Extraction and separation of indium and copper from zinc residue leach liquor by solvent extraction

Solvent extraction and separation of indium and copper from zinc residue reductive leach liquor containing a high concentration of zinc (ca. 85 g/L) and iron (ca. 35 g/L) was studied. Di-(2-ethylhexyl) phosphoric acid (D2EHPA) and Acorga M5640 were used as extractants for indium and copper, respectively. Indium was preferentially extracted by 15%(v/v) D2EHPA with three-stage extraction using an aqueous/organic (A/O) phase ratio of 6/1. Indium was effectively stripped from the D2EHPA organic phase by 4 M HCl. Copper was subsequently extracted selectively from the indium-extracted solution using 15%(v/v) Acorga M5640 with three-stage extraction using an A/O phase ratio of 2/1. Copper in the loaded Acorga M5640 organic phase was stripped by a synthetic spent electrolyte solution containing 25 g/L Cu and 180 g/L H2SO4. Based on the experimental results, a flowsheet for the separation and recovery of indium and copper from the reductive leach solution was developed and tested. The results showed that 95.4% of indium and 95.5% of copper were extracted, and the measured separation factors beta(In/Cu), beta(In/Fe), beta(CuZn), and beta(CuFe) were 4979, 1975, 3719, 1719, and 2446, respectively. (C) 2015 Elsevier B.V. All rights reserved.