Novel process for comprehensive utilization of iron concentrate recovered from zinc kiln slag

Abstract

A novel process, including hydrochloric acid leaching, iron powder replacing, sulphide precipitation and spray pyrolysis, was proposed to treat iron concentrate recovered from zinc kiln slag for comprehensive utilization. Treated by solution of 6 mol/L hydrochloric acid at 60 ℃, the leaching rates of Ag, Pb, Cu, Fe and Zn reach 99.95%, 99.34%, 95.07%, 89.44% and 57.92%, respectively. More than 98% Cu and Ag are recovered from the leach liquor when stoichiometric ratio of iron powder is 1.25 times of the theoretical value. More than 96% Pb and Zn is removed with three times of theoretical consumption of FeS, and the concentration of impurities of the final solution is less than 500 mg/L. Fe2O3 powder, which is spherical with mean size of 12 um and purity of 99%, is prepared with final solution at above 700 ℃. By this process, not only the metal values can be recovered effectively, but also the iron resources of zinc kiln slag can be converted into Fe2O3 with high purity, thus, the comprehensive utilization of iron concentrate recovered from zinc kiln slag can be realized.