Impurity removal agent for deeply removing silver from electrolyte prepared from high-purity copper, application of impurity removal agent and method for deeply removing silver from electrolyte

Abstract

The invention relates to an impurity removal agent for deeply removing silver from an electrolyte prepared from high-purity copper, application of the impurity removal agent and a method for deeply removing silver from the electrolyte, and belongs to the technical field of metallurgical engineering. The impurity removal agent is a copper selenide, a copper telluride or a mixture of the copper selenide and the copper telluride. The silver removal method comprises the following steps: adding the impurity removal agent into the electrolyte according to the ratio of the total molar weight of selenium and tellurium to the molar weight of silver being (1: 1)-(500: 1), reacting for 1-6 hours under the conditions of 25-95 DEG C and 400-800 rpm, standing, and sequentially separating through filter cloth (20-38 microns) and a fine filter (0.1-10 microns) to obtain a purified solution. According to the method, the silver content of the electrolyte can be deeply removed to 0.01 mg / L or below, new metal impurities are not introduced, the process is simple and efficient, and the method is suitable for industrial purification production of a copper sulfate or copper nitrate system.

Description

Technical Field

[0001] This application relates to the field of metallurgical engineering technology, and in particular to a descaling agent for deep silver removal from electrolytes prepared from high-purity copper, its application, and a method for deep silver removal from electrolytes. Background Technology

[0002] With the rapid development of modern technology in fields such as semiconductors, optoelectronics, and new energy, high-purity copper has become a key material due to its excellent electrical conductivity, thermal conductivity, and chemical stability. Currently, high-purity copper is mainly produced through electrolytic refining or electrolytic deposition processes. However, the control of impurity elements is particularly critical during the electrolysis process. In particular, metallic impurities that are more positively charged than copper (such as silver) are difficult to completely remove, becoming a major bottleneck restricting the purity of the product.

[0003] During electrolysis, elements with a significantly negative deposition potential than copper enter the electrolyte instead of depositing at the cathode during anode dissolution. While more positively charged elements should theoretically form anode slime, impurities in the anode often exist as multi-element alloy phases, and some positively charged impurities may still dissolve and enter the electrolyte, ultimately depositing at the cathode and affecting copper purity. Furthermore, the introduction of fresh electrolyte during electrolytic deposition can also introduce trace amounts of positively charged impurities, further exacerbating cathode contamination. Therefore, efficiently removing positively charged metallic impurities, especially silver, from the electrolyte has become a crucial challenge in the preparation of high-purity copper.

[0004] Developing a new method for purifying and removing silver from copper electrolyte that is easy to operate, has good purification effect, does not introduce new impurities, and can effectively recover valuable metals such as silver has always been the pursuit of those skilled in the art. Summary of the Invention

[0005] To address or partially address the problems existing in related technologies, this application provides a descaling agent for deep silver removal from electrolytes prepared from high-purity copper, its application, and a method for deep silver removal from electrolytes, which can achieve deep purification of silver without introducing other new metallic impurities.

[0006] The impurity removal agent for deep silver removal from electrolytes prepared from high-purity copper, as described in this application, is composed of any of the following components: (a) A copper selenide, wherein the copper selenide is one or both of copper selenide and cuprous selenide. (b) A copper telluride, wherein the copper telluride is one or both of copper telluride and cuprous telluride; (c) A mixture of copper selenide and copper telluride, wherein the copper selenide is one or both of copper selenide and cuprous selenide, and the copper telluride is one or both of copper telluride and cuprous telluride.

[0007] This application also provides the application of the above-described impurity remover in the deep silver removal of electrolytes used in the preparation of high-purity copper.

[0008] This application also provides a method for deep silver removal from an electrolyte, comprising the following steps: (1) Add the above-mentioned impurity removal agent to the electrolyte for deep silver removal; wherein the amount of the impurity removal agent added satisfies the following: the total molar ratio of selenium and tellurium in the impurity removal agent to the total molar ratio of silver in the electrolyte is 1:1-500:1. (2) The impurity removal reaction was carried out under the set temperature and stirring conditions. After the reaction was completed, stirring was stopped and the mixture was allowed to settle to obtain the impurity-removed slurry. (3) The impurity-removing slurry is passed through a filter cloth filter and a fine filter in sequence to separate the deeply purified liquid and the electrolyte desilvering slag.

[0009] Furthermore, in step (2), the temperature is 25-95℃, the stirring speed is 400-800 rpm, the reaction time is 1-6h, and the settling time is 1-6h.

[0010] Furthermore, in step (3), the filter cloth is 400-500 mesh, the filtration accuracy is 20μm-38μm, and the filter cloth material is polyethylene or polypropylene.

[0011] Furthermore, the filtration accuracy of the fine filter in step (3) is 0.1μm - 10μm.

[0012] Furthermore, the fine filter may be a single-stage or multi-stage filter.

[0013] Furthermore, the initial silver content in the electrolyte to be deeply desilvered is 0.01-500 ppm.

[0014] Furthermore, the electrolyte for deep silver removal is any one of the following: (1) Electrolyte of copper nitrate-nitric acid system used for the preparation of high-purity copper, or the concentrated solution of the electrolyte of the system after evaporation; (2) Copper sulfate-sulfuric acid system electrolyte used for the preparation of high-purity copper, or the crystallization mother liquor after the electrolyte of the system has been treated by the "evaporation concentration-cooling crystallization" process.

[0015] The silver removal mechanism of the impurity remover in this application is as follows: In copper telluride, cuprous telluride, copper selenide, and cuprous selenide, the copper electrode potential is more negative than that of silver. Furthermore, because copper forms intermetallic compounds with tellurium and selenium, its electrode potential becomes even more negative, making it easier to displace silver from the solution. Simultaneously, the displaced silver readily forms highly inert silver-selenium-telluride intermetallic compounds with selenium and tellurium, thereby reducing secondary acid etching and dissolution of the displaced silver by the electrolyte.

[0016] The beneficial effects of this application are: 1. The impurity remover in this application can remove silver content in the electrolyte to below 0.01 mg / L, achieving deep purification of the electrolyte. Moreover, the impurity remover itself will not introduce new metal impurities, thus ensuring the purity of the electrolyte.

[0017] 2. The purification method of the impurity removal agent in this application is simple in process and easy to operate, and has the advantages of high impurity removal efficiency and stable effect, and is suitable for industrial production. Detailed Implementation

[0018] The embodiments of this application will now be described in more detail with reference to the examples. While embodiments of this application are shown in the examples, it should be understood that this application can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to make this application more thorough and complete, and to fully convey the scope of this application to those skilled in the art. Example 1

[0019] This embodiment provides a method for deep silver removal from high-purity copper electrolyte, specifically including the following steps: (1) First, the silver content of the copper sulfate-sulfuric acid system electrolyte to be purified was tested and analyzed. Then, 120L of the electrolyte to be purified was injected into the purification tank. The mass concentration of silver in this batch of electrolyte was 3.90 mg / L. Based on this, the total mass of silver in the electrolyte was calculated to be 468 mg (calculation basis: 120L×3.90 mg / L=468 mg), and the total molar mass of silver was 4.32 mmol (calculation basis: 468 mg÷107.87 g / mol≈4.32 mmol, and the molar mass of silver is calculated as 107.87 g / mol).

[0020] (2) Addition of impurity removal agent and purification reaction In this embodiment, the amount of the impurity remover is determined by the ratio of "the total molar amount of selenium (Se) and tellurium (Te) in the impurity remover to the total molar amount of silver (Ag) in the electrolyte is 500:1", wherein the cuprous selenide (Cu2Se) and cuprous telluride (Cu2Te) in the impurity remover are mixed in a mass ratio of 4:1.

[0021] Add the calculated amount of descaling agent to a purification tank containing 120L of electrolyte to be purified. Turn on the stirrer to ensure that the descaling agent and electrolyte are fully mixed. Control the reaction conditions as follows: reaction temperature 45℃, stirring speed 500 rpm, constant temperature reaction time 3h. After the reaction is completed, stop stirring and let stand for 3h to allow the reaction products to settle completely.

[0022] (3) Solid-liquid separation and purification effect detection After settling, the mixture (including the silver removal slag) in the purification tank is completely exported and sequentially passed through a two-stage filtration system for solid-liquid separation: the first stage is a 400-mesh (filtration accuracy approximately 38μm) polypropylene filter cloth, and the second stage is a fine filter with a filtration accuracy of 10μm. The purified electrolyte and solid silver removal slag are obtained through filtration and separation.

[0023] The purified solution was tested for silver content, and the results showed that its silver concentration had decreased to 0.004 mg / L. This purified solution was used in a high-purity copper electrolytic preparation process, and the final high-purity copper product achieved a main grade of 99.999991%, with a silver content of 0.005 ppm. The contents of other impurity elements and all performance indicators met the technical requirements for the HPCu-6N5 grade in the national standard GB / T 26017-2020. Example 2

[0024] This embodiment provides a method for deep silver removal from high-purity copper electrolyte, specifically including the following steps: (1) First, the mother liquor of the copper sulfate-sulfuric acid system electrolyte used for the preparation of high-purity copper was taken as the electrolyte to be purified after being treated by "evaporation concentration-cooling crystallization". The silver content of the electrolyte was then tested. Then, 100L of the electrolyte to be purified was injected into the purification tank. The test showed that the mass concentration of silver in this batch of electrolyte was 4.7mg / L. Based on this, the total mass of silver in the electrolyte was calculated to be 470mg (calculation basis: 100L×4.7mg / L=470mg), and the total molar mass of silver was 4.36mmol (calculation basis: 470mg÷107.87g / mol≈4.36mmol, and the molar mass of silver is calculated as 107.87g / mol).

[0025] (2) Addition of impurity removal agent and purification reaction In this embodiment, the amount of the impurity remover is determined according to the ratio of "the total molar ratio of selenium (Se) and tellurium (Te) in the impurity remover to the total molar ratio of silver (Ag) in the electrolyte is 10:1". The impurity remover is made of copper selenide (CuSe) and copper telluride (CuTe) in a mass ratio of 10:1.

[0026] Add the calculated amount of descaling agent to a purification tank containing 100L of electrolyte to be purified. Turn on the stirrer to ensure that the descaling agent and electrolyte are fully mixed. Control the reaction conditions as follows: reaction temperature 30℃, stirring speed 600 rpm, constant temperature reaction time 6h. After the reaction is completed, stop stirring and let stand for 3h to allow the reaction products to settle completely.

[0027] (3) Solid-liquid separation and purification effect detection After settling, the mixture (including the silver removal slag) in the purification tank is completely exported and sequentially passed through a two-stage filtration system for solid-liquid separation: the first stage is a 500-mesh (20μm filtration accuracy) polypropylene filter cloth, and the second stage is a two-stage series fine filter (first stage filtration accuracy 10.0μm, second stage filtration accuracy 5.0μm). The purified electrolyte and solid silver removal slag are obtained through filtration and separation.

[0028] The purified solution was tested for silver content, and the results showed that its silver concentration had decreased to 0.002 mg / L. This purified solution was used in a high-purity copper electrolytic production process, and the final high-purity copper product achieved a main grade of 99.999989% (7N grade), with a silver content of 0.007 ppm. The contents of other impurity elements and all performance indicators met the technical requirements of the HPCu-6N5 grade in the national standard GB / T26017-2020. Example 3

[0029] This embodiment provides a method for deep silver removal from high-purity copper electrolyte, specifically including the following steps: (1) First, the mother liquor of the copper sulfate-sulfuric acid system electrolyte used for the preparation of high-purity copper after "evaporation concentration-cooling crystallization" was taken as the electrolyte to be purified and the silver content was tested. Then, 200L of the electrolyte to be purified was injected into the purification tank. The mass concentration of silver in this batch of electrolyte was 0.056 mg / L. Based on this, the total mass of silver in the electrolyte was calculated to be 11.2 mg (calculation basis: 200L×0.056 mg / L=11.2 mg), and the total molar mass of silver was 0.104 mmol (calculation basis: 11.2 mg÷107.87 g / mol≈0.104 mmol, and the molar mass of silver is calculated as 107.87 g / mol).

[0030] (2) Addition of impurity removal agent and purification reaction In this embodiment, the amount of the impurity remover is determined according to the ratio of "the molar amount of tellurium (Te) in the impurity remover (since it only contains cuprous telluride, the total molar amount of selenium and tellurium is the molar amount of tellurium) to the total molar amount of silver (Ag) in the electrolyte is 150:1", wherein the impurity remover is composed of a single component, cuprous telluride (Cu2Te).

[0031] The calculated amount of cuprous telluride impurity remover was added to a purification tank containing 200L of electrolyte to be purified. Stirring was started to ensure that the impurity remover and electrolyte were fully mixed. The reaction conditions were controlled as follows: reaction temperature 50℃, stirring speed 500 rpm, constant temperature reaction time 5h. After the reaction was completed, stirring was stopped and the mixture was allowed to stand for 1h to allow the reaction products to settle completely.

[0032] (3) Solid-liquid separation and purification effect detection After settling, the mixture (including the silver removal slag) in the purification tank is completely exported and sequentially passed through a two-stage filtration system for solid-liquid separation: the first stage is a 400-mesh (38μm filtration accuracy) polypropylene filter cloth, and the second stage is a two-stage series fine filter (first stage filtration accuracy 10.0μm, second stage filtration accuracy 1.0μm). The purified liquid and solid silver removal slag are obtained through filtration and separation.

[0033] The purified solution was tested for silver content, and the results showed that its silver concentration had decreased to 0.002 mg / L. This purified solution was used in a high-purity copper electrolytic production process, and the final high-purity copper product achieved a main grade of 99.999985% (7N grade), with a silver content of 0.003 ppm. The content of other impurity elements and all performance indicators met the technical requirements of the HPCu-6N5 grade in the national standard GB / T26017-2020. Example 4

[0034] This embodiment provides a method for deep silver removal from high-purity copper electrolyte, and the specific operation steps are as follows: (1) First, the silver content of the electrolyte to be purified in the copper nitrate-nitric acid system used in the preparation of high-purity copper was tested, and then 150L of the electrolyte was injected into the purification tank. The test showed that the silver content in this batch of electrolyte was 1.6mg / L. Based on this volume, the total mass of silver in the electrolyte was 240mg (150L×1.6mg / L), which corresponds to a total molar amount of silver of 2.23mmol.

[0035] (2) Addition of impurity removal agent and purification reaction In this embodiment, the amount of the impurity remover is determined according to the ratio of "the total molar ratio of selenium (Se) and tellurium (Te) in the impurity remover to the total molar ratio of silver (Ag) in the electrolyte is 20:1". The impurity remover is composed of copper selenide (Cu2Se) and copper telluride (Cu2Te) in a mass ratio of 4:1.

[0036] The calculated amount of impurity remover was added to the electrolyte in the purification tank and mixed thoroughly. The reaction conditions were controlled as follows: reaction temperature 25℃, stirring speed 600rpm, reaction time 6h, and after the reaction, the mixture was allowed to stand for 6h to complete the electrolyte purification process.

[0037] (3) Solid-liquid separation and purification effect detection After the purification process is completed, the mixture (including silver removal slag) in the purification tank is exported as a whole and passed through a 500-mesh (corresponding to a filtration accuracy of about 25μm) and a filtration accuracy of 20μm polypropylene filter cloth in sequence. Then, it is filtered step by step through a three-stage fine filter with filtration accuracies of 10.0μm, 5.0μm and 1.0μm respectively, and finally the purified liquid and the silver removal slag of the electrolyte are separated.

[0038] Test results showed that the silver content in the purified solution decreased to 0.001 mg / L. When this purified solution was used in a high-purity copper preparation process, the resulting high-purity copper had a main grade of 99.999993%, with a silver content of 0.006 ppm. The contents of other impurity elements all met the technical requirements for the HPCu-6N5 grade in the national standard GB / T 26017-2020. Example 5

[0039] This embodiment provides a method for deep silver removal from high-purity copper electrolyte, and the specific operation steps are as follows: (1) First, the silver content of the copper sulfate-sulfuric acid system electrolyte to be purified, which was treated by the "evaporation concentration-cooling crystallization" process and used in the preparation of high-purity copper, was tested. Then, 250L of the electrolyte was injected into the purification tank. The test showed that the silver content of this batch of electrolyte was 0.075mg / L, and the total mass of silver by volume was 18.75mg (250L×0.075mg / L), corresponding to a total molar amount of silver of 0.174mmol.

[0040] (2) Addition of impurity removal agent and purification reaction The amount of the impurity remover is determined according to the ratio of "total molar amount of selenium (Se) and tellurium (Te) in the impurity remover to total molar amount of silver (Ag) in the electrolyte 200:1". The impurity remover is made by mixing cuprous selenide (Cu2Se) and cuprous telluride (Cu2Te) in a mass ratio of 8:1.

[0041] The calculated amount of impurity remover was added to the purification tank and mixed thoroughly with the electrolyte. The purification reaction conditions were controlled as follows: reaction temperature 35℃, stirring speed 600rpm, reaction time 4h, and the mixture was allowed to stand for 2h after the reaction to complete the purification.

[0042] (3) Solid-liquid separation and purification effect detection After purification, the mixture (including silver removal slag) in the purification tank is exported as a whole and passed through a 500-mesh (corresponding to a filtration accuracy of about 25μm) and a filtration accuracy of 20μm polypropylene filter cloth in sequence. Then it is filtered through a two-stage fine filter with filtration accuracies of 10.0μm and 5.0μm respectively, and finally the purified liquid and the silver removal slag of the electrolyte are separated.

[0043] Test results showed that the silver content in the purified solution decreased to 0.004 mg / L. This purified solution was used for the preparation of high-purity copper, yielding copper with a main grade of 99.999990%, a silver content of 0.005 ppm, and the contents of other impurity elements all met the technical requirements for the HPCu-6N5 grade in the national standard GB / T 26017-2020. Example 6

[0044] This embodiment provides a method for deep silver removal from high-purity copper electrolyte, specifically including the following steps: (1) First, the mother liquor of the copper sulfate-sulfuric acid system electrolyte used for the preparation of high-purity copper after "evaporation concentration-cooling crystallization" was taken as the electrolyte to be purified and the silver content was tested. Then, 200L of the electrolyte to be purified was injected into the purification tank. The silver concentration in this batch of electrolyte was 0.056 mg / L. Based on this, the total mass of silver in the electrolyte was calculated to be 11.2 mg (calculation basis: 200L×0.056 mg / L=11.2 mg), and the total molar mass of silver was 0.104 mmol (calculation basis: 11.2 mg÷107.87 g / mol≈0.104 mmol, and the molar mass of silver is calculated as 107.87 g / mol).

[0045] (2) Addition of impurity removal agent and purification reaction The amount of the impurity remover is determined according to the ratio of "total molar amount of selenium (Se) and tellurium (Te) in the impurity remover to total molar amount of silver (Ag) in the electrolyte of 1:1". The impurity remover is made by mixing cuprous selenide (Cu2Se) and cuprous telluride (Cu2Te) in a mass ratio of 8:1.

[0046] Add the calculated amount of impurity remover to a purification tank containing 200L of electrolyte to be purified. Turn on the stirrer to ensure that the impurity remover and electrolyte are fully mixed. Control the reaction conditions as follows: reaction temperature 50℃, stirring speed 500 rpm, constant temperature reaction time 5h. After the reaction is completed, stop stirring and let stand for 1h to allow the reaction products to settle completely.

[0047] (3) Solid-liquid separation and purification effect detection After settling, the mixture (including the silver removal slag) in the purification tank is completely exported and sequentially passed through a two-stage filtration system for solid-liquid separation: the first stage is a 400-mesh (38μm filtration accuracy) polypropylene filter cloth, and the second stage is a two-stage series fine filter (first stage filtration accuracy 10.0μm, second stage filtration accuracy 1.0μm). The purified liquid and solid silver removal slag are obtained through filtration and separation.

[0048] The purified solution was tested for silver content, and the results showed that its silver concentration had decreased to 0.008 mg / L. This purified solution was used in a high-purity copper electrolytic preparation process, and the final high-purity copper product achieved a main grade of 99.9995% (5N grade), with a silver content of 0.01 ppm. The content of other impurity elements and all performance indicators met the technical requirements of the HPCu-5N grade in the national standard GB / T 26017-2020.

[0049] The various embodiments of this application 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 depurifying agent for deep silver removal from electrolytes prepared from high-purity copper, characterized in that: The impurity removal agent is composed of any of the following components: (a) A copper selenide, wherein the copper selenide is one or both of copper selenide and cuprous selenide. (b) A copper telluride, wherein the copper telluride is one or both of copper telluride and cuprous telluride; (c) A mixture of copper selenide and copper telluride, wherein the copper selenide is one or both of copper selenide and cuprous selenide, and the copper telluride is one or both of copper telluride and cuprous telluride.

2. The application of the impurity remover according to claim 1 in the deep silver removal of electrolyte in the preparation of high-purity copper.

3. A method for deep silver removal using an electrolyte, characterized in that: Includes the following steps: (1) Add the impurity remover of claim 1 to the electrolyte for deep silver removal; wherein the amount of the impurity remover added satisfies the following: the total molar ratio of selenium and tellurium in the impurity remover is 1:1-500:1 to the total molar ratio of silver in the electrolyte; (2) The impurity removal reaction was carried out under the set temperature and stirring conditions. After the reaction was completed, stirring was stopped and the mixture was allowed to settle to obtain the impurity-removed slurry. (3) The impurity-removing slurry is passed through a filter cloth filter and a fine filter in sequence to separate the deeply purified liquid and the electrolyte desilvering slag.

4. The method according to claim 3, characterized in that, The temperature in step (2) is 25-95℃, the stirring speed is 400-800 rpm, the reaction time is 1-6h, and the settling time is 1-6h.

5. The method according to claim 3, characterized in that, The filter cloth in step (3) has a mesh size of 400-500, a filtration accuracy of 20μm-38μm, and is made of polyethylene or polypropylene.

6. The method according to claim 3, characterized in that, The fine filter in step (3) has a filtration accuracy of 0.1μm - 10μm.

7. The method according to claim 6, characterized in that, The fine filter may be a single-stage or multi-stage filter.

8. The method according to claim 3, characterized in that, The initial silver content in the electrolyte to be used for deep silver removal is 0.01-500 ppm.

9. The method according to any one of claims 3-8, characterized in that, The electrolyte for deep silver removal is any one of the following: (1) Electrolyte of copper nitrate-nitric acid system used for the preparation of high-purity copper, or the concentrated solution of the electrolyte of the system after evaporation; (2) The copper sulfate-sulfuric acid system electrolyte used for the preparation of high-purity copper, or the crystallization mother liquor after the electrolyte of the system has been treated by the "evaporation concentration-cooling crystallization" process.