Study on the method of recovering and separating indium from residue containing indium

Abstract

A method of recovering indium from complex smelting residue containing indium was investigated. Indium was extracted by technique of low acid leaching and solvent extraction. The conditions of separating iron and indium were studied and the optimal conditions were determined. When the residue is two-class-countercurrent leached with 2 mol/L H₂SO₄ and 30–40 g/L NaCl at 100 °C, the leaching rate of indium is 80%. The extraction rate of indium is over 98% and that of iron is less than 5% after it is third-class-countercurrent extracted by P204, and when sulfonated kerosene is used as solvent, acidity in aqueous phase remains the same as that of leaching liquid, and phase is for 1:3. Using 2 mol/L HCl as back-extraction agent, with phase ratio being 5:1, by third-class-countercurrent back-extraction, the back-extraction rate of indium is over 99%, but that of iron is very low, which can meet the need of separating indium and iron.

Keywords

residue containing indium / indium / iron / recovery