Recovery of Valuable Metals from Zinc Plant Residues by Two-Stage Selective Atmospheric Leaching Process

Abstract

A hydrometallurgical process was used for selectively extraction of valuable metals from zinc plant residues. The process includes the following two steps. (1) The zinc plant residue is treated by sulfuric acid atmospheric leaching process with KMnO4 as oxidatant to selectively dissolve zinc while leaving most (above 98 pct) of indium and germandium in the iron residues. (2) The iron residues are treated by acidic atmospheric leaching process with NaClO3 as oxidant to dissolve indium and germanium. The valuable metals of indium and germanium in the second leaching solution can be reclaimed by further treatment. The optimum operating parameters of the first stage and the second stage were established by conditional tests. The experimental data indicated that under the conditions employed the zinc extraction in the first stage was above 95%, and the leaching percentage of indium and germanium in the second stage reached 91.6% and 90.7%, respectively.