JPH055902B2 - - Google Patents

Description

[Detailed description of the invention]

(a) Technical field The present invention provides a method for purifying a copper electrolyte that can easily remove impurities such as antimony, bismuth, and arsenic from the copper electrolyte in order to improve the quality of electrolytic copper in the copper electrolysis process. It is related to. (b) Prior art In the electrolytic refining of copper, impurities such as antimony, bismuth, arsenic, etc. contained in the raw copper plate that serves as the anode are partially eluted into the copper electrolyte as the electrolysis progresses. However, if their concentration in the electrolytic solution increases, the quality of electrolytic copper will deteriorate. Therefore, in order to improve the quality of electrolytic copper,
A liquid purification process to remove these impurities from the copper electrolyte is essential. Therefore, the conventional method for removing impurities such as antimony, bismuth, and arsenic from this copper electrolyte is decopper removal, in which the copper electrolyte is electrolyzed with an insoluble anode, and these impurities are electrolytically extracted together with the copper in the copper electrolyte. Electrolytic methods and sulfide precipitation methods are used in which hydrogen sulfide gas is blown into a copper electrolyte to remove these impurities along with copper as sulfide precipitates. However, these methods remove impurities such as antimony, bismuth, and arsenic in the copper electrolyte along with the copper, so metals, slime, and sulfide precipitates electrodeposited by copper removal electrolysis must be removed before copper recovery. There is a drawback that repeated recovery treatments are required in the process, which complicates the process and increases costs. In addition, there is also the activated carbon method, which brings a copper electrolyte into contact with activated carbon to remove impurities in the electrolyte, and the solvent extraction method, which brings a copper electrolyte into contact with an organic solvent to extract and remove impurities such as antimony, bismuth, and arsenic. Yes, but
These methods may absorb organic substances such as glue, which are added to the electrolytic solution to improve the quality of electrolytic copper and improve electrolytic efficiency, or some of the solvent may dissolve in the electrolytic solution and cause the solvent to dissolve. There are drawbacks such as a loss in the amount of water and a negative effect on electrolysis. (C) Disclosure of the Invention The present invention eliminates the need to repeat the solid-liquid separation of impurities from the copper electrolyte in the previous step to recover the copper content, and also eliminates the need for organic additives such as glue in the copper electrolyte. To provide a method that can selectively separate and remove only impurities such as antimony, bismuth, arsenic, etc., without disturbing the balance of substances and without affecting the concentration of components such as copper, sulfuric acid, etc. . That is, the present invention has discovered that antimony, bismuth, and arsenic are preferentially separated by cooling the copper electrolyte, and that this effect is further promoted by oxidizing the copper electrolyte. be. Normally, in the operation of copper electrolytic refining, the electrolyte composition is 40 to 50 g of copper content/150 to 200 g of free sulfuric acid content/
, the electrolyte temperature is controlled at 50-60℃. This electrolytic solution is cooled to 45° C. or lower, preferably 20 to 40° C., to perform solid-liquid separation. For example, if the electrolyte is allowed to stand for 24 hours or more, preferably 48 hours or more, antimony, bismuth, and arsenic in the electrolyte are separated as white precipitates. In this case, almost no change is observed in the copper concentration and sulfuric acid concentration in the electrolyte. In addition, the copper electrolyte can be oxidized by adding an oxidizing agent such as potassium permanganate, manganese dioxide, hydrogen peroxide, air, oxygen gas, or ozone to the copper electrolyte, or by other oxidation methods. ℃ or less, preferably 20 to 40℃, to perform solid-liquid separation. for example
By allowing the mixture to stand for 24 hours or more, antimony, bismuth, and arsenic are removed as precipitates, and can be removed more effectively than by simply cooling. In this case as well, there is almost no change in the copper concentration and sulfuric acid concentration in the electrolyte. The solid content separated and removed from the copper electrolyte by this method has an antimony grade of 10 to 40%, a bismuth grade of 5 to 20%, and a copper grade of about 0.5 to 3.0%. It can be extracted from the copper electrolytic system without repeating the previous steps during copper smelting, such as a furnace or converter, and furthermore, it has high antimony and bismuth grades, so it can be used as a raw material for the production of antimony and bismuth. (d) Examples Example 1 A copper electrolyte at 60°C was taken into a glass container, and left standing in a thermostatic water bath set at 30°C for 72 hours. Table 1 shows the results of sampling and analyzing the electrolyte solution every 24 hours. Example 2 Copper electrolyte at 60°C was dispensed into a glass container and heated to 20°C.
It was left standing in a thermostatic water bath set at ℃ for 72 hours. Figure 2 shows the results of sampling and analyzing the electrolyte solution every 24 hours.

【table】

[Table] Example 3 Copper electrolyte at 60°C was taken into a glass beaker, 0.5g/potassium permanganate was added thereto, and the mixture was left standing in a thermostatic water bath set at 30°C for 72 hours. held. Table 3 shows the results of sampling and analyzing the electrolyte solution every 24 hours. Example 4 A copper electrolyte at 60°C was taken into a glass beaker, 2 ml of hydrogen peroxide was added thereto, and the mixture was left standing in a thermostatic water bath set at 30°C for 72 hours. Table 4 shows the results of sampling and analyzing the electrolyte solution every 24 hours.

【table】

[Table] An example of the precipitate obtained by the method of the present invention is Cu:
1.35%, As: 0.95%, Sb: 28.98%, Bi: 12.40%
Since the copper quality was low, there was no need to repeat the previous process. (E) Effects of the Invention According to the method of the present invention, copper electrolyte can be cooled simply or by oxidation, which is a simple and low-cost method, without affecting the copper and sulfuric acid concentrations in the electrolyte. Impurities such as antimony, bismuth, and arsenic can be effectively removed, and the separated precipitate contains almost no copper, so there is no need to repeat the previous process, and it can be used as a recovered raw material for antimony and bismuth. Can be reused.

Claims (1)

[Claims] 1 Add an oxidizing agent to a sulfuric acid acidic copper electrolyte containing antimony, bismuth, and arsenic as impurities to oxidize it, cool the electrolyte to a temperature of 45°C or less, preferably 20 to 40°C, and then perform solid-liquid separation. A method for purifying a copper electrolyte, comprising selectively separating and removing the impurities described above.