Method for electrolytic purification of blister copper smelted from scrap copper

Abstract

The application relates to an electrolytic purification method for crude copper smelted from waste copper. The electrolytic method comprises the following steps: preparing an anode plate with a specified size from a copper raw material containing impurities, placing the anode plate and a cathode plate into an electrolytic cell with prepared electrolyte, inputting direct current into the electrolytic cell, controlling the current density at 280-330 A / m 2 , starting a constant temperature device while electrolysis is carried out, keeping the temperature of the electrolyte at 60-70 DEG C, starting an electrolyte circulating pump, and making the electrolyte circulate at a speed of 3 L / min. An ultrasonic device is started, the frequency is controlled at 20-100 kHz, the power density is controlled at 0.5-3 W / cm 2 , and a continuous action time mode is adopted. The electrolysis is carried out for 12 hours. The scheme provided by the application can adapt to the electrolysis condition of the anode plate with high impurities, effectively reduce the occurrence of passivation, and improve the electrolysis efficiency and the quality of the cathode copper.

Description

Technical Field

[0001] This application belongs to the field of metallurgical engineering, specifically the field of hydrometallurgy, and relates to an electrolytic purification method for smelting crude copper from scrap copper. Background Technology

[0002] my country's copper resources are relatively scarce in both quantity and grade. Therefore, fully utilizing existing domestic scrap copper and improving the production technology and output of recycled copper is an environmentally friendly solution that can address current challenges in my country. When processing copper raw materials containing high levels of impurities, such as arsenic, antimony, bismuth, nickel, and iron, traditional electrolysis processes encounter a series of problems. Firstly, impurities may form a passivation film on the anode surface, hindering the normal dissolution of anode copper, leading to a significant decrease in electrolysis efficiency, increased cell voltage, and consequently, increased energy consumption. Secondly, impurity ions accumulate in the electrolyte and easily co-deposit with copper ions on the cathode surface, severely affecting the purity and quality of cathode copper, making it difficult to meet the stringent quality requirements of high-end applications. Furthermore, the presence of impurities can alter the properties of the electrolyte, increasing the difficulty and cost of purification. Therefore, developing a process that effectively addresses the electrolysis of copper with extremely high impurities is urgently needed. Summary of the Invention

[0003] The purpose of this application is to provide an electrolytic purification method for smelting crude copper from scrap copper. This method introduces ultrasonic external enhancement electrolysis under traditional electrolysis conditions, which can adapt to electrolysis conditions with high impurities in the anode plate, effectively reduce the occurrence of passivation, and improve electrolysis efficiency and the quality of cathode copper.

[0004] This application provides an electrolytic purification method for smelting crude copper from scrap copper, the electrolytic method comprising the following steps: S1, waste copper and copper ore are smelted by pyrometallurgy and cast into anode plates; S2, a waste copper electrolyte is prepared by mixing copper sulfate and sulfuric acid; the waste copper electrolyte contains 45-48 g / L of copper, 160-170 g / L of sulfuric acid, and ≤15 g / L of arsenic. S3, the anode plate and cathode plate made in S1 are placed into an electrolytic cell containing the electrolyte prepared in S2, and direct current is passed into the electrolytic cell to carry out electrolysis. At the same time, the constant temperature device, electrolyte circulation pump and ultrasonic device are started.

[0005] Furthermore, the current density of the DC current in S3 is controlled at 280-330 A / m. 2 .

[0006] Furthermore, the temperature of the constant temperature device in S3 is 60-70℃.

[0007] Furthermore, the electrolyte circulation pump in S3 has an electrolyte flow rate of 3 L / min.

[0008] Furthermore, the ultrasonic device in S3 has a frequency of 20-100kHz and a power density of 0.5-3W / cm². 2 .

[0009] Furthermore, the electrolysis time in S3 is 12 hours.

[0010] Furthermore, the anode plate in S1 has dimensions of 88×85mm, a thickness of 9-11mm, and a mass of 0.6-0.7kg.

[0011] Furthermore, in S3, there are 8 anode plates and 8 cathode plates.

[0012] Furthermore, in S3, the cathode plate is composed of a conductive rod, a stainless steel plate, and an insulating clamping strip.

[0013] Beneficial effects 1. The present application provides an electrolytic purification method for smelting crude copper from scrap copper. Under traditional electrolytic conditions, ultrasonic external enhancement electrolysis is introduced, which can adapt to electrolytic conditions with high impurities in the anode plate, effectively reduce the occurrence of passivation, improve electrolytic efficiency and the quality of cathode copper, and the purity of the cathode copper after testing reaches 99.99%.

[0014] 2. The cathode plate of this application is made of stainless steel, and the reusable cathode deposition surface is used to precipitate high-purity plate-shaped cathode copper.

[0015] 3. The vibration energy of the ultrasonic device reduces the adsorption and retention of hydrogen on the cathode surface, reduces the generation of defects such as pinholes and pores, and improves the density of the cathode copper, as well as the conductivity and mechanical strength.

[0016] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Detailed Implementation

[0017] The embodiments of this application will now be described in more detail. While embodiments of this application are shown below, 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.

[0018] The significant role of ultrasound in copper electrolysis stems from the combined effect of its unique physical properties and electrochemical processes. The specific technical principles are as follows: 1. The core driving force of cavitation is the key to ultrasonic intervention in copper electrolysis. When ultrasound (typically with a frequency of 20-100kHz) propagates in the electrolyte, it periodically generates pressure fluctuations, forming numerous tiny bubbles (cavitation nuclei). These bubbles expand rapidly under negative pressure and collapse instantaneously under positive pressure, releasing extremely strong shock waves (local pressures reaching thousands of atmospheres) and microjets. This intense physical impact directly breaks the diffusion boundary layer on the electrode surface—the main source of resistance to ion migration in traditional electrolysis. This significantly alleviates concentration polarization, creating conditions for increasing current density and shortening the electrolysis cycle. Simultaneously, the localized high temperature (up to thousands of degrees Celsius) and high pressure environment generated by bubble collapse promotes the formation of stable complexes or precipitates of impurity ions (such as arsenic, antimony, and bismuth) in the electrolyte, reducing their co-deposition probability on the cathode surface.

[0019] 2. The synergistic optimization effect of mechanical vibration further enhances the electrolysis process. The high-frequency vibration of ultrasound (tens of thousands of times per second) is transmitted to the electrolyte and electrodes. On the one hand, it causes the electrolyte to form macroscopic circulation and microscopic eddies, accelerating the overall migration and uniform distribution of ions and avoiding uneven cathode deposition caused by local concentration imbalances. On the other hand, the vibration energy can directly act on the anode surface, promptly removing the attached anode sludge. If these loose layers formed by impurities are not removed in time, they will gradually transform into a passivation film.

[0020] 3. The auxiliary regulatory role of thermal effects. When ultrasound propagates in the medium, some of its energy is converted into heat, causing a uniform increase in electrolyte temperature. This temperature increase not only reduces electrolyte viscosity and further accelerates ion diffusion, but also enhances the kinetic activity of electrode reactions and reduces electrochemical polarization resistance. This gentle heating method avoids the localized overheating problems that can occur with traditional external heating, ensuring stable operation of the electrolytic system within a more optimal temperature range. It is particularly suitable for scenarios requiring precise control of reaction conditions in high-impurity systems.

[0021] 4. The microscopic control of the crystallization process improves the quality of cathode copper. During the cathode copper deposition stage, the energy of ultrasound can disrupt the thermodynamic equilibrium of crystal growth: the microjets generated by cavitation bubble collapse interrupt the growth of excessively large copper grains, promoting the formation of more crystal nuclei, thereby refining the grains and forming a denser, smoother deposition layer. Simultaneously, vibration reduces the adsorption and retention of hydrogen on the cathode surface, decreasing the generation of defects such as pinholes and pores, thus increasing the density of the cathode copper and simultaneously improving its conductivity and mechanical strength.

[0022] In summary, ultrasound, through the combined effects of cavitation, mechanical vibration, and thermal effects, improves the copper electrolysis process in multiple dimensions, from mass transfer enhancement, impurity control, reaction kinetic optimization to crystallization regulation. When processing high-impurity copper raw materials, it can effectively alleviate problems such as passivation, uneven deposition, and excessive energy consumption faced by traditional processes, providing reliable technical support for improving electrolysis efficiency and product quality.

[0023] Unless otherwise specified, all reagents and materials used in the following examples were purchased from the market.

[0024] The specific steps are as follows: Preparation of crude copper anode plates: Waste copper and copper ore are smelted by pyrometallurgy and cast into anode plates. The anode plates are 88×85mm in size, about 9-11mm thick, and weigh about 0.67kg.

[0025] Electrolyte preparation: A mixed solution prepared from copper sulfate and sulfuric acid. The copper content in the waste copper electrolyte is 45-48 g / L, the sulfuric acid content is 160-170 g / L, and the arsenic content is ≤15 g / L.

[0026] Ultrasonic generator: Ultrasonic parameters: frequency controlled between 20-100kHz, power density controlled between 0.5-3W / cm²; Operating mode and time: continuous or intermittent operation should be selected as needed. Continuous operation is suitable for conventional electrolysis with stable impurity content and can maintain mass transfer efficiency continuously; intermittent operation (such as working for 30 seconds and stopping for 10 seconds) can reduce the impact of cavitation bubble accumulation on the electrodes.

[0027] Cathode Plate: The cathode is made of stainless steel plate. The stainless steel cathode method utilizes stainless steel plate as a reusable cathode deposition surface to precipitate high-purity plate-shaped cathode copper, making it one of the main process equipment for copper smelting and copper resource recovery. The stainless steel cathode plate consists of conductive rods, a stainless steel plate, and insulating edge strips.

[0028] Process: Anode plates of specified dimensions are prepared from copper raw materials containing impurities. These anode plates and cathode plates are then placed at a certain interval into an electrolytic cell containing prepared electrolyte; 8 anode plates and 8 cathode plates are used. Direct current is passed into the electrolytic cell, with the current density controlled at 280-330 A / m. 2 Copper at the anode loses electrons to become copper ions, which enter the electrolyte. Under the influence of the electric field, these copper ions move towards the cathode, gain electrons, and are deposited on the cathode plate. Simultaneously, a thermostat is activated to maintain the electrolyte temperature between 60-70°C, and the electrolyte circulation pump is turned on at a rate of 3 L / min. An ultrasonic device is activated, with the frequency controlled between 20-100 kHz and the power density controlled between 0.5-3 W / cm³. 2 Electrolysis was performed for 12 hours using a continuous action time method.

[0029] Example 1 Using copper raw material with a copper grade of 97.5%, arsenic content of 1.2%, antimony content of 0.75%, and bismuth content of 0.55%, an anode plate with dimensions of 88×85mm, a thickness of approximately 9mm, and a weight of approximately 0.6kg was fabricated. Eight anode plates and eight cathode plates were placed alternately in the electrolytic cell, spaced 99mm apart. A pre-prepared electrolyte was injected, containing 45g / L copper, 160g / L sulfuric acid, and 15g / L arsenic. A direct current was applied, with the current density controlled at 280A / m. 2 The electrolyte circulation rate was 3 L / min. After 12 hours of electrolysis, the power was stopped. The cathode plate was removed, and the pure copper was peeled off. Samples were taken for testing, and the purity of the cathode copper reached 99.95%.

[0030] Example 2 Using copper raw materials with a copper grade of 97.5%, arsenic content of 1.2%, antimony content of 0.75%, and bismuth content of 0.55%, an anode plate with dimensions of 88×85mm, a thickness of approximately 10mm, and a weight of approximately 0.67kg was fabricated. Eight anode plates and eight cathode plates were placed alternately in the electrolytic cell, spaced 99mm apart. A pre-prepared electrolyte was injected, containing 45g / L copper, 160g / L sulfuric acid, and 15g / L arsenic. A direct current was applied, with the current density controlled at 280A / m. 2 The electrolyte circulation rate was 3 L / min, the ultrasonic equipment was turned on, the frequency was adjusted to 30 kHz, and the power density was adjusted to 1 W / cm³. 2 After 12 hours of electrolysis, the power was turned off. The ultrasonic equipment was then put into use. As the ultrasound propagated in the medium, some of its energy was converted into heat, causing the electrolyte temperature to rise uniformly by 5°C. This temperature increase not only reduced the electrolyte viscosity but also accelerated ion diffusion, improved the kinetic activity of the electrode reaction, and reduced electrochemical polarization resistance. The vibration energy also reduced the adsorption and retention of hydrogen on the cathode surface, decreasing the formation of defects such as pinholes and pores, thus increasing the density of the cathode copper by 11%. The cathode plate was removed, and the pure copper was peeled off. Sampling and testing showed that the cathode copper purity reached 99.99%.

[0031] Example 3 Using copper raw materials with a copper grade of 98%, arsenic content of 1%, antimony content of 0.65%, and bismuth content of 0.35%, an anode plate with dimensions of 88×85mm, a thickness of approximately 11mm, and a weight of approximately 0.7kg was manufactured. Eight anode plates and eight cathode plates were placed alternately in the electrolytic cell, spaced 99mm apart. A pre-prepared electrolyte was injected, containing 45g / L copper, 160g / L sulfuric acid, and 15g / L arsenic. A direct current was applied, with the current density controlled at 280A / m.2 The electrolyte circulation rate was 3 L / min, the ultrasonic equipment was turned on, the frequency was adjusted to 50 kHz, and the power density was adjusted to 2 W / cm². 2 After 12 hours of electrolysis, the power was turned off. The ultrasonic equipment was then put into use. As the ultrasound propagated in the medium, some of its energy was converted into heat, causing the electrolyte temperature to rise uniformly by 8.5°C. This temperature increase not only reduced the electrolyte viscosity but also accelerated ion diffusion, improved the kinetic activity of the electrode reaction, and reduced electrochemical polarization resistance. The vibration energy also reduced the adsorption and retention of hydrogen on the cathode surface, decreasing the formation of defects such as pinholes and pores, thus increasing the density of the cathode copper by 18%. The cathode plate was removed, and the pure copper was peeled off. Sampling and testing showed that the cathode copper purity reached 99.993%.

[0032] 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 method for electrolytic purification of crude copper from scrap copper smelting, characterized in that, The electrolysis method includes the following steps: S1, waste copper and copper ore are smelted by pyrometallurgy and cast into anode plates; S2, a waste copper electrolyte is prepared by mixing copper sulfate and sulfuric acid; the waste copper electrolyte contains 45-48 g / L of copper, 160-170 g / L of sulfuric acid, and ≤15 g / L of arsenic. S3, the anode plate and cathode plate made in S1 are placed into an electrolytic cell containing the electrolyte prepared in S2, and direct current is passed into the electrolytic cell to carry out electrolysis. At the same time, the constant temperature device, electrolyte circulation pump and ultrasonic device are started.

2. The electrolysis method according to claim 1, characterized in that, The DC current density in S3 is controlled at 280-330 A / m. 2 .

3. The electrolysis method according to claim 1, characterized in that, The temperature of the constant temperature device in S3 is 60-70℃.

4. The electrolysis method according to claim 1, characterized in that, The electrolyte circulation pump in S3 has an electrolyte flow rate of 3 L / min.

5. The electrolysis method according to claim 1, characterized in that, The ultrasonic device in S3 has a frequency of 20-100kHz and a power density of 0.5-3W / cm². 2 .

6. The electrolysis method according to claim 1, characterized in that, The electrolysis time in S3 is 12 hours.

7. The electrolysis method according to claim 1, characterized in that, The anode plate in S1 has dimensions of 88×85mm, a thickness of 9-11mm, and a mass of 0.6-0.7kg.

8. The electrolysis method according to claim 1, characterized in that, The number of anode plates and cathode plates in S3 is 8 each.

9. The electrolysis method according to claim 1, characterized in that, The cathode plate in S3 consists of a conductive rod, a stainless steel plate, and an insulating edge strip.