Comprehensive recovery of Fe, Zn, Ag and In from high iron-bearing zinc calcine

Abstract

A beneficiation-metallurgy combination process is developed to recover Zn, Fe and to enrich In, Ag from high iron-bearing zinc calcine based on our former researches. In gaseous reductive roasting process, the roasting conditions were tested by magnetic separation of roasted product. It is found that the \({V_{CO}}\left( {{{{P_{CO}}} \mathord{\left/ {\vphantom {{{P_{CO}}} {{P_{CO + C{O_2}}}}}} \right. \kern-\nulldelimiterspace} {{P_{CO + C{O_2}}}}}} \right)\) in roasting atmosphere should be maintained below 30% to avoid the generation of zinc iron solid solution (Fe0.85-x Zn x O), which can bring a decrease of iron recovery in magnetic separation. After roasting, acid leaching and multistage magnetic separation are carried out for the recovery of Zn, Fe and enrichment of Ag and In. About 90% of zinc is extracted and 83% of iron is recovered in the whole process. The Ag mainly enters the tailings with a recovery of 76%, the Ag grade increases from 0.12 g/t in raw materials to 1.18 g/t in the tailings. However, the In mainly enters the iron concentrations and the recovery reaches 86%. This process was proved to be technically feasible and may be a favorable option in the treatment of high iron-bearing zinc material with high Ag or In content.