Effect of phosphate on indium recovery with pyrophosphate from industrial jarosite in alkaline medium

Abstract Jarosite is a by-product generated in the zinc hydrometallurgical process due to its several advantages, including the selective precipitation of iron in a stable form, the recovery of sulfur, and the extraction of zinc. Hence, it lacks direct commercial value; it has been studied for its metallic content, including silver, gold, and indium; however, Jarosite is difficult to process due to its leaching-resistant nature. This study examines the effects of phosphate concentration and pH on indium recovery with jarosite pyrophosphate in an alkaline medium. Phosphate reduces pH variations, preventing iron solubilization and decreasing reagent consumption. At pH 8, indium recovery reaches a recovery of up to 98% with 0.4 M in the presence of 0.13 M pyrophosphate with a low iron content in solution of around 0.7%. The presence of PO 4 3− promotes the stability of the system, with low iron and copper concentrations of 105.7 and 66.7 ppm, respectively. Graphical abstract