Abstract:Taking zinc leaching residue of conventional zinc hydrometallurgy process as research object, leaching behavior of zinc, copper and indium in zinc leaching residue and decrement of zinc leaching residue were comparative studied in the process of atmospheric and pressure system. The results show that under the condition of atmospheric acid leaching, the residue amount can be reduced by more than 65%, zinc content in residue can be reduced to about 3%, and leaching efficiency of zinc, copper and indium are all above 91%. The residue amount can be reduced by more than 40%, and zinc content in residue can be below 2% in the process of pressure acid leaching. Leaching efficiency of zinc and copper can reach about 95%, but leaching efficiency of indium is only about 70%, which is relatively low. The vast majority of iron in zinc leaching residue is leached during atmospheric acid leaching, which is conducive to leaching of indium. A large number of iron in zinc leaching residue remains in the form of plumbojarosite during pressure acid leaching process, which hinders leaching of indium. Iron content in atmospheric leachate is higher, reaching more than 25 g/L, while iron content in pressurized leachate is 2 g/L below, which is beneficial to recovery of copper and indium in subsequent leachate. The amount of atmospheric leaching residue is small, which is beneficial to enrichment of lead and silver in the residue, and can be sold separately. Due to iron precipitation into residue during pressure leaching, resulting in low enrichment ratio of lead and silver in the residue, it is suitable for lead-zinc joint enterprise back to lead smelting furnace.