Abstract: The invention relates to the treatment of purge solutions formed in the process of the extraction of zinc by electrolysis.According to the invention, the purge solution, which consists of a part of the purified solution rich in zinc sulfate, is subjected to electrodialysis in the presence of an anion exchange membrane so that a catholyte is formed which is depleted in zinc and in sulfate and which contains magnesium. The catholyte can then be precipitated by neutralization, after recovery of the remaining zinc.Application to the extraction of zinc from its ores.