Method for electrolyzing and preparing HPCu-6N5 high-purity copper based on adsorption silver removal

Abstract

The invention discloses a method for electrolyzing and preparing HPCu-6N5 high-purity copper based on adsorption silver removal, and belongs to the technical field of copper electrolytic refining. According to the technical scheme, an anode is a copper plate, and a cathode is a stainless steel or titanium plate; the electrolyte is copper nitrate electrolyte or copper sulfate electrolyte; the electrolysis temperature is 10-70 DEG C, and the current density is 100-350 A / m < 2 >; wherein the anode copper plate is sleeved with an anode mud bag as a silver ion adsorption material, the mesh number of anode mud bag filter cloth is 100-400, acrylic fibers are used as raw materials, and thioamide functional groups are chemically grafted. According to the technical scheme, the anode mud bag made of the modified acrylic fiber filter cloth is used as an adsorption material, the high-efficiency deep adsorption capacity of thioamide functional groups on the filter cloth on the silver ions in the electrolyte is utilized, online continuous deep removal of the concentration of the silver ions in the electrolyte in the electrolysis process is achieved, it is ensured that the purity of obtained cathode copper meets the requirement of HPCu-6N5 high-purity copper, and the service life of the cathode copper is prolonged. Complex equipment and tedious operation steps are not needed, and industrial application is easy.

Description

Technical Field

[0001] The present invention belongs to the technical field of copper electrolytic refining, and particularly relates to a method for electrolytically preparing HPCu-6N5 high-purity copper based on silver removal by adsorption. Background Art

[0002] High-purity copper (purity ≥ 99.999%) has wide applications in the fields of semiconductor manufacturing, display panel technology, photovoltaic energy conversion, aerospace, etc. due to its excellent electrical conductivity and thermal conductivity. The electrolytic method is a process for preparing high-purity copper (such as grades like HPCu-5N, HPCu-6N, HPCu-6N5, HPCu-7N, etc.) at present. Through the electrochemical reaction during electrolysis, copper ions are reduced and deposited on the cathode to form high-purity copper.

[0003] The existing electrolytic methods often use copper sulfate electrolyte, copper nitrate electrolyte, or an electrolyte system that first electrolyzes with copper sulfate and then with copper nitrate. In these electrolyte systems, the silver content in the cathode high-purity copper produced by electrolysis is often higher than the limit regulations for HPCu-6N high-purity copper, which is a common problem.

[0004] One of the origins of this common problem is the too high concentration of silver ions in the electrolyte. Silver ions (Ag + ⁺) are prone to preferentially discharge and precipitate at the cathode due to their more positive electrode potential than copper ions, resulting in too high silver content in high-purity copper. At present, the silver removal technologies for electrolytes include methods such as copper mesh replacement, silver removal by organic additives, and silver removal by activated carbon, etc., but these methods have problems such as high cost, low efficiency, or complex operation. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for electrolytically preparing HPCu-6N5 high-purity copper based on silver removal by adsorption.

[0006] The purpose of the present invention is achieved as follows: The method for electrolytically preparing HPCu-6N5 high-purity copper based on silver removal by adsorption includes the following processes: The anode is a copper plate, and the cathode is a stainless steel or titanium plate; the electrolyte is a copper nitrate electrolyte or a copper sulfate electrolyte; the electrolysis temperature is 10 - 70 °C, and the current density is 100 - 350 A / m 2 ²; Among them, the anode copper plate is sleeved with an anode slime bag as a silver ion adsorption material. The mesh number of the filter cloth of the anode slime bag is 100 - 400 meshes, and the filter cloth of the anode slime bag is made of acrylic fiber and chemically grafted with thioamide functional groups.

[0007] The technical solution of the present invention has the following advantages compared with the prior art: The technical solution of the present invention uses an anode mud bag made of modified acrylic filter cloth as an adsorption material, and utilizes the high-efficiency and deep adsorption ability of thioamide functional groups on the filter cloth for silver ions in the electrolyte to selectively remove silver ions in the electrolyte, realizing the online continuous and deep removal of silver ion concentration in the electrolyte during the electrolysis process, and finally ensuring that the obtained cathode copper purity meets the requirements of HPCu-6N5 high-purity copper.

[0008] The process conditions selected in the technical solution of the present invention are conducive to the diffusion of Cu 2+ , with high electrolysis efficiency, and make the copper deposit more uniformly and denser. Without complex equipment and cumbersome operation steps, it can effectively remove silver ions in the electrolyte, improve the purity of copper, and is easy to industrialize. The regeneration treatment of the anode mud bag is simple and efficient, and the regenerated anode mud bag can be reused, reducing the production cost. Specific embodiments

[0009] The present invention will be further described below, but it is not limited to the present invention in any way. Any transformation or replacement based on the teachings of the present invention belongs to the protection scope of the present invention.

[0010] The method for electrolytic preparation of HPCu-6N5 high-purity copper based on silver removal by adsorption includes the following processes: The anode is a copper plate, and the cathode is a stainless steel or titanium plate; the electrolyte is a copper nitrate electrolyte or a copper sulfate electrolyte; the electrolysis temperature is 10~70 °C, and the current density is 100~350 A / m 2 ; Among them, the anode copper plate is sleeved with an anode mud bag as a silver ion adsorption material. The mesh number of the filter cloth of the anode mud bag is 100~400 meshes. The filter cloth of the anode mud bag is made of acrylic fiber and chemically grafted with thioamide functional groups.

[0011] The anode mud bag can be regenerated by soaking in a 0.3 mol / L nitric acid solution at 25 °C for 0.5 hours to remove the adsorbed silver ions, and the regenerated anode mud bag can be reused.

[0012] The purity of the anode copper plate is 4N.

[0013] When the cathode is stainless steel, it is 316L stainless steel; when the cathode is a titanium plate, the titanium content is ≥99.5%.

[0014] The copper nitrate electrolyte contains 30~80 g / L of copper ions and 1~50 g / L of nitric acid.

[0015] The copper sulfate electrolyte contains 30~60 g / L of copper ions and 80~140 g / L of sulfuric acid.

[0016] The flow mode of the electrolyte is from top to bottom, and the flow rate is 80~800 ml / min.

[0017] The content of thioamide functional groups on the anode slime bag filter cloth is 3 - 7 mmol / g dry fiber.

[0018] The anode slime bag filter cloth is three - layer.

[0019] The distance between the anode and the cathode is 5 - 10 cm.

[0020] The following additives are added to the electrolyte: thiourea 10 - 40 g / t of cathode copper precipitation, gelatin 20 - 60 g / t of cathode copper precipitation, casein 15 - 30 g / t of cathode copper precipitation.

[0021] The cathode electrolysis cycle of a single electrolysis is 1 - 7 days.

[0022] The number of electrolysis times is 1 - 3 times. When 2 times of electrolysis are required, the anode in the second electrolysis is the cathode copper in the first electrolysis. When 3 times of electrolysis are required, the anode in the third electrolysis is the cathode copper in the second electrolysis, until high - purity copper meeting the HPCu - 6N5 standard is obtained.

[0023] Example 1

[0024] The anode is a copper plate with a purity of 4N, and is sleeved with an anode slime bag made of three - layer filter cloth as a silver - ion adsorption material to selectively adsorb silver ions in the copper electrolyte. The mesh number of the anode slime bag filter cloth is 200 mesh, made of acrylic fiber as raw material, and chemically grafted with thioamide functional groups, with a content of 5 mmol / g dry fiber. The cathode is 316L stainless steel, and the distance between the anode and the cathode is 7 cm.

[0025] The electrolyte is a copper sulfate electrolyte containing 60 g / L of copper ions and 100 g / L of sulfuric acid. Add to the electrolyte: thiourea 20 g / t of cathode copper precipitation, gelatin 30 g / t of cathode copper precipitation, casein 15 g / t of cathode copper precipitation. The flow mode of the electrolyte is from top to bottom, and the flow rate is 800 ml / min. The electrolysis temperature is 40 °C, and the current density is 200 A / m 2 .

[0026] The cathode electrolysis cycle of a single electrolysis is 5 days. The anode slime bag can be regenerated by soaking in a 0.3 mol / L nitric acid solution at 25 °C for 0.5 hours to remove the adsorbed silver ions, and the regenerated anode slime bag can be reused. During the electrolysis process, the silver - ion concentration in the electrolyte can be maintained within the range of 0.03 - 0.05 mg / L fluctuating. The high - purity copper product prepared by one - time electrolysis is detected by GD - MS, and the chemical purity meets the requirements of HPCu - 6N5 high - purity copper, and the main grade of copper reaches 6N7.

[0027] Example 2

[0028] The anode is a copper plate with a purity of 4N, covered with an anode slime bag made of three layers of filter cloth as a silver ion adsorption material, which selectively adsorbs silver ions in the copper electrolyte. The filter cloth of the anode slime bag has a mesh number of 100 meshes, is made of acrylic fiber, and is chemically grafted with a thioamide functional group, with a content of 7 mmol / g of dry fiber. The cathode is a titanium plate with a titanium content of ≥99.5%, and the electrode distance between the anode and the cathode is 5 cm.

[0029] The electrolyte is a copper nitrate electrolyte containing 70 g / L of copper ions and 4 g / L of nitric acid. Add to the electrolyte: 30 g / t of thiourea for depositing cathode copper, 50 g / t of gelatin for depositing cathode copper, and 20 g / t of casein for depositing cathode copper. The flow mode of the electrolyte is from top to bottom, and the flow rate is 80 ml / min. The electrolysis temperature is 35 °C, and the current density is 100 A / m 2 。

[0030] The cathode electrolysis cycle for a single electrolysis is 6 days. The regeneration of the anode slime bag is the same as in Example 1. During the electrolysis process, the silver ion concentration in the electrolyte can be maintained within the range of 0.06 - 0.08 mg / L. The high-purity copper product prepared by one electrolysis is detected by GD-MS, and its chemical purity meets the requirements of HPCu-6N5 high-purity copper, and the main copper grade reaches 6N6.

[0031] Example 3

[0032] The anode is a copper plate with a purity of 4N, covered with an anode slime bag made of three layers of filter cloth as a silver ion adsorption material, which selectively adsorbs silver ions in the copper electrolyte. The filter cloth of the anode slime bag has a mesh number of 400 meshes, is made of acrylic fiber, and is chemically grafted with a thioamide functional group, with a content of 3 mmol / g of dry fiber. The cathode is 316L stainless steel, and the electrode distance between the anode and the cathode is 10 cm.

[0033] The electrolyte is a copper sulfate electrolyte containing 30 g / L of copper ions and 80 g / L of sulfuric acid. Add to the electrolyte: 10 g / t of thiourea for depositing cathode copper, 20 g / t of gelatin for depositing cathode copper, and 30 g / t of casein for depositing cathode copper. The flow mode of the electrolyte is from top to bottom, and the flow rate is 300 ml / min. The electrolysis temperature is 55 °C, and the current density is 350 A / m 2 。

[0034] The cathode electrolysis cycle for a single electrolysis is 3 days. The regeneration of the anode slime bag is the same as in Example 1. During the electrolysis process, the silver ion concentration in the electrolyte can be maintained within the range of 0.04 - 0.06 mg / L. The high-purity copper product prepared by one electrolysis is detected by GD-MS, and its chemical purity meets the requirements of HPCu-6N5 high-purity copper, and the main copper grade reaches 6N7.

[0035] Example 4

[0036] First, Example 1 is executed. Secondly, Example 2 is executed. That is, after two electrolyses, the high-purity copper products prepared by these two electrolyses are detected by GD-MS, and the chemical purity meets the requirements of HPCu-6N5 high-purity copper, and the main copper grade reaches 6N7.

[0037] Example 5

[0038] First, Example 1 is repeatedly executed a total of two times, and finally Example 2 is executed. That is, after three electrolyses, the high-purity copper products prepared by these three electrolyses are detected by GD-MS, and the chemical purity meets the requirements of HPCu-6N5 high-purity copper, and the main copper grade reaches 6N7 and the Ag content is reduced to 0.05 ppm.

Claims

1. A method for preparing HPCu-6N5 high-purity copper by electrolysis based on adsorption and silver removal, characterized in that: Including the following processes: The anode is a copper plate, the cathode is a stainless steel or titanium plate; the electrolyte is copper nitrate electrolyte or copper sulfate electrolyte; the electrolysis temperature is 10~70℃, and the current density is 100~350 A / m 2 ; The anode copper plate is covered with an anode mud bag as a silver ion adsorption material, the mesh number of the anode mud bag filter cloth is 100-400 meshes, the anode mud bag filter cloth is made of acrylic fiber and chemically grafted with thioamide functional groups.

2. The method for preparing high-purity copper by electrolysis according to claim 1, characterized in that: The purity of the anode copper plate is 4N.

3. The method for preparing high-purity copper by electrolysis according to claim 1, characterized in that: When the cathode is made of stainless steel, it is 316L stainless steel; when the cathode is made of titanium plate, the titanium content is ≥99.5%.

4. The method for preparing high-purity copper by electrolysis according to claim 1, characterized in that: The copper nitrate electrolyte contains 30-80 g / L of copper ions and 1-50 g / L of nitric acid.

5. The method for preparing high-purity copper by electrolysis according to claim 1, characterized in that: The copper sulfate electrolyte contains 30-60 g / L of copper ions and 80-140 g / L of sulfuric acid.

6. The method for preparing high-purity copper by electrolysis according to claim 1, characterized in that: The content of thioamide functional groups on the anode mud bag filter cloth is 3-7 mmol / g dry fiber.

7. The method for preparing high-purity copper by electrolysis according to claim 1, characterized in that: The distance between the anode and cathode is 5-10 cm.

8. The method for preparing high-purity copper by electrolysis according to claim 1, characterized in that: The following additives are added to the electrolyte: 10-40 g / t of thiourea to precipitate cathode copper, 20-60 g / t of gelatin to precipitate cathode copper, and 15-30 g / t of casein to precipitate cathode copper.

9. The method for preparing high-purity copper by electrolysis according to claim 1, characterized in that: The cathode electrolysis cycle of the single electrolysis is 1 to 7 days.

10. The method for preparing high-purity copper by electrolysis according to claim 1, characterized in that: The number of electrolysis is 1 to 3 times. When 2 electrolysis is required, the anode of the 2nd electrolysis is the cathode copper of the 1st electrolysis. When 3 electrolysis is required, the anode of the 3rd electrolysis is the cathode copper of the 2nd electrolysis, until high-purity copper meeting the HPCu-6N5 standard is obtained.