silver ions was 0.30 mg / L, and the concentration of chloride ions was 0.2 g / L). Sodium chloride was added to the extracted copper sulfate solution in the electrolytic cell at a ratio of 0.35 g / L. Then, the mixture was stirred at 40°C and 600 rpm for 6 hours to obtain a copper sulfate solution in the electrolytic cell containing silver chloride precipitate.
[0031] (2) The copper sulfate solution containing silver chloride precipitate in the electrolytic cell is precisely filtered through a 0.22 μm microporous membrane. The resulting filtrate is the electrolyte for preparing high-purity copper after removing silver.
[0032] The preparation of high-purity copper using the silver-removed electrolyte of this invention specifically includes the following steps: The electrolyte used in Example 1 for preparing high-purity copper after silver removal was reintroduced into the copper nitrate solution in the electrolytic cell for the electrolytic production of high-purity copper. The electrolysis parameters were configured as follows: the anode material was copper with a purity of 99.9935%, and the cathode material was TA2 titanium plate. The copper ion concentration in the copper electrolyte was 50 g / L, the nitric acid concentration was 15 g / L, the silver ion concentration was 0.24 mg / L, the chloride ion concentration was 0.2 g / L, and the current density was set at 150 A / m. 2 To optimize the electrolysis effect, thiourea was added as an electrolytic additive at a dosage of 40 g / ton of copper, and gelatin was added at a dosage of 60 g / ton of copper. The distance between the cathode and anode was set at 4 cm, and the entire electrolysis process lasted for 4 days, with the copper electrolyte temperature maintained at 20°C. After electrolysis, a high-purity copper cathode product meeting the HPCu-5N grade of the GB / T 26017-2020 High Purity Copper standard (Table 1) was produced. In this embodiment, by synergistically controlling the reaction temperature, copper electrolyte composition, and silver removal agent composition of the silver removal process, the slow generation of divalent sulfur ions and the deep precipitation of silver ions in the copper electrolyte were achieved. This allowed the silver impurities in the electrolyte to be removed in the form of silver sulfide, cuprous sulfide, and copper sulfide precipitates, achieving the purpose of deep and green removal of silver from the electrolyte used in the preparation of high-purity copper, and improving the purity of the copper product obtained by electrolytic refining.
[0033] The electrolyte used in Example 2 for preparing high-purity copper after silver removal was reintroduced into the copper sulfate solution in the electrolytic cell for the electrolytic production of high-purity copper. The electrolysis parameters were configured as follows: the anode material was copper with a purity of 99.9945%, and the cathode material was 316L stainless steel plate. The copper ion concentration in the electrolyte was 60 g / L, the sulfuric acid concentration was 120 g / L, the silver ion concentration was 0.18 mg / L, the chloride ion concentration was 0.2 g / L, the total chloride ion concentration was 0.4 g / L, and the current density was set to 125 A / m. 2 To optimize the electrolysis effect, thiourea was added as an electrolytic additive at a dosage of 40 g / ton of copper, along with gelatin at a dosage of 20 g / ton of copper. The distance between the cathode and anode was set at 4 cm, and the entire electrolysis process lasted for 5 days, with the copper electrolyte temperature maintained at 60°C. After electrolysis, a high-purity copper cathode product meeting the HPCu-6N grade of the GB / T 26017-2020 High Purity Copper standard (Table 1) was produced. This embodiment, through synergistic control of the reaction temperature, copper electrolyte composition, and silver removal agent composition in the silver removal process, achieves the slow generation of divalent sulfur ions and the deep precipitation of silver ions in the copper electrolyte. This allows silver impurities in the electrolyte to be removed in the form of silver sulfide, cuprous sulfide, and copper sulfide precipitates, achieving the goal of deep and green removal of silver from the electrolyte used in the preparation of high-purity copper, and improving the purity of the copper product obtained from electrolytic refining.
[0034] The electrolyte used in Example 3 for preparing high-purity copper after silver removal was reintroduced into the copper sulfate solution in the electrolytic cell for the electrolytic production of high-purity copper. The electrolysis parameters were configured as follows: the anode material was copper with a purity of 99.9971%, and the cathode material was TA2 titanium plate. The copper ion concentration in the copper electrolyte was 60 g / L, the sulfuric acid concentration was 80 g / L, the silver ion concentration was 0.24 mg / L, the chloride ion concentration was 0.05 g / L, and the current density was set at 120 A / m. 2 To optimize the electrolysis effect, thiourea was added as an electrolytic additive at a dosage of 20 g / ton of copper, and gelatin was added at a dosage of 30 g / ton of copper. The distance between the cathode and anode was set to 4 cm, and the entire electrolysis process lasted for 4 days, with the copper electrolyte temperature maintained at 70°C. After electrolysis, a high-purity copper cathode product meeting the HPCu-5N grade of the GB / T 26017-2020 High Purity Copper standard (Table 1) was produced. In this embodiment, by synergistically controlling the reaction temperature, copper electrolyte composition, and silver removal agent composition of the silver removal process, the slow generation of divalent sulfur ions and the deep precipitation of silver ions in the copper electrolyte were achieved. This allowed the silver impurities in the electrolyte to be removed in the form of silver sulfide, cuprous sulfide, and copper sulfide precipitates, achieving the purpose of deep and green removal of silver from the electrolyte used in the preparation of high-purity copper, and improving the purity of the copper product obtained by electrolytic refining.
[0035] The electrolyte used in Example 4 for preparing high-purity copper after silver removal was reintroduced into the copper sulfate solution in the electrolytic cell for the electrolytic production of high-purity copper. The electrolysis parameters were configured as follows: the anode material was copper with a purity of 99.9939%, and the cathode material was TA2 titanium plate. The copper ion concentration in the copper electrolyte was 60 g / L, the sulfuric acid concentration was 100 g / L, the silver ion concentration was 0.30 mg / L, the chloride ion concentration was 0.2 g / L, and the current density was set at 180 A / m. 2 To optimize the electrolysis effect, thiourea was added as an electrolytic additive at a dosage of 40 g / ton of copper, along with gelatin at a dosage of 90 g / ton of copper. The distance between the cathode and anode was set at 4 cm, and the entire electrolysis process lasted for 4 days, with the copper electrolyte temperature maintained at 60°C. After electrolysis, a high-purity copper cathode product meeting the HPCu-5N grade of the GB / T 26017-2020 High Purity Copper standard (Table 1) was produced. This embodiment, through synergistic control of the reaction temperature, copper electrolyte composition, and silver removal agent composition in the silver removal process, achieves the slow generation of divalent sulfur ions and the deep precipitation of silver ions in the copper electrolyte. This allows silver impurities in the electrolyte to be removed in the form of silver sulfide, cuprous sulfide, and copper sulfide precipitates, achieving the goal of deep and green removal of silver from the electrolyte used in the preparation of high-purity copper, and improving the purity of the copper product obtained from electrolytic refining.
[0036] The electrolyte used in Example 5 for preparing high-purity copper after silver removal was reintroduced into the copper nitrate solution in the electrolytic cell for the electrolytic production of high-purity copper. The electrolysis parameters were configured as follows: the anode material was copper with a purity of 99.9945%, and the cathode material was TA2 titanium plate. The copper ion concentration in the copper electrolyte was 50 g / L, the nitric acid concentration was 2 g / L, the silver ion concentration was 0.17 mg / L, the chloride ion concentration was 0.2 g / L, and the current density was set to 250 A / m. 2 To optimize the electrolysis effect, thiourea was added as an electrolytic additive at a dosage of 30 g / ton of copper, along with gelatin at a dosage of 30 g / ton of copper. The distance between the cathode and anode was set to 4 cm, and the entire electrolysis process lasted for 3 days, with the copper electrolyte temperature maintained at 35°C. After electrolysis, a high-purity copper cathode product meeting the HPCu-5N grade of the GB / T 26017-2020 High Purity Copper standard (Table 1) was produced. In this embodiment, by synergistically controlling the reaction temperature, copper electrolyte composition, and silver removal agent composition of the silver removal process, the slow generation of divalent sulfur ions and the deep precipitation of silver ions in the copper electrolyte were achieved. This allowed the silver impurities in the electrolyte to be removed in the form of silver sulfide, cuprous sulfide, and copper sulfide precipitates, achieving the goal of deep and green removal of silver from the electrolyte used in the preparation of high-purity copper, and improving the purity of the copper product obtained from electrolytic refining.
[0037] The electrolyte used in Example 6 for preparing high-purity copper after silver removal was reintroduced into the copper nitrate solution in the electrolytic cell for the electrolytic production of high-purity copper. The electrolysis parameters were configured as follows: the anode material was copper with a purity of 99.9981%, and the cathode material was TA2 titanium plate. The copper ion concentration in the copper electrolyte was 50 g / L, the nitric acid concentration was 50 g / L, the silver ion concentration was 0.18 mg / L, the chloride ion concentration was 0.2 g / L, and the current density was set to 100 A / m. 2 To optimize the electrolysis effect, thiourea was added as an electrolytic additive at a dosage of 35 g / ton of copper, and gelatin was added at a dosage of 50 g / ton of copper. The distance between the cathode and anode was set at 4 cm, and the entire electrolysis process lasted for 5 days, with the copper electrolyte temperature maintained at 30°C. After electrolysis, a high-purity copper cathode product meeting the HPCu-6N grade of the GB / T 26017-2020 High Purity Copper standard (Table 1) was produced. In this embodiment, by synergistically controlling the reaction temperature, copper electrolyte composition, and silver removal agent composition of the silver removal process, the slow generation of divalent sulfur ions and the deep precipitation of silver ions in the copper electrolyte were achieved. This allowed the silver impurities in the electrolyte to be removed in the form of silver sulfide, cuprous sulfide, and copper sulfide precipitates, achieving the purpose of deep and green removal of silver from the electrolyte used in the preparation of high-purity copper, and improving the purity of the copper product obtained by electrolytic refining.
[0038] The electrolyte used for preparing high-purity copper in Comparative Example 1 (after silver removal) was reintroduced into the copper nitrate solution in the electrolytic cell for the electrolytic production of high-purity copper. The electrolysis parameters were configured as follows: the anode material was copper with a purity of 99.9935%, and the cathode material was TA2 titanium plate. The copper ion concentration in the electrolyte was 50 g / L, the nitric acid concentration was 15 g / L, the silver ion concentration was 0.24 mg / L, the chloride ion concentration was 0.2 g / L, and the current density was set at 150 A / m. 2 To optimize the electrolysis effect, thiourea was added as an electrolytic additive at a dosage of 40 g / ton of copper, along with gelatin at a dosage of 60 g / ton of copper. The distance between the cathode and anode was set at 4 cm, and the entire electrolysis process lasted for 4 days, with the copper electrolyte temperature maintained at 20°C. After electrolysis, a high-purity copper cathode product with a copper content of 99.99957% was produced. However, due to its high Ag content of 3.8 ppm, this high-purity copper cathode product ultimately did not meet the requirements for HPCu-5N grade high-purity copper cathode products in the GB / T26017-2020 High Purity Copper standard (Table 1). This is because the silver generated in this comparative reaction immediately covers the surface of the copper powder, forming a dense silver layer. This silver layer blocks the internal copper from contacting the remaining Ag in the solution. + Contact causes the reaction to stop rapidly; this results in only the surface copper powder participating in the reaction, leaving a large amount of copper powder inside unused, leading to a low silver removal rate.
[0039] The electrolyte used for preparing high-purity copper in Comparative Example 2 (after silver removal) was reintroduced into the copper sulfate solution in the electrolytic cell for the electrolytic production of high-purity copper. The electrolysis parameters were configured as follows: the anode material was copper with a purity of 99.9939%, and the cathode material was TA2 titanium plate. The copper ion concentration in the electrolyte was 60 g / L, the sulfuric acid concentration was 100 g / L, the silver ion concentration was 0.30 mg / L, the chloride ion concentration was 0.2 g / L, and the current density was set at 180 A / m. 2 To optimize the electrolysis effect, thiourea was added as an electrolytic additive at a dosage of 40 g / ton of copper, along with gelatin at a dosage of 90 g / ton of copper. The distance between the cathode and anode was set at 4 cm, and the entire electrolysis process lasted for 4 days, with the copper electrolyte temperature maintained at 60℃. After electrolysis, a high-purity copper cathode product with a copper content of 99.99937% was produced. However, due to its high Ag content of 2.7 ppm, this high-purity copper cathode product ultimately did not meet the requirements for HPCu-5N and HPCu-6N grades of high-purity copper cathode products in the GB / T26017-2020 High Purity Copper standard (Table 1). This is because the silver chloride precipitate generated by sodium chloride in the electrolyte used to prepare high-purity copper consists of colloidal microparticles that are difficult to remove.
[0040] Table 1 Chemical composition of HPCu-5N and HPCu-6N high-purity copper (GB / T 26017-2020 High-purity copper) The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.
Claims
1. A method for removing silver from an electrolyte used in the preparation of high-purity copper, characterized in that, Specifically, the following steps are included: (1) During the electrolysis process, the electrolyte for preparing high-purity copper is extracted from the electrolysis device, the silver removal agent is added to the electrolyte for preparing high-purity copper, and then the reaction is stirred to obtain the electrolyte for preparing high-purity copper after the reaction. (2) The electrolyte for preparing high-purity copper after the reaction is precisely filtered, and the resulting filtrate is the electrolyte for preparing high-purity copper after silver removal.
2. The method for removing silver from the electrolyte for preparing high-purity copper according to claim 1, characterized in that, In step (1), the electrolyte used to prepare high-purity copper is either copper sulfate electrolyte or copper nitrate electrolyte. When copper sulfate electrolyte is used as the electrolyte for preparing high-purity copper, the concentration of sulfuric acid in the electrolyte is 80-120 g / L, the concentration of copper ions is 60 g / L, and the concentration of chloride ions is 0.05-0.4 g / L. When copper nitrate electrolyte is used as the electrolyte for preparing high-purity copper, the concentration of nitric acid in the electrolyte is 2-50 g / L, the concentration of copper ions is 50 g / L, and the concentration of chloride ions is 0.05-0.4 g / L.
3. The method for removing silver from the electrolyte for preparing high-purity copper according to claim 1, characterized in that, The silver removal agent in step (1) is one or more of carbon disulfide, methyl xanthate, thioacetaldehyde, thioacetone, phenyl thioyl ylide, and thiourea.
4. The method for removing silver from the electrolyte for preparing high-purity copper according to claim 1, characterized in that, In step (1), the amount of silver removal agent added to the electrolyte for preparing high-purity copper is 0.02-0.1 g / L.
5. The method for removing silver from the electrolyte for preparing high-purity copper according to claim 1, characterized in that, The conditions for the stirring reaction in step (1) are: stirring at 300-600 rpm for 2-8 hours at 20-60℃.
6. The method for removing silver from the electrolyte for preparing high-purity copper according to claim 1, characterized in that, The conditions for precision filtration in step (2) are as follows: the electrolyte for preparing high-purity copper after reaction is precisely filtered through a 0.22μm microporous membrane.