Abstract:In order to solve the problem that high concentration hydrochloric acid stripping is needed in the traditional solvent extraction process of zinc sulfate solution in zinc hydrometallurgy to recover indium, and chloride ions are entrapped in the poor organic phase after stripping, which endangers zinc hydrometallurgy. In this paper, P204-TOPO mixed extraction system was used to selectively extract indium from indium-containing leaching solution, and the indium-loaded organic phase was stripped by sulfuric acid to realize the recovery of indium in chlorine-free system. It was found that the extraction process of indium in the mixed system belongs to cation exchange, and the association of TOPO and P204 weakens the stability of the extraction complex formed by P204 and indium ions, which was beneficial to improve its stripping performance. The effects of single factor conditions such as extractant concentration, reaction time, sulfuric acid concentration and temperature on the extraction of indium were studied. The results showed that the extraction efficiency of indium was 97.24%, the extraction ratio of zinc and iron was low than 5% under the conditions of the mixture of 10%P204-4%TOPO-86% sulfonated kerosene, an O/A phase ratio of 1/1, sulfuric acid concentration of 20g/L at 25°C for 5 min.Using 6 mol/L sulfuric acid as stripping agent, under the conditions of O/A ratio of 1/1 and stripping time of 15 min, the stripping rates of indium, zinc and iron are 99.80%, 93.53% and 95.66%, respectively. The lean organic phase does not contain chloride ions, and can be recycled after scrubbing.