Method for reducing antimony and bismuth content in copper electrolyte

Abstract

The invention belongs to the hydrometallurgy industry, and particularly discloses a method for reducing the content of antimony and bismuth in copper electrolyte. The method comprises the following steps: detecting arsenic, antimony and bismuth contents of each batch of copper anode plates loaded into a copper electrolytic bath; under the condition that the arsenic content concentration in the electrolyte is 8-20 g / L, calculation is carried out according to the antimony content and the bismuth content in the copper anode plate, the number of the electrolytic cells changed into electrodeposition cells is determined through calculation, the copper anode plate in the electrolytic cell needing to be changed is lifted out and loaded into an inert anode plate, and the electrolytic cell is changed into the electrodeposition cell; under the condition that the electrodeposition cell is electrified, the flow of the circulating electrolyte in the electrodeposition cell is controlled, pentavalent arsenic in the copper electrolyte is converted into trivalent arsenic, and most of antimony and bismuth enter copper anode slime through the mechanism that the trivalent arsenic, antimony and bismuth are co-precipitated, so that the content of antimony and bismuth in the copper electrolyte is reduced, and the copper electrolyte meets the requirements. The method has the advantages of convenience in operation, low investment, low energy consumption, low cost and the like.

Description

1. Technical field:

[0001] The invention belongs to the hydrometallurgical industry, and in particular relates to a method for reducing the antimony and bismuth content in a copper electrolyte. 2. Background technology:

[0002] With the increase in refined copper production year by year, the competition in the copper market is becoming more and more fierce. The impurity content of commercially available copper concentrate raw materials is getting higher and higher. The content of antimony and bismuth, the impurity elements that affect the quality of cathode copper the most, is also getting higher and higher, resulting in high antimony and bismuth in anode copper. During the copper electrolytic refining process, arsenic, antimony, and bismuth, impurity elements in anode copper with a potential close to copper but more negative than copper, enter the copper electrolyte at a certain distribution ratio and gradually accumulate. Under different process conditions, the distribution ratio varies greatly. Most of them are 60-80% arsenic entering the electrolyte, 10-60% antimony entering the electrolyte, 20-40% bismuth entering the electrolyte, and the rest entering the anode mud. Arsenic, antimony, and bismuth entering the copper electrolyte will not only deposit on the cathode, but also form floating anode mud, affecting the quality of cathode copper. Therefore, the removal of arsenic, antimony, and bismuth impurities is the main goal of copper electrolyte purification. Electrolysis is widely used in the purification process of copper electrolyte. When electrolysis is used, in order to ensure the balance of copper in the electrolytic-cleaned liquid, the antimony and bismuth content in the electrolyte is sometimes high. Especially when electrolyzing anode copper with high antimony and bismuth content, the conventional electrolysis method for purifying the electrolyte cannot meet the process conditions of electrolysis in the electrolyte. The antimony and bismuth content in the electrolyte is high, which seriously affects the quality of cathode copper. There are also ion exchange, extraction, chemical precipitation, chemical reduction and other methods in the copper electrolysis purification process, but these methods are rarely used in practice. The invention patent CN201110088216.4 discloses a method for purifying copper electrolyte by regulating valence state. The method proposes introducing sulfur dioxide into a part of the copper electrolyte to reduce pentavalent As and pentavalent Sb in the copper electrolyte to trivalent As and trivalent Sb; adding an oxidant to another part of the copper electrolyte to oxidize trivalent As and trivalent Sb in the copper electrolyte to pentavalent As and pentavalent Sb; then mixing the reduced copper electrolyte and the oxidized copper electrolyte to adjust the valence state ratio of As and Sb in the copper electrolyte, removing copper, arsenic, antimony and bismuth in the electrolyte through concentration and crystallization, so that the electrolyte is purified.

[0003] When using electrolytic method to purify copper electrolyte, there are not only disadvantages of high energy consumption and precipitation of highly toxic arsenic hydrogen gas at the end of electrolytic process; at the same time, there are also problems such as excessive removal of antimony and bismuth, which requires a large amount of electrolyte to enter the purification process for electrolytic process, causing copper acid imbalance in the system, and copper sulfate needs to be purchased for liquid preparation to ensure the balance of copper ions in the electrolyte. A part of the excess acid needs to be extracted and discharged to ensure the acid in the electrolyte, and the production costs such as electricity costs increase significantly. The advantage of ion exchange method is that the composition of copper electrolyte does not change after treatment, the resin can be recycled, the process is simple, and the operation is easy; but its disadvantage is that the resin exchange capacity is limited, and the Cl- generated by the analysis pollutes the electrolyte. The extraction method has strong extraction of As, weak extraction of antimony and bismuth, long extraction process, large loss of extractant, and high cost. In the method for purifying copper electrolyte by regulating valence state disclosed in CN 201110088216.4, not only sulfur dioxide needs to be introduced into the copper electrolyte, but also an oxidant needs to be added to part of the electrolyte. The process is relatively complicated and the operation is cumbersome. At the same time, sulfur dioxide is a hazardous chemical and there is a risk of leakage. 3. Summary of the invention:

[0004] The technical problem to be solved by the present invention is: according to the problems of high energy consumption, complicated operation and high cost in the prior art of reducing the antimony and bismuth content in copper electrolyte, the present invention provides a method for effectively reducing the antimony and bismuth content in copper electrolyte. The method of the present invention has the advantages of convenient operation, low investment, low energy consumption and low cost.

[0005] In order to solve the above problems, the technical solution adopted by the present invention is:

[0006] The present invention provides a method for reducing the antimony and bismuth content in a copper electrolyte, the method comprising the following steps:

[0007] 1) Detect and analyze the arsenic, antimony and bismuth content of each batch of copper anode plates loaded into the copper electrolytic cell;

[0008] 2) Under the condition that the arsenic content in the electrolyte is 8-20 g / L, the antimony and bismuth contents in the copper anode plates are calculated, and the number of electrolytic cells to be converted into electrolytic cells is determined by calculation, and the copper anode plates in the electrolytic cells to be converted are lifted out, and inert anode plates are installed, so that the electrolytic cells are converted into electrolytic cells;

[0009] 3) When the electrolytic cell is powered on, the flow rate of the circulating electrolyte in the electrolytic cell is controlled to convert the pentavalent arsenic in the copper electrolyte into trivalent arsenic. Through the co-precipitation mechanism of trivalent arsenic, antimony and bismuth, most of the antimony and bismuth enter the copper anode mud, thereby reducing the content of antimony and bismuth in the copper electrolyte to meet the requirements.

[0010] According to the above method for reducing the antimony and bismuth content in copper electrolyte, in step 1), the copper anode plate loaded into the copper electrolytic cell has an arsenic content of 0.1-0.4%, an antimony content of 0.01-0.2%, and a bismuth content of 0.02-0.2%.

[0011] According to the above method for reducing the antimony and bismuth content in the copper electrolyte, the calculation described in step 2) is performed according to the antimony and bismuth content in the copper anode plate, and the number of electrolytic cells to be changed into electrowinning cells is determined by calculation. The specific calculation method is: taking 100 electrolytic cells as the benchmark, for every 0.1% increase in the antimony content in the copper anode plate, the number of electrowinning cells to be increased is 0.8 cells; for every 0.1% increase in the bismuth content in the copper anode plate, the number of electrowinning cells to be increased is 0.4 cells.

[0012] According to the above method for reducing the antimony and bismuth content in copper electrolyte, when the electrolytic cell is changed to an electrowinning cell in step 2), only the anode plate mode of the electrolytic cell is changed, and the current of the electrowinning cell is not changed, which is the same as the current of a normal electrolytic cell.

[0013] According to the above method for reducing the antimony and bismuth content in copper electrolyte, the material of the inert anode plate in step 2) is lead-calcium alloy, lead-antimony alloy or lead-arsenic alloy.

[0014] According to the above method for reducing the antimony and bismuth content in copper electrolyte, when controlling the flow rate of circulating electrolyte in the electrolytic cell in step 3), an electrolyte circulation amount detection device is added to the electrolytic cell.

[0015] According to the above method for reducing the antimony and bismuth content in copper electrolyte, in step 3), the flow rate of the circulating electrolyte in the electrolytic cell is controlled to be 7 to 40 L / min.

[0016] According to the above method for reducing the antimony and bismuth contents in the copper electrolyte, in step 3), the antimony and bismuth contents in the copper electrolyte are reduced, and at this time, the antimony content in the copper electrolyte is ≤0.5 g / L and the bismuth content is ≤0.8 g / L.

[0017] The process of the technical solution of the present invention is as follows: during the electrolytic refining process, arsenic in the anode plate mainly enters the electrolyte in the form of trivalent arsenic. During the circulation of the electrolyte, most of the arsenic in the electrolyte is oxidized to pentavalent arsenic, and the pentavalent arsenic reaches more than 95%. According to the calculation that 80% of the arsenic enters the electrolyte, a small amount of copper anode plates in the electrolytic cell are lifted out and inert anode plates are loaded. The anode plate mode in the copper electrolytic cell is changed, and the electrolytic cell is changed into an electrolytic cell. Under the condition that the electrolytic cell is powered on, the flow rate of the circulating electrolyte in the electrolytic cell is controlled so that the arsenic concentration in the electrolytic cell reaches arsenic. The concentration of the potential at which pentavalent arsenic is converted into trivalent arsenic by the main electrode reaction is higher than the concentration of the potential at which trivalent arsenic is converted into elemental arsenic. Then, the number of electrolytic cells changed into electrowinning cells is determined according to the arsenic content. The pentavalent arsenic in the copper electrolyte is converted into trivalent arsenic through the electrowinning mode. The electrolyte continuously converted into trivalent arsenic utilizes the co-precipitation mechanism of trivalent arsenic, antimony and bismuth in the circulation process to achieve the self-purification function of the copper electrolyte, so that more than 70% of antimony and bismuth enter the copper anode mud, meeting the content requirements of antimony ≤0.5g / L and bismuth ≤0.8g / L in the copper electrolyte.

[0018] The positive beneficial effects of the present invention are:

[0019] 1. The technical solution of the present invention directly performs electrolyte self-purification in the electrolysis system, reducing the amount of copper electrolyte purification, thereby reducing energy consumption and saving costs.

[0020] 2. The technical solution of the present invention controls the flow rate of the electrolyte to ensure the potential of pentavalent arsenic to be converted into trivalent arsenic, thereby avoiding the generation of elemental arsenic. At the same time, it also eliminates the disadvantage of the precipitation of highly toxic arsine hydrogen gas at the end of the electrolysis, and has high safety.

[0021] 3. According to the technical solution of the present invention, during the electrolyte self-purification process, arsenic, antimony and bismuth enter the copper anode mud, and no black copper mud with high arsenic, antimony and bismuth content is produced, thereby reducing the accumulation of arsenic, antimony and bismuth in the copper smelting system; there is no need to increase other equipment costs, and only the copper anode plate needs to be lifted out and replaced with an inert anode plate, with low investment.

[0022] 4. The technical solution of the present invention does not need to change the current of the electrolytic cell, disconnect the electrolytic cell from other electrolytic cells, or add an electrolyte circulation pump during the regulation process. It only needs to adjust the opening of the electrolyte circulation valve of the single electrolytic cell, which is simple to operate.

[0023] In summary, the method of the present invention has the advantages of convenient operation, low investment, low energy consumption and low cost. 4. Specific implementation methods:

[0024] The present invention is further described below in conjunction with embodiments, but the protection scope of the technical solution of the present invention is not limited thereto.

[0025] In the following embodiments, the number of electrolytic cells to be changed to electrolytic cells is determined based on the antimony and bismuth contents in the copper anode plates. The specific calculation method is as follows: taking 100 electrolytic cells as a benchmark, the number of electrolytic cells to be increased by 0.8 cells for every 0.1% increase in the antimony content in the copper anode plates; the number of electrolytic cells to be increased by 0.4 cells for every 0.1% increase in the bismuth content in the copper anode plates; step 2) when changing the electrolytic cell to the electrolytic cell, only the anode plate mode of the electrolytic cell is changed, and the current of the electrolytic cell is not changed, which is the same as the current of the normal electrolytic cell; when controlling the flow rate of the circulating electrolyte in the electrolytic cell, an electrolyte circulation amount detection device of the electrolytic cell is added.

[0026] Embodiment 1:

[0027] The method for reducing the antimony and bismuth content in a copper electrolyte of the present invention comprises the following detailed steps:

[0028] 1) Taking 100,000 tons / year of electrolytic copper, 400 electrolytic cells, and 54 copper anode plates (380 kg / piece) in each cell as an example, after testing, the arsenic, antimony, and bismuth contents of the copper anode plates loaded in the copper electrolytic cells are 0.38%, 0.12%, and 0.20%, respectively;

[0029] 2) Under the condition that the electrolyte contains 40 g / L copper and 10 g / L arsenic, according to the above-mentioned method of calculating the number of electrolytic cells to be converted into electrowinning cells based on the antimony and bismuth contents in the copper anode plates, when the current is 14000 A / h, 7 of the electrolytic cells need to be converted into electrowinning cells, the copper anode plates in the electrolytic cells to be converted are lifted out, and inert anode plates made of lead-calcium alloy are loaded, and the electrolytic cells are converted into electrowinning cells;

[0030] 3) When the electrolytic cell is powered on, the flow rate of the circulating electrolyte in the electrolytic cell is controlled to be 40 L / min, so that the pentavalent arsenic in the copper electrolyte is converted into trivalent arsenic, and most of the antimony and bismuth enter the copper anode mud through the co-precipitation mechanism of trivalent arsenic and antimony and bismuth, thereby reducing the content of antimony and bismuth in the copper electrolyte to meet the requirements; after purification, the antimony in the copper electrolyte is 0.38 g / L and the bismuth is ≤0.66 g / L.

[0031] Embodiment 2:

[0032] The method for reducing the antimony and bismuth content in a copper electrolyte of the present invention comprises the following detailed steps:

[0033] 1) Taking 150,000 tons / year of electrolytic copper, 600 electrolytic cells, and 54 copper anode plates (380 kg / piece) in each cell as an example, after testing, the arsenic, antimony, and bismuth contents of the copper anode plates loaded in the copper electrolytic cells are 0.36%, 0.15%, and 0.13%, respectively;

[0034] 2) Under the condition that the electrolyte contains 40 g / L copper and 10 g / L arsenic, the number of electrolytic cells to be converted into electrowinning cells is calculated according to the above-mentioned calculation method for determining the number of electrolytic cells to be converted into electrowinning cells based on the antimony and bismuth contents in the copper anode plates. When the current is 30,000 A / h, 10 of the electrolytic cells need to be converted into electrowinning cells, the copper anode plates in the electrolytic cells to be converted are lifted out, and inert anode plates made of lead-calcium alloy are loaded, and the electrolytic cells are converted into electrowinning cells;

[0035] 3) When the electrolytic cell is powered on, the flow rate of the circulating electrolyte in the electrolytic cell is controlled at 35 L / min, so that the pentavalent arsenic in the copper electrolyte is converted into trivalent arsenic, and most of the antimony and bismuth enter the copper anode mud through the co-precipitation mechanism of trivalent arsenic, antimony and bismuth, thereby reducing the content of antimony and bismuth in the copper electrolyte to meet the requirements; after purification, the antimony content in the copper electrolyte is 0.36 g / L and the bismuth content is 0.59 g / L.

[0036] Embodiment 3:

[0037] The method for reducing the antimony and bismuth content in a copper electrolyte of the present invention comprises the following detailed steps:

[0038] 1) Taking 200,000 tons / year of electrolytic copper, 800 electrolytic cells, and 54 copper anode plates (380 kg / piece) in each cell as an example, after testing, the arsenic, antimony, and bismuth contents of the copper anode plates loaded in the copper electrolytic cells are 0.30%, 0.04%, and 0.09%, respectively;

[0039] 2) Under the condition that the electrolyte contains 45 g / L copper and 10 g / L arsenic, according to the above-mentioned method of calculating the number of electrolytic cells to be converted into electrowinning cells based on the antimony and bismuth contents in the copper anode plates, when the current is 20,000 A / h, 6 of the electrolytic cells need to be converted into electrowinning cells, the copper anode plates in the electrolytic cells to be converted are lifted out, and inert anode plates made of lead-calcium alloy are loaded, and the electrolytic cells are converted into electrowinning cells;

[0040] 3) When the electrolytic cell is powered on, the flow rate of the circulating electrolyte in the electrolytic cell is controlled to be 20 L / min, so that the pentavalent arsenic in the copper electrolyte is converted into trivalent arsenic. Through the co-precipitation mechanism of trivalent arsenic, antimony and bismuth, most of the antimony and bismuth enter the copper anode mud, thereby reducing the content of antimony and bismuth in the copper electrolyte to meet the requirements; after purification, the antimony content in the copper electrolyte is 0.31 g / L and the bismuth content is 0.50 g / L.

[0041] Embodiment 4:

[0042] The method for reducing the antimony and bismuth content in a copper electrolyte of the present invention comprises the following detailed steps:

[0043] 1) Taking 150,000 tons / year of electrolytic copper, 600 electrolytic cells, and 54 copper anode plates (380 kg / piece) in each cell as an example, after testing, the arsenic, antimony, and bismuth contents of the copper anode plates loaded in the copper electrolytic cells are 0.10%, 0.05%, and 0.02%, respectively;

[0044] 2) Under the condition that the electrolyte contains 45 g / L copper and 10 g / L arsenic, the number of electrolytic cells to be converted into electrowinning cells is calculated according to the above-mentioned calculation method for determining the number of electrolytic cells to be converted into electrowinning cells based on the antimony and bismuth contents in the copper anode plates. When the current is 30,000 A / h, three of the electrolytic cells need to be converted into electrowinning cells, the copper anode plates in the electrolytic cells to be converted are lifted out, and inert anode plates made of lead-antimony alloy are loaded, and the electrolytic cells are converted into electrowinning cells;

[0045] 3) When the electrolytic cell is powered on, the flow rate of the circulating electrolyte in the electrolytic cell is controlled to be 7L / min, so that the pentavalent arsenic in the copper electrolyte is converted into trivalent arsenic, and most of the antimony and bismuth enter the copper anode mud through the co-precipitation mechanism of trivalent arsenic and antimony and bismuth, thereby reducing the content of antimony and bismuth in the copper electrolyte to meet the requirements; after purification, the antimony content in the copper electrolyte is 0.28g / L and the bismuth content is 0.39g / L.

[0046] Embodiment 5:

[0047] The method for reducing the antimony and bismuth content in a copper electrolyte of the present invention comprises the following detailed steps:

[0048] 1) Taking 100,000 tons / year of electrolytic copper, 400 electrolytic cells, and 54 copper anode plates (380 kg / piece) in each cell as an example, after testing, the arsenic, antimony, and bismuth contents of the copper anode plates loaded in the copper electrolytic cells are 0.23%, 0.05%, and 0.06%, respectively;

[0049] 2) Under the condition that the electrolyte contains 45 g / L copper and 15 g / L arsenic, the number of electrolytic cells to be converted into electrowinning cells is calculated according to the above-mentioned calculation method for determining the number of electrolytic cells to be converted into electrowinning cells based on the antimony and bismuth contents in the copper anode plates. When the current is 20,000 A / h, three of the electrolytic cells need to be converted into electrowinning cells, the copper anode plates in the electrolytic cells to be converted are lifted out, and inert anode plates made of lead-antimony alloy are loaded, and the electrolytic cells are converted into electrowinning cells;

[0050] 3) When the electrolytic cell is powered on, the flow rate of the circulating electrolyte in the electrolytic cell is controlled to be 30 L / min, so that the pentavalent arsenic in the copper electrolyte is converted into trivalent arsenic. Through the co-precipitation mechanism of trivalent arsenic, antimony and bismuth, most of the antimony and bismuth enter the copper anode mud, thereby reducing the content of antimony and bismuth in the copper electrolyte to meet the requirements; after purification, the antimony content in the copper electrolyte is 0.29 g / L and the bismuth content is 0.44 g / L.

[0051] Embodiment 6:

[0052] The method for reducing the antimony and bismuth content in a copper electrolyte of the present invention comprises the following detailed steps:

[0053] 1) Taking 100,000 tons / year of electrolytic copper, 400 electrolytic cells, and 54 copper anode plates (380 kg / piece) in each cell as an example, after testing, the arsenic, antimony, and bismuth contents of the copper anode plates loaded in the copper electrolytic cells are 0.18%, 0.20%, and 0.14%, respectively;

[0054] 2) Under the condition that the electrolyte contains 45 g / L copper and 15 g / L arsenic, the number of electrolytic cells to be converted into electrolytic cells is calculated according to the above-mentioned calculation method for determining the number of electrolytic cells to be converted into electrolytic cells based on the antimony and bismuth contents in the copper anode plates. When the current is 20,000 A / h, 9 of the electrolytic cells need to be converted into electrolytic cells, the copper anode plates in the electrolytic cells to be converted are lifted out, and inert anode plates made of lead-antimony alloy are loaded, and the electrolytic cells are converted into electrolytic cells;

[0055] 3) When the electrolytic cell is powered on, the flow rate of the circulating electrolyte in the electrolytic cell is controlled to be 40 L / min, so that the pentavalent arsenic in the copper electrolyte is converted into trivalent arsenic, and most of the antimony and bismuth enter the copper anode mud through the co-precipitation mechanism of trivalent arsenic, antimony and bismuth, thereby reducing the content of antimony and bismuth in the copper electrolyte to meet the requirements; after purification, the antimony content in the copper electrolyte is 0.38 g / L and the bismuth content is 0.66 g / L.

Claims

1. A method for reducing the antimony and bismuth content in a copper electrolyte, characterized in that: The method comprises the following steps: 1) Detect and analyze the arsenic, antimony and bismuth content of each batch of copper anode plates loaded into the copper electrolytic cell; 2) Under the condition that the arsenic content in the electrolyte is 8-20 g / L, the antimony and bismuth contents in the copper anode plates are calculated, and the number of electrolytic cells to be converted into electrolytic cells is determined by calculation, and the copper anode plates in the electrolytic cells to be converted are lifted out, and inert anode plates are installed, so that the electrolytic cells are converted into electrolytic cells; 3) When the electrolytic cell is powered on, the flow rate of the circulating electrolyte in the electrolytic cell is controlled to convert the pentavalent arsenic in the copper electrolyte into trivalent arsenic. Through the co-precipitation mechanism of trivalent arsenic, antimony and bismuth, most of the antimony and bismuth enter the copper anode mud, thereby reducing the content of antimony and bismuth in the copper electrolyte to meet the requirements.

2. The method for reducing the antimony and bismuth content in a copper electrolyte according to claim 1, characterized in that: Step 1) The copper anode plate loaded into the copper electrolytic cell has an arsenic content of 0.1-0.4%, an antimony content of 0.01-0.2%, and a bismuth content of 0.02-0.2%.

3. The method for reducing the antimony and bismuth content in a copper electrolyte according to claim 1, characterized in that: According to the antimony and bismuth contents in the copper anode plate in step 2), the number of electrolytic cells to be changed into electrolytic cells is determined by calculation, and the specific calculation method is as follows: taking 100 electrolytic cells as the benchmark, for every 0.1% increase in the antimony content in the copper anode plate, the number of electrolytic cells to be increased is 0.8 cells; for every 0.1% increase in the bismuth content in the copper anode plate, the number of electrolytic cells to be increased is 0.4 cells.

4. The method for reducing the antimony and bismuth content in a copper electrolyte according to claim 1, characterized in that: When the electrolytic cell is changed to an electrolytic cell in step 2), only the anode plate mode of the electrolytic cell is changed, and the current of the electrolytic cell is not changed, which is the same as the current of a normal electrolytic cell.

5. The method for reducing the antimony and bismuth content in a copper electrolyte according to claim 1, characterized in that: The material of the inert anode plate in step 2) is lead-calcium alloy, lead-antimony alloy or lead-arsenic alloy.

6. The method for reducing the antimony and bismuth content in a copper electrolyte according to claim 1, characterized in that: When controlling the flow rate of the circulating electrolyte in the electrolytic cell in step 3), a device for detecting the circulating amount of the electrolyte in the electrolytic cell is added.

7. The method for reducing the antimony and bismuth content in a copper electrolyte according to claim 1, characterized in that: Step 3) Control the flow rate of the circulating electrolyte in the electrolytic cell to 7 to 40 L / min.

8. The method for reducing the antimony and bismuth content in a copper electrolyte according to claim 1, characterized in that: In step 3), the contents of antimony and bismuth in the copper electrolyte are reduced. At this time, the antimony content in the copper electrolyte is ≤0.5 g / L, and the bismuth content is ≤0.8 g / L.