A method for reducing DC power consumption by adjusting the anode polarization potential in copper electrolysis

Abstract

This invention discloses a method for reducing DC power consumption by adjusting the anode polarization potential in copper electrolysis. The method involves adding additive A and an anode polarization potential-reducing additive during electrolysis. The concentration of the anode polarization potential-reducing additive is adjusted according to voltage changes in the electrolytic cell during electrolysis to suppress anode passivation and simultaneously accelerate the cuprous ion to copper ion reaction rate, thereby reducing the anode polarization potential and ensuring normal copper electrolysis while reducing DC power consumption. This invention uses organic additives to suppress anode passivation and accelerate the cuprous ion to copper ion reaction rate to reduce the anode polarization potential, thus achieving the goal of reducing DC power consumption. It has advantages such as simple operation, wide adaptability, and significant power consumption reduction effect.

Description

Technical Field

[0001] This invention relates to the field of copper electrolytic refining, and more particularly to a method for adjusting the anode polarization potential of copper electrolysis to reduce DC power consumption. Background Technology

[0002] In the copper electrolytic refining process, DC power consumption is a crucial indicator, significantly impacting the economic efficiency of electrolytic copper production, accounting for approximately 60% of the total cost. Many factors influence DC power consumption in copper electrolysis, which, based on theoretical calculation formulas, can be categorized into two types: those affecting cell voltage and those affecting current efficiency. To reduce DC power consumption in copper electrolysis, researchers generally focus on these two categories of factors. Current research largely concentrates on the impact of process conditions on DC power consumption, such as the relationship between electrolyte composition, electrolyte temperature, current density, and electrode spacing, all aimed at reducing cell voltage. Cell voltage is negatively correlated with acid concentration in the electrolyte and positively correlated with the concentration of copper and other impurities; cell voltage decreases with increasing temperature; higher current density results in higher cell voltage; and a larger electrode spacing results in higher cell voltage. In actual production, the concentration of copper acid needs to meet certain ranges for normal operation; cell voltage cannot be reduced by infinitely increasing acid concentration and decreasing copper concentration. Similarly, while increasing the temperature can reduce cell voltage, excessively high temperatures can introduce large amounts of acid mist into the electrolysis workshop, worsening the working environment and impacting workers' health. It can also cause the copper ion concentration in the electrolyte to rise too quickly, increasing the net electrolyte volume. Reducing the current density leads to decreased production efficiency, and reducing the electrode spacing increases the likelihood of short circuits. As the above analysis shows, adjusting process conditions such as temperature, current density, and electrode spacing to reduce DC power consumption has significant limitations, and improper operation may even have the opposite effect. Summary of the Invention

[0003] This invention discloses a method for adjusting the anode polarization potential of copper electrolysis to reduce DC power consumption, thereby solving any of the above-mentioned technical problems in the prior art and other potential problems.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is: a method for adjusting the anode polarization potential of copper electrolysis to reduce DC power consumption. In this method, additive A and an additive for reducing anode electrolysis potential are first added during the electrolysis process. Then, the concentration of the additive for reducing anode electrolysis potential is adjusted according to the voltage change in the electrolytic cell during the electrolysis process to inhibit anode passivation and accelerate the reaction rate of cuprous ions to copper ions, thereby reducing the anode polarization potential, enabling the normal operation of copper electrolysis, and reducing the DC power consumption during the copper electrolysis process.

[0005] Furthermore, the method specifically includes: S1) First, soak the anode in the electrolyte to remove the oxides on the anode surface. After soaking, rinse with clean water, introduce the electrolyte again, and start the steam and circulation of the electrolysis system.

[0006] S2) Additive A and an additive to reduce the anode electrode potential are added to the electrolysis system at a certain concentration through an automatic additive addition system. The concentration of the additive to reduce the anode electrolysis potential is then adjusted according to the voltage change in the electrolytic cell during the electrolysis process. This inhibits anode passivation and accelerates the reaction rate of cuprous ions to copper ions, thereby reducing the polarization potential of the anode, enabling the normal operation of copper electrolysis, and reducing the DC power consumption during the copper electrolysis process.

[0007] Furthermore, the electrolyte temperature in S1) is controlled at 60-65°C, and the soaking time is controlled at 5-60 min.

[0008] Furthermore, the concentration of additive A in S2) is 1-100 mg / L; the concentration of additive to reduce the anode electrode potential is 1-200 mg / L.

[0009] The adjustment method is as follows: for every 5-15mV increase in cell voltage relative to the first day of the electrolysis cycle, the concentration of copper anode additive will be increased by 1-3mg / L.

[0010] Furthermore, the concentration of additive A in S2) is 10-60 mg / L.

[0011] Furthermore, additive A is one or more of bone glue, gelatin, avitamin, thiourea, casein, and chloride ions.

[0012] Furthermore, the additive for reducing the anode electrode potential is an additive containing two or more elements, namely C, N, O, H, and S.

[0013] Furthermore, the additives containing two or more elements of C, N, O, H, and S include one or more of the following: tartaric acid, potassium sodium tartrate tetrahydrate, ascorbic acid, citric acid, sodium citrate, nitrilotriacetic acid, polyacrylic acid, and polymaleic acid.

[0014] Furthermore, the additive containing two or more elements of C, N, O, H, and S is ascorbic acid or sodium citrate.

[0015] Furthermore, during the process of the method, the average cell voltage drop is not less than 9.8mV, the DC power consumption drop is not less than 4.53%, and the cathode current efficiency is not less than 94.11%.

[0016] A type of Grade A copper, which is prepared by the method described above.

[0017] The electrolysis system includes a rectifier, an electrolytic cell, a circulation tank, a circulation pump, a heat exchanger, and an elevated tank. The electrolytic cell is connected to the inlet of the circulation tank, the outlet of the circulation tank is connected to the inlet of the circulation pump, the outlet of the circulation pump is connected to the inlet of the elevated tank, and the outlet of the elevated tank is connected to the electrolytic cell, forming a circulation loop. All connections are made via pipelines.

[0018] The electrolysis system also includes an automatic additive addition system: specifically, it includes an additive tank and a peristaltic pump. The additive tank is equipped with a stirrer, and an additive solution is obtained by stirring and dissolving a certain proportion of additive and water. The anode potential lowering additive tank is located near the anode, while the conventional additive tank is located near the circulation tank. The conventional additive is added to the circulation tank of the electrolysis system via a rubber tube and a peristaltic pump. The anode potential lowering additive is added directly to the electrolysis cell near the anode via a peristaltic pump. During electrolysis, the cell voltage is monitored. For every 5–15 mV increase in cell voltage relative to the first day of the electrolysis cycle, the concentration of the copper anode lowering additive is increased by 1–3 mg / L.

[0019] The principle of this invention is as follows:

[0020] During the oxidation of copper at the anode to copper ions, hydrogen ions in the electric double layer near the anode are continuously consumed. When the pH increases above 2.25, copper reacts to form cuprous oxide. A portion of the cuprous oxide can further lose an electron to form copper ions, as shown in the following reaction: Cu₂O + 2H₂O + -2e - =Cu 2+ +H2O.

[0021] As hydrogen ions are continuously consumed at the electric double layer, another portion of cuprous oxide cannot gain electrons in time and remains on the copper anode surface in the form of cuprous oxide, forming a layer of copper powder on the anode surface. This causes anode passivation, which significantly increases the anode potential and leads to an increase in DC power consumption.

[0022] The additive used in this invention can be adsorbed in the anodic double layer. By releasing its own hydrogen ions or reacting to generate hydrogen ions, it effectively replenishes the hydrogen ions in the double layer, preventing the formation of cuprous oxide from copper. In the presence of sufficient hydrogen ions, it can also promote the further formation of copper ions from cuprous oxide. In addition, the anions in the additive of this invention can also undergo complexation reactions with copper ions in the double layer, accelerating the reaction rate of cuprous ion to copper ion conversion, thereby reducing the anodic potential.

[0023] The beneficial effects of this invention are as follows: Due to the adoption of the above technical solution, the method of this invention differs from traditional methods that reduce DC power consumption by adjusting electrolysis process conditions. This invention proposes a new method that reduces the anodic polarization potential by suppressing anode passivation and simultaneously accelerating the reaction rate from cuprous ions to copper ions, thereby achieving the goal of reducing DC power consumption. The method of this invention is simple to operate, highly adaptable, and has a significant effect on reducing power consumption. Attached Figure Description

[0024] Figure 1 This is a flowchart of a method for reducing DC power consumption by adjusting the anode polarization potential in copper electrolysis.

[0025] Figure 2 This is a photographic schematic diagram of the cathode copper produced using the method of the present invention in Example 1.

[0026] Figure 3 A schematic diagram of the cathode copper production process in Comparative Example 1. Detailed Implementation

[0027] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0028] like Figure 1 As shown, the present invention provides a method for reducing DC power consumption by adjusting the anode polarization potential of copper electrolysis. The method specifically comprises:

[0029] S1) First, soak the anode in the electrolyte to remove the oxides on the anode surface. After soaking, rinse with clean water, introduce the electrolyte again, and turn on the steam and circulation of the electrolysis system.

[0030] Temperature should be controlled at 60-65℃, and soaking time should be controlled at 5-60 minutes;

[0031] S2) Additive A is added to the electrolysis system at a concentration of 1–100 mg / L via an automatic additive addition system, and an additive to reduce the anode electrode potential is added at a concentration of 1–200 mg / L.

[0032] Based on the voltage on the first day of the electrolysis cycle, the concentration of additives to reduce the anode electrolysis potential is adjusted according to the voltage changes in the electrolytic cell during the electrolysis process. This suppresses anode passivation and accelerates the reaction rate of cuprous ions to copper ions, thereby reducing the polarization potential of the anode, enabling normal copper electrolysis, and reducing DC power consumption during the copper electrolysis process.

[0033] The concentration of additive A in S2) is 1-100 mg / L; the concentration of additive to reduce the anode electrode potential is 1-200 mg / L, according to the method of claim 1.

[0034] The concentration of additive A in S2) is 10-60 mg / L.

[0035] Additive A is one or more of bone glue, gelatin, avitamin, thiourea, casein, and chloride ions.

[0036] The additive that reduces the anode electrode potential is an additive containing two or more elements, namely C, N, O, H, and S.

[0037] The additives containing two or more elements of C, N, O, H, and S include one or more of the following: tartaric acid, potassium sodium tartrate tetrahydrate, ascorbic acid, citric acid, sodium citrate, nitrilotriacetic acid, polyacrylic acid, and polymaleic acid.

[0038] The additive containing two or more elements of C, N, O, H, and S is ascorbic acid or sodium citrate.

[0039] During the process described, the average cell voltage drop is not less than 9.8 mV, the DC power consumption drop is not less than 4.53%, and the cathode current efficiency is not less than 94.11%.

[0040] Example 1

[0041] Five low-arsenic anodes were immersed in an electrolytic cell containing 60°C electrolyte for 30 minutes to remove oxides from the anode surface and prevent them from affecting dissolution. After rinsing, the anodes were rinsed with clean water until no copper powder adhered to the surface. Clean electrolyte was then introduced again, and four cathodes were placed in the cell. The steam and circulation systems of the electrolysis system were then turned on. Conventional additives, including bone glue, thiourea, and hydrochloric acid, were added to the electrolysis system via an automatic additive addition system, with concentrations controlled at 3 mg / L, 2 mg / L, and 60 mg / L, respectively. Additives to reduce the anode polarization potential were ascorbic acid and sodium citrate, with initial concentrations controlled at 30 mg / L and 15 mg / L, respectively. The current density was adjusted to 300 A / m. 2 The electrolysis cycle was 10 days. On the 10th day of the electrolysis cycle, the concentrations of the anodic polarization potential additives, ascorbic acid and sodium citrate, were reduced to 32 mg / L and 16 mg / L, respectively. At the end of the electrolysis cycle, the rectifier cell voltage was as shown in Table 1, with an average cell voltage of 356.2 mV. The cathode copper weighed 665.3 kg. Calculations showed that the cathode current efficiency was 97.36%, and the DC power consumption was 308.48 kWh / ton of copper.

[0042] Table 1. Electrolytic cell voltage variation (mV)

[0043] Days 1 2 3 4 5 6 7 8 9 10 slot pressure 355 355 353 355 354 356 356 358 359 361

[0044] Comparative Example 1

[0045] Five low-arsenic anodes were immersed in an electrolytic cell containing 60°C electrolyte for 30 minutes to remove oxides from the anode surface and prevent them from affecting dissolution. After rinsing, the anodes were rinsed with clean water until no copper powder adhered to the surface. Clean electrolyte was then introduced again, and four cathodes were placed in the cell. The steam and circulation systems of the electrolysis system were then activated. Conventional additives, bone glue, thiourea, and hydrochloric acid, were added to the electrolysis system via an automatic additive addition system, with concentrations controlled at 3 mg / L, 2 mg / L, and 60 mg / L, respectively. No additives to reduce anode polarization were added, and the current density was adjusted to 300 A / m. 2 The electrolysis cycle is 10 days. The rectifier cell voltage at the end of electrolysis is shown in Table 2. The average cell voltage is 385.6 mV. The cathode copper weighs 642.9 kg. The calculated cathode current efficiency is 94.11% and the DC power consumption is 345.47 kWh / ton of copper.

[0046] Table 2 Electrolytic Cell Voltage Variation (mV)

[0047] Days 1 2 3 4 5 6 7 8 9 10 slot pressure 373 371 376 381 386 383 389 398 394 405

[0048] The comparison shows that, under these conditions, the example with the additive to reduce anodic polarization has an average cell voltage that is 29.4 mV lower and a DC power consumption that is 10.71% lower than the example without the additive. This is because the cell voltage is higher when the additive is not added, and the anode may have undergone slight passivation, resulting in reduced current efficiency and increased DC power consumption.

[0049] Furthermore, comparing the cathode copper content and cathode surface quality of Example 1 and Comparative Example 1, as shown in Table 3, it can be found that the cathode impurity content all meet the Cu-CATH-1 (Grade A copper) standard in GB / T 467-2010, indicating that the reduction of anodic polarization additives acts on the anode and does not affect the cathode impurity content; Figure 2 and Figure 3 As shown, the cathode plates obtained in Example 1 and Comparative Example 1 both have smooth and flat surfaces with no obvious particles. This indicates that after adding the additive to reduce anodic polarization, the purity and physical quality of the cathode both meet the Grade A copper standard, making it suitable for industrial production applications.

[0050] Table 3. Chemical composition of cathode copper in Example 1 and Comparative Example 1

[0051]

[0052] Example 2

[0053] Five normal anodes were immersed in an electrolytic cell containing 60°C electrolyte for 30 minutes to remove oxides from the anode surface and prevent them from affecting dissolution. After rinsing, the anodes were rinsed with clean water until no copper powder adhered to the surface. Clean electrolyte was then introduced again, and four cathodes were placed in the cell. The steam and circulation systems of the electrolysis system were then turned on. Conventional additives, including bone glue, thiourea, abamectin, and hydrochloric acid, were added to the electrolysis system via an automatic additive addition system, with concentrations controlled at 2.5 mg / L, 10 mg / L, 0.5 mg / L, and 60 mg / L, respectively. Tartaric acid and polyacrylic acid were added to reduce the anode polarization potential, with initial concentrations controlled at 15 mg / L and 50 mg / L, respectively. The current density was adjusted to 300 A / m. 2 The electrolysis cycle was 10 days. Tartaric acid and polyacrylic acid were added to reduce the anodic polarization potential. The concentrations were adjusted to 16 mg / L and 52 mg / L on day 5, 18 mg / L and 55 mg / L on day 7, 19 mg / L and 57 mg / L on day 8, and 20 mg / L and 60 mg / L on day 10. At the end of electrolysis, the average cell voltage of the rectifier was 366.4 mV, and the cathode copper weighed 670.1 kg. The calculated cathode current efficiency was 98.09%, and the DC power consumption was 314.95 kWh / ton of copper.

[0054] Table 3 Electrolytic cell voltage variation / mV

[0055] Days 1 2 3 4 5 6 7 8 9 10 slot pressure 359 361 361 360 365 368 371 374 369 376

[0056] Comparative Example 2

[0057] Five normal anodes were immersed in an electrolytic cell containing 60°C electrolyte for 30 minutes to remove oxides from the anode surface and prevent them from affecting dissolution. After rinsing, the anodes were rinsed with clean water until no copper powder adhered to the surface. Clean electrolyte was then introduced again, and four cathodes were placed in the cell. The steam and circulation systems of the electrolysis system were then turned on. Conventional additives, including bone glue, thiourea, abamectin, and hydrochloric acid, were added to the electrolysis system via an automatic additive addition system, with concentrations controlled at 2.5 mg / L, 10 mg / L, 0.5 mg / L, and 60 mg / L, respectively. No additives to reduce anode polarization potential were added, and the current density was adjusted to 300 A / m. 2 The electrolysis cycle is 10 days. At the end of the electrolysis, the average cell voltage of the rectifier is 375.2 mV, and the cathode copper weighs 655.1 kg. The calculated cathode current efficiency is 95.90%, and the DC power consumption is 329.88 kWh / ton of copper.

[0058] Table 4 Electrolytic Cell Voltage Variation (mV)

[0059] Days 1 2 3 4 5 6 7 8 9 10 slot pressure 361 363 367 369 373 373 382 384 389 394

[0060] The comparison shows that, under these conditions, the example with the additive to reduce anodic polarization has an average cell voltage that is 9.8 mV lower and DC power consumption that is 4.53% lower than the example without the additive.

[0061] It can be seen that among all the additives for reducing anodic polarization, the combination of ascorbic acid and sodium citrate has the most significant effect on reducing power consumption. Therefore, the preferred additives for reducing anodic polarization are ascorbic acid and sodium citrate.

[0062] The above provides a detailed description of a method for reducing DC power consumption by adjusting the anodic polarization potential of copper electrolysis, as provided in the embodiments of this application. The descriptions of the embodiments above are merely for the purpose of helping to understand the method and its core ideas; furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

[0063] Certain terms are used in the specification and claims to refer to specific components. Those skilled in the art will understand that hardware manufacturers may use different names to refer to the same component. This specification and claims do not distinguish components based on differences in name, but rather on differences in function. The terms "comprising" and "including" used throughout the specification and claims are open-ended and should be interpreted as "comprising / including but not limited to". "Approximately" means that within an acceptable margin of error, those skilled in the art can solve the technical problem and substantially achieve the technical effect within a certain margin of error. The following descriptions in the specification are preferred embodiments for carrying out this application; however, these descriptions are for the purpose of illustrating the general principles of this application and are not intended to limit the scope of this application. The scope of protection of this application shall be determined by the appended claims.

[0064] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a product or system comprising a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a product or system. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the product or system that includes said element.

[0065] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0066] The foregoing description illustrates and describes several preferred embodiments of this application. However, as previously stated, it should be understood that this application is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the application concept described herein through the foregoing teachings or techniques or knowledge in related fields. Any modifications and variations made by those skilled in the art that do not depart from the spirit and scope of this application should be within the protection scope of the appended claims.

Claims

1. A method for reducing DC power consumption by adjusting the anodic polarization potential of copper electrolysis, characterized in that, The method involves adding additive A and an additive to lower the anode electrode potential during electrolysis. The concentration of the additive lowering the anode electrode potential is adjusted according to voltage changes in the electrolytic cell during electrolysis to suppress anode passivation and simultaneously accelerate the reaction rate from cuprous ions to copper ions, thereby reducing the anode polarization potential and ensuring normal copper electrolysis while reducing DC power consumption. Specifically, the method is as follows: S1) First, soak the anode in the electrolyte to remove the oxides on the anode surface. After soaking, rinse with clean water, introduce the electrolyte again, and turn on the steam and circulation of the electrolysis system. S2) Additive A and an additive to reduce the anode electrode potential are added to the electrolysis system at a certain concentration through an automatic additive addition system. The concentration of the additive to reduce the anode electrode potential is then adjusted according to the voltage change in the electrolytic cell during the electrolysis process to inhibit anode passivation and accelerate the reaction rate of cuprous ions to copper ions, thereby reducing the polarization potential of the anode, enabling the normal operation of copper electrolysis, and reducing the DC power consumption during the copper electrolysis process. The concentration of additive A is 1-100 mg / L; the concentration of additive to reduce anode electrode potential is 1-200 mg / L; the adjustment method is: for every 5-15 mV increase in cell voltage relative to the first day of the electrolysis cycle, the concentration of the copper anode reducing additive is increased by 1-3 mg / L. Additive A is one or more of bone glue, gelatin, avitamin, thiourea, casein, and chloride ions; The additive that reduces the anode electrode potential is an additive containing two or more elements, namely C, N, O, H, and S. The additives containing two or more elements of C, N, O, H, and S include one or more of the following: tartaric acid, potassium sodium tartrate tetrahydrate, ascorbic acid, citric acid, sodium citrate, nitrilotriacetic acid, polyacrylic acid, and polymaleic acid.

2. The method according to claim 1, characterized in that, The electrolyte temperature in S1) is controlled at 60-65°C, and the soaking time is controlled at 5-60 minutes.

3. The method according to claim 1, characterized in that, The concentration of additive A in S2) is 10-60 mg / L.

4. The method according to claim 1, characterized in that, During the process described, the average cell voltage drop is not less than 9.8 mV, the DC power consumption drop is not less than 4.53%, and the cathode current efficiency is not less than 95.90%.

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