Method for preparing high-purity copper through magnetized electrolyte assisted electrolysis

Abstract

The invention belongs to the technical field of metal purification and preparation, and particularly relates to a method for preparing high-purity copper through magnetized electrolyte assisted electrolysis. The method comprises the following steps: 1) obtaining a copper salt solution as an electrolyte; 2) removing impurities from the electrolyte obtained in the step 1); (3) magnetizing the electrolyte subjected to impurity removal; and (4) the magnetized electrolyte obtained in the step (3) is placed in an electrolysis device to be electrolyzed, pure copper with the purity larger than or equal to 99.9% is obtained on a cathode, in the electrolysis device, the pure copper with the purity larger than or equal to 99% is used as an anode material, and a carbon plate, a stainless steel plate or a pure titanium plate is used as a cathode material. According to the invention, the electrolyte is magnetized in a uniform magnetic field, and the magnetized electrolyte is electrolyzed. And in the electrolysis process, the deposition rate of electrolytic copper on the cathode plate is increased, the energy consumption in the electrolysis process is reduced, meanwhile, the product is densely and uniformly separated out, and the stability is improved.

Description

Technical Field

[0001] This invention belongs to the field of metal purification and preparation technology, specifically relating to a method for preparing high-purity copper by electrolysis assisted by a magnetized electrolyte. Background Technology

[0002] High-purity copper, as an excellent material, demonstrates significant application value in aerospace, electronics, military industry, and new energy fields due to its superior corrosion resistance, fatigue resistance, and electrical and thermal conductivity, and has become a key development direction in the field of new materials. Currently, pure copper preparation mainly includes electrolytic refining, vacuum melting, and zone melting. Among these, electrolysis, due to its low cost, short process, and ease of operation, has become the core technology for achieving high-purity and even ultra-pure copper. In terms of application scenarios, electrolytic copper is not only used in the power sector, such as in power cables, transformers, and reactors, but also widely applied in transportation and machinery manufacturing. Given the high cost of traditional electrolysis methods using industrial pure copper as raw material, the preparation of high-purity copper using low-cost anode materials has become an important research and development direction for the industry under the current trend of mass production.

[0003] In current industrial production, the electrolytic refining of high-purity copper typically uses crude copper (99.5%-99.9% purity, mostly a product of pyrometallurgical processes) as the anode, and the electrolyte is mainly a mixture of copper sulfate (CuSO4) and sulfuric acid (H2SO4). However, traditional processes have significant technical bottlenecks: on the one hand, during electrolysis, copper ions (CuSO4)... 2+ The electrodeposition rate is limited by the current density (typically 150-250 A / m). 2 ) and electrolyte diffusion efficiency, Cu per unit time 2+ The reduction and deposition efficiency at the cathode (pure copper starting sheet) is low, resulting in a production cycle of 7-10 days for high-purity copper (5N grade and above), which is difficult to meet the demand for large-scale supply in high-end fields. On the other hand, traditional processes lack efficient electrolyte purification and circulation mechanisms, and Fe... 2+ Ni 2+ The continuous accumulation of impurity ions in the electrolyte necessitates frequent discharge and treatment, resulting in a waste of copper sulfate and sulfuric acid resources. Furthermore, the overall energy consumption of the system reaches 200-300 kWh / ton of copper, significantly reducing resource utilization and economic efficiency. This invention provides a method for preparing high-purity copper by magnetic field pretreatment and magnetized electrolyte-assisted electrolysis. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a method for preparing high-purity copper using a magnetized electrolyte-assisted electrolysis. This invention magnetizes the electrolyte under a uniform magnetic field and then electrolyzes the magnetized electrolyte. During electrolysis, the deposition rate of electrolytic copper on the cathode plate is accelerated, the energy consumption of the electrolysis process is reduced, and the product exhibits dense and uniform precipitation with improved stability.

[0005] The technical solution provided by this invention is as follows: A method for preparing high-purity copper by electrolysis assisted by a magnetized electrolyte includes the following steps: 1) Obtain a copper salt solution to use as an electrolyte; 2) Remove impurities from the electrolyte obtained in step 1); 3) Magnetize the purified electrolyte; 4) The magnetized electrolyte obtained in step 3) is placed in an electrolysis device for electrolysis to obtain pure copper with a purity greater than or equal to 99.9% at the cathode. In the electrolysis device, the anode material is pure copper with a purity greater than or equal to 99%, and the cathode material is a carbon plate, a stainless steel plate, or a pure titanium plate.

[0006] Specifically, in step 1): The copper salt is copper sulfate or copper nitrate, preferably copper sulfate pentahydrate or copper nitrate trihydrate, and more preferably copper sulfate pentahydrate. The concentration of the copper sulfate salt is 0.005-0.015 mol / L, preferably 0.01 mol / L.

[0007] Specifically, in step 1): acid is added to adjust the pH to 2-4, preferably to 3.

[0008] Based on the above technical solutions, side reactions such as hydrogen evolution reaction can be reduced.

[0009] Furthermore, in step 2): firstly, chelating resin is used to remove metallic impurities, including Co, Ni, Fe, etc.; then, strong basic anion exchange resin and boric acid-specific resin are used to remove non-metallic impurities, including P, Si, B, etc.; after impurity removal, the sum of the contents of Co, Ni, Fe and Zn elements is not higher than 50 ppm.

[0010] Based on the above technical solution, the electrolyte is made purer, and the deposition of impurities along with copper ions on the cathode plate is further avoided during the subsequent electrolytic preparation of copper.

[0011] Specifically, in step 3): a uniform and stable magnetic field is applied to the electrolyte in a strong magnetic field device. The magnitude of the magnetic field is greater than 0 and less than or equal to 1000 mT. Preferably, it is 400 mT or 800 mT. The magnetization time is 20-30 min, preferably 30 min, to magnetize the electrolyte.

[0012] The CFM-12T-150-H3 can be used to provide a steady-state strong magnetic field.

[0013] Specifically, in step 4): the electrolysis device is placed in a constant temperature water bath for electrolysis, with a temperature of 25-30℃, preferably 25℃.

[0014] Specifically, in step 4): the current density of the cathode plate is 490-510 A / m. 2 Preferably, it is 500 A / m 2 .

[0015] Specifically, in step 4), the electrolysis time is 1-3 hours, preferably 2 hours.

[0016] Specifically, in step 4): the distance between the anode and cathode of the electrolysis device is constant.

[0017] Specifically, in step 4): compared to using an unmagnetized electrolyte, the energy consumption for electrolytic copper is reduced.

[0018] The obtained electrolytic copper is weighed after separation, washing, and drying, and then packaged in a vacuum or with inert gases such as argon or nitrogen to avoid any possible trace amounts of active sites that may react with O2 in the air to form oxide layers such as Cu2O and CuO. This ensures the purity and physicochemical stability of the electrolytic copper, while extending its shelf life and preventing secondary contamination.

[0019] The present invention has the following beneficial effects: Using ion exchange resin to perform ion exchange on the electrolyte can effectively remove copper-like elements such as Co, Ni, and Fe, as well as non-metallic impurities such as B and P, significantly improving the purity of the electrolyte and preventing impurities from depositing on the cathode plate during electrolysis. In terms of production efficiency optimization, pre-magnetizing the electrolyte changes the aggregation and migration characteristics of copper ions in the solution, enhances ion diffusion ability, provides more reactants for the electrolysis reaction, significantly accelerates the deposition rate of copper on the cathode, significantly shortens the overall electrolysis time, effectively increases the yield of high-purity copper per unit time, and the product is dense and uniformly precipitated with improved stability. From the perspective of reducing electrolysis energy consumption, the magnetic field weakens the hydrogen bond association of water molecules, reduces the size and radius of hydrated ion clusters, and enhances Cu... 2+ The diffusion coefficient and resistivity are reduced, the overpotential is decreased, the power loss is reduced, the energy cost of high-purity copper preparation is reduced, and the production cost is effectively controlled. Attached Figure Description

[0020] Figure 1 This is a graph showing the changes in electrodeposition rate in comparative embodiments 1, 2, and 3 of the present invention.

[0021] Figure 2 The graph shows the changes in electrolysis energy consumption in comparative embodiments 1, 2, and 3 of the present invention.

[0022] Figure 3 The images show the detection results of the cathode electrolytic copper morphology in comparative embodiments 1, 2, and 3 of this invention. Detailed Implementation

[0023] The principles and features of the present invention are described below. The embodiments given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0024] Unless otherwise specified, the test methods used in the embodiments are conventional methods; unless otherwise specified, the materials and reagents used are commercially available.

[0025] The strong magnetic field equipment is from Dongfang Chenjing, and the model is CFM-12T-150-H3.

[0026] The brand names and models of the chelating resins are Amberlite IRC748 and Lewatit TP 207.

[0027] The brand and model of the strong basic anion exchange resin is Amberlite IRA402.

[0028] The brand and model of the boric acid-specific resin is Amberlite IRA 743.

[0029] Example 1 A method for preparing high-purity copper by electrolysis assisted by a magnetized electrolyte specifically includes the following steps: Step A: Prepare an electrolyte solution using copper sulfate pentahydrate (CuSO4·5H2O) as the raw material. The concentration of the prepared electrolyte solution is 0.01 mol / L. Adjust the pH of the electrolyte solution by adding dilute sulfuric acid using a pH meter. The concentration of the dilute sulfuric acid used is 1 mol / L. The target pH is 3. Too low a pH will aggravate hydrogen evolution. A pH of around 3 is more suitable. Step B involves using an ion exchange resin to perform ion exchange on the solution after pH adjustment in Step A. The ion exchange process involves first using a chelating resin to preferentially remove metallic impurities such as Co, Ni, and Fe, and then using a strong basic anion exchange resin and a boric acid-specific resin to remove non-metallic impurities such as P, Si, and B. After ion exchange, the impurity elements in the solution are significantly reduced. Specifically, the sum of the contents of Co, Ni, Fe, and Zn elements should not exceed 50 ppm, making the electrolyte purer and further preventing the deposition of copper ions on the cathode plate during the subsequent electrolytic preparation of copper. Step C: The electrolyte treated with the ion exchange resin is placed in a strong magnetic field device. The strong magnetic field device uses a CFM-12T-150-H3 steady-state strong magnetic field to apply a uniform and stable magnetic field to the electrolyte for a certain period of time. The magnetic field strength is 400 mT and the magnetization time is 30 min (excluding the time to increase the magnetic field strength to the target magnetic field strength) to magnetize the electrolyte. Step D: Use a pure copper plate as the anode (size 100*100*2mm) 3 The area used for electrolysis is greater than 40 cm².2 The cathode is a pure titanium plate (100*100*2mm). 3 The area where electrolysis takes place is 40 cm². 2 Simultaneously, the magnetized electrolyte is placed in an electrolytic cell for electrolysis. To maintain consistent electrolysis conditions, the electrolytic cell is placed in a constant-temperature water bath at 25°C, and the cathode current density is 500 A / m. 2 To avoid the electrolyte being oxidized and contaminated under natural conditions due to prolonged electrolysis, the electrolysis time is controlled to 2 hours, and copper powder is obtained after electrolysis.

[0030] Before electrolysis, the surfaces of the anode and cathode plates are acid-washed to remove rust, ground, polished, and impurities are removed. They are then rinsed thoroughly with deionized water to ensure the plates themselves do not contaminate the electrolyte. During electrolysis, to avoid interference from other factors, the distance between the anode and cathode plates remains constant, except for the current density and electrolysis temperature. After electrolysis, the electrical energy consumed in this process is recorded. The cathode copper is then separated, washed, and dried. Washing is done with alcohol and deionized water to remove residual electrolyte. Drying is performed in a vacuum drying oven. After treatment, the copper is weighed and vacuum-preserved, and the electrodeposition rate of this electrolysis process is calculated.

[0031] The collected data is shown in the table below: The high-purity copper obtained was tested for purity, and the purity was 99.98%. The contents of other elements are shown in the table below: Example 2 A method for preparing high-purity copper by electrolysis assisted by a magnetized electrolyte specifically includes the following steps: Step A: Prepare an electrolyte solution using copper sulfate pentahydrate (CuSO4·5H2O) as the raw material. The concentration of the prepared electrolyte solution is 0.01 mol / L. Adjust the pH of the electrolyte solution by adding dilute sulfuric acid using a pH meter. The concentration of the dilute sulfuric acid used is 1 mol / L. The target pH is 3. Too low a pH will aggravate hydrogen evolution. A pH of around 3 is more suitable. Step B involves using an ion exchange resin to perform ion exchange on the solution after pH adjustment in Step A. The ion exchange process involves first using a chelating resin to preferentially remove metallic impurities such as Co, Ni, and Fe, and then using a strong basic anion exchange resin and a boric acid-specific resin to remove non-metallic impurities such as P, Si, and B. After ion exchange, the impurity elements in the solution are significantly reduced. Specifically, the sum of the contents of Co, Ni, Fe, and Zn elements should not exceed 50 ppm, making the electrolyte purer and further preventing the deposition of copper ions on the cathode plate during the subsequent electrolytic preparation of copper. Step C: The electrolyte treated with the ion exchange resin is placed in a strong magnetic field device. The strong magnetic field device uses a CFM-12T-150-H3 steady-state strong magnetic field to apply a uniform and stable magnetic field to the electrolyte for a certain period of time. The magnetic field strength is 800 mT and the magnetization time is 30 min (excluding the time to increase the magnetic field strength to the target magnetic field strength) to magnetize the electrolyte. Step D: Use a pure copper plate as the anode (size 100*100*2mm) 3 The area used for electrolysis is greater than 40 cm². 2 The cathode is a pure titanium plate (100*100*2mm). 3 The area where electrolysis takes place is 40 cm². 2 Simultaneously, the magnetized electrolyte is placed in an electrolytic cell for electrolysis. To maintain consistent electrolysis conditions, the electrolytic cell is placed in a constant-temperature water bath at 25°C, and the cathode current density is 500 A / m. 2 To avoid the electrolyte being oxidized and contaminated under natural conditions due to prolonged electrolysis, the electrolysis time is controlled to be 2 hours. Electrolytic copper powder is obtained after electrolysis.

[0032] The subsequent processing was the same as in Example 1: weighing, recording power consumption, and calculating the electrodeposition rate of this electrolysis process. The collected data are shown in the table below: The high-purity copper obtained was tested for purity, and the purity was 99.97%. The contents of other elements are shown in the table below:

[0033] Example 3 A method for preparing high-purity copper using magnetized electrolyte-assisted electrolysis, the difference being that no magnetic field is used to magnetize the electrolyte, specifically including the following steps: Step A: Prepare an electrolyte solution using copper sulfate pentahydrate (CuSO4·5H2O) as the raw material. The concentration of the prepared electrolyte solution is 0.01 mol / L. Adjust the pH of the electrolyte solution by adding dilute sulfuric acid using a pH meter. The concentration of the dilute sulfuric acid used is 1 mol / L. The target pH is 3. Too low a pH will aggravate hydrogen evolution. A pH of around 3 is more suitable. Step B involves using an ion exchange resin to perform ion exchange on the solution after pH adjustment in Step A. The ion exchange process involves first using a chelating resin to preferentially remove metallic impurities such as Co, Ni, and Fe, and then using a strong basic anion exchange resin and a boric acid-specific resin to remove non-metallic impurities such as P, Si, and B. After ion exchange, the impurity elements in the solution are significantly reduced. Specifically, the sum of the contents of Co, Ni, Fe, and Zn elements should not exceed 50 ppm, making the electrolyte purer and further preventing the deposition of copper ions on the cathode plate during the subsequent electrolytic preparation of copper. Step C: In this embodiment, a magnetized electrolyte without a magnetic field is used; therefore, the ion-exchanged electrolyte is directly electrolyzed. A pure copper plate (100*100*2mm) is used as the anode. 3 The area used for electrolysis is greater than 40 cm². 2 The cathode is a pure titanium plate (100*100*2mm). 3 The area where electrolysis takes place is 40 cm². 2 Simultaneously, the magnetized electrolyte is placed in an electrolytic cell for electrolysis. To maintain consistent electrolysis conditions, the electrolytic cell is placed in a constant-temperature water bath at 25°C, and the cathode current density is 500 A / m. 2 To avoid the electrolyte being oxidized and contaminated under natural conditions due to prolonged electrolysis, the electrolysis time is controlled to be 2 hours. Electrolytic copper powder is obtained after electrolysis.

[0034] The subsequent processing was the same as in Example 1: weighing, recording power consumption, and calculating the electrodeposition rate of this electrolysis process. The collected data are shown in the table below: The purity of the obtained pure copper was tested and found to be 99.95%. The contents of other elements are shown in the table below:

[0035] The above three embodiments first purify the electrolyte to reduce the content of impurity elements, and then magnetize the electrolyte to study the effect of magnetic field pre-magnetization of the electrolyte on the electrolysis process, and obtained... Figure 1 , Figure 2 , Figure 3 Three results.

[0036] Figure 1 This compares the changes in electrodeposition rate in Examples 1, 2, and 3. In the graph, the vertical axis represents the increase in mass of the cathode plate (g), and the horizontal axis represents the magnetic field strength (T). Figure 1 It can be seen that for electrolytes enhanced by magnetic field, the average mass of the cathode plate increases by 3-5% after electrolysis, and the average mass increase rate further increases with the increase of magnetic field strength.

[0037] Figure 2This invention compares the changes in electrolytic energy consumption in Examples 1, 2, and 3. As the magnetic field strength used to magnetize the electrolyte increases from 0 T to 800 mT, the energy consumption for electrolytic copper shows a decreasing trend. At 0 T, the energy consumption is 4.492 kWh / kg, decreasing to 4.379 kWh / kg at 400 mT, and reaching 4.376 kWh / kg at 800 mT. The energy consumption decrease is significant in the 0-400 mT range, indicating a clear effect of the magnetic field in reducing energy consumption, possibly due to the magnetic field promoting electrolyte ion migration and optimizing electrode reaction kinetics. In the 400-800 mT range, the decrease slows down, indicating that the magnetic field enhancement effect gradually saturates, and the marginal benefit of further increasing the magnetic field for energy reduction decreases.

[0038] Figure 3 The figures show the detection results of the cathode electrolytic copper morphology in comparative examples 1, 2, and 3 of this invention. As can be seen from the figures, when the magnetic field strength increases from 0 T to 400 mT, the precipitate changes from dendritic crystals to nanotube crystals, and the crystal density and uniformity are improved. When the magnetic field strength continues to increase to 800 mT, the crystals change again, with some becoming coarse dendritic crystals, and the crystal uniformity decreases.

[0039] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing high-purity copper by electrolysis assisted by a magnetized electrolyte, characterized in that, Includes the following steps: 1) Obtain a copper salt solution to use as an electrolyte; 2) Remove impurities from the electrolyte obtained in step 1); 3) Magnetize the purified electrolyte; 4) The magnetized electrolyte obtained in step 3) is placed in an electrolysis device for electrolysis to obtain pure copper with a purity greater than or equal to 99.9% at the cathode. In the electrolysis device, the anode material is pure copper with a purity greater than or equal to 99%, and the cathode material is a carbon plate, a stainless steel plate, or a pure titanium plate.

2. The method for preparing high-purity copper by magnetized electrolyte-assisted electrolysis according to claim 1, characterized in that, In step 1): The copper salt is a copper sulfate salt or a copper nitrate salt; The concentration of the copper sulfate or copper nitrate is 0.01-0.02 mol / L.

3. The method for preparing high-purity copper by magnetized electrolyte-assisted electrolysis according to claim 1, characterized in that, In step 1): Add acid to the copper sulfate or copper nitrate solution to adjust the pH to 2-4.

4. The method for preparing high-purity copper by magnetized electrolyte-assisted electrolysis according to claim 1, characterized in that, In step 2): the electrolyte obtained in step 1) is first treated with chelating resin to remove metal impurities, and then non-metallic impurities are removed with strong basic anion exchange resin and boric acid special resin respectively. After impurity removal, the sum of the contents of Co, Ni, Fe and Zn elements is not higher than 50 ppm.

5. The method for preparing high-purity copper by magnetized electrolyte-assisted electrolysis according to claim 1, characterized in that, In step 3): In a strong magnetic field device, a uniform and stable magnetic field is applied to the purified electrolyte to magnetize it. The magnitude of the magnetic field is greater than 0 and less than or equal to 1000 mT, and the magnetization time is 20-30 min.

6. The method for preparing high-purity copper by magnetized electrolyte-assisted electrolysis according to claim 1, characterized in that, In step 4): Electrolysis is carried out in a constant temperature water bath at a temperature of 25-30℃.

7. The method for preparing high-purity copper by magnetized electrolyte-assisted electrolysis according to claim 1, characterized in that, In step 4): the current density of the cathode plate is 490-510 A / m. 2 .

8. The method for preparing high-purity copper by magnetized electrolyte-assisted electrolysis according to claim 1, characterized in that, In step 4), the electrolysis time is 1-3 hours.

9. The method for preparing high-purity copper by magnetized electrolyte-assisted electrolysis according to claim 1, characterized in that, In step 4): the distance between the anode and cathode of the electrolysis device is constant.

10. The method for preparing high-purity copper by magnetized electrolyte-assisted electrolysis according to any one of claims 1 to 9, characterized in that, In step 4): the energy consumption of electrolytic copper is reduced.

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