The Efficient Electrolytic Deposition of Indium from Aqueous Chloride Media

The main characteristics of electrolytic reduction applied for indium recovery from aqueous chloride solutions were considered theoretically and examined experimentally. In comparison, also sulphuric and other media were examined. Potentiodynamic examinations pointed out that chloride electrolytes are superior to sulphuric, nitric and methanesulphonic acid ones for efficient In deposition. The optimum conditions allowing higher than 90% cathodic current efficiencies, were determined by galvanostatic experiments, confirming the findings of the potentiodynamic study. In contrast, similar sulphate electrolytes could only yield lower than 50% efficiencies, mainly because of stronger hydrogen evolution and the potentially slower transformations of the complex ions. The structure of the – relatively dense - cathodic deposit was examined. Various levelling agents were also tested, and gelatine was found efficient in preventing the formation of dendrites.