JPS6025510B2 - Electrowinning of copper and tin - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for electrowinning copper and tin from an acidic aqueous solution in which copper ions and tin ions coexist.

As is well known, in order to regenerate the tin-plated copper wire shoulder and use it as a steel material, the tin-plated copper wire layer is usually electrolyzed in dilute sulfuric acid to remove tin. In order to circulate and reuse the electrolyte, it is necessary to regenerate the electrolyte by electrowinning the steel ions and tin ions eluted into the electrolyte.

In particular, as mentioned above, if a large amount of tin accumulates in the acidic electrolyte during the electrolytic detining process, metastannic acid will be generated and this will firmly adhere to the steel wire, significantly reducing the detining efficiency. Therefore, it is necessary to electrolytically extract tin ions from the electrolyte before a large amount of tin ions accumulates, and in this sense, extracting tin from the electrolyte in electrolytic detining is an important process. There is. In addition, when regenerating bronze pickling solution, it is necessary to electrolytically extract copper ions and tin ions from the pickling solution, and dilute sulfuric acid electrolysis is also required to recover tin from solder shoulders including copper wire terminals. Even when electrolyzing with a liquid, it is necessary to electrolytically extract tin ions and copper ions from the electrolyte in order to regenerate the electrolyte. By the way, as mentioned above, as a method for electrolytically extracting tin and copper from an acidic aqueous solution in which copper ions and tin ions coexist, there is a conventional method in which the acidic aqueous solution in which both the above ions coexist is directly electrolyzed using a non-falling anode. However, in this method, copper ions are relatively easily deposited and can be successfully collected, but tin ions are relatively difficult to electrodeposit, and therefore, there is a problem in that the collection rate of tin is low.

The inventors of this invention have repeatedly researched the above-mentioned problem and found that if an electrolyte containing chlorine ions is added to an acidic aqueous solution in which copper ions and tin ions coexist to make the chlorine ions coexist, the electrowinning rate of tin can be increased. It was found that the bull wind was improved.

This invention was made based on this knowledge,
The method is characterized in that copper and tin are electrolytically extracted by electrolyzing an acidic aqueous solution in which copper ions and tin ions coexist with chlorine ions at a concentration of 0.03 to 30 ta'. The method of the present invention will be explained in more detail below.

Examples of the acidic aqueous solution that can be used in the method of the present invention include a sulfuric acid aqueous solution, a sulfamic acid aqueous solution, a borofluoric acid aqueous solution, and the like. In this invention, chlorine ions are made to coexist in the above-mentioned acidic aqueous solution in which copper ions and tin ions coexist. What is necessary is to add and mix an electrolyte having the following. When hydrochloric acid is used as the electrolyte to be added here, it has the advantage that there is no risk of Na etc. accumulating even if it is repeatedly added, unlike when using common salt, and therefore hydrochloric acid is practically optimal. However, depending on the conditions of use, it is of course possible to use common salt. Further, the concentration of chlorine ions coexisting in the acidic aqueous solution is at least 0.03/so or more and 30/so or less. If it is less than 0.03 ta, the amount of chlorine ions is too small to improve the tin extraction rate, and if it exceeds 30 ta, precipitation of cuprous chloride or chlorine gas from the anode may occur. There is a problem in that the generation of bubbles increases and an overvoltage increase effect due to bubbles occurs.

In addition, within the above-mentioned range, a range of 2 to 49/or so is most desirable. Note that if constant potential electrolysis is performed during this electrolysis, a large amount of copper will be precipitated first, and then a large amount of tin will be precipitated, so that copper and tin can be roughly distinguished and collected.

Next, a comparative example using a conventional method and an example using the method of the present invention will be described. Comparative Example: Electrowinning by electrolyzing an aqueous solution containing CuS04 with a copper content of 10 m/m, SnS04 with a tin concentration of 10 m/m, and S04 with a ratio of 150 m/m concentration at 4000 °C. I did it.

Here, a platinum-plated titanium plate was used as the anode, and a stainless steel plate was used as the cathode. The surface area of the submerged grooves of both electrodes is 100 mm each, and the current applied is 20 A DC.
It is. Since the deposits deposited on the cathode were flocculent and easily fell, electrolysis was interrupted several times during the process and the deposits were collected. Chemical analysis of the metal powder collected from the start of energization until a total of 60 minutes had passed revealed that copper was 8.09 mm and tin was 3.09 mm.
It contained 57 ta. When electrolysis continued for another 60 minutes, the new electrodeposit was 0.70 copper and 0.44 tin, and the total amount collected in 12 minutes from the start of electrolysis was 879 copper.
In the evening, it was tin 4.01 evening. Example 1 After adding 35% concentration of hydrochloric acid 10' to the same electrolytic solution used in the comparative example, electrowinning was performed under the same conditions as in the comparative example. During the first 60 minutes, 8.91 units of copper and 6.60 units of tin were collected, and in the next 60 minutes, 0.57 units of copper and 1.72 units of tin were collected.

Therefore, the total amount collected for 120 minutes was 9.48 copper and 8.32 tin. Example 2 Salt was added to the same electrolytic solution as that used in the comparative example.
After adding it, electrolytic extraction was carried out under the same conditions as in the comparative example, and in the first 60 minutes after the start of electrolysis, 8.90 copper,
6.55 min of tin was extracted and in the next 60 minutes 0.55 min of copper was extracted.
Evening: 1.75 tons of tin was collected.

Therefore, the total amount collected for 120 minutes was 9.45 copper and 8.30 tin. As is clear from the above examples, when hydrochloric acid or common salt is added to an acidic aqueous solution in which steel ions and tin ions coexist, the extraction rate of tin is significantly improved compared to when no addition is made. Copper extraction efficiency also increases slightly. Since hydrochloric acid and common salt are electrolytes each containing chlorine ions, it is clear that the extraction efficiency of tin and copper was improved by allowing chlorine ions to coexist in the acidic aqueous solution. Therefore, according to the method of the present invention, when tin and copper are electrolytically extracted from an acidic aqueous solution in which tin ions and copper ions coexist, the extraction rate of tin and copper, especially the extraction rate of tin, which has conventionally been low, can be improved. It can be greatly improved, and it can be used to recycle the electrolyte used for electrolytic detinning of tin-plated copper wires, to recover tin by electrolyzing solder shoulders including copper wire terminals, or to treat bronze oxidation. It is useful when applied to washing liquid regeneration treatment, etc.

Claims (1)

[Claims] 1 Copper and tin are removed from the acidic aqueous solution by electrolyzing the acidic aqueous solution by allowing chlorine ions to coexist in an acidic aqueous solution containing copper ions and tin ions so that the concentration thereof is 0.03 g/l or more and 30 g/l or less. An electrowinning method characterized by electrowinning.