Abstract
During the hydrometallurgical extraction process of zinc, the elimination of chloride ions from the electrolyte is an important issue, because the contamination of the anode by chloride ion promotes the dissolution of Pb from the anode and raises the Pb content in the zinc cathode.
In this study, two fundamental investigations were carried out. One involved the anodic oxidation behaviors of zinc sulfate solutions, while the other was concerned with the elimination process of chlorides ions as precipitations by adding copper powder to the solution.
The concentration of chloride ion was reduced to about 50 ppm by electrolytic oxidation using Pb-alloy anodes (Pb-Ag and Pb-Ag-Ca). However, the rate of decrease in the chloride ion concentration was not very rapid when using the Pb-alloy anodes compared when using catalytic activated anodes (Pt, Ti/RuO2).
Chloride ions can be removed as CuCl by the addition of copper powder. However, it was found that the presence of a large amount of copper ion [Cu2+] in the solution was required for the more effective elimination of the chloride ions.
