The relative efficiency of electrowinning indium from chloride electrolytes

Abstract The main characteristics of electrolytic reduction applied to indium recovery from aqueous chloride solutions were considered theoretically and examined experimentally. Also other media for comparison. Potentiodynamic examinations pointed out that electrolytes are superior sulphuric nitric acid-based ones efficient deposition. optimum conditions, allowing higher than 90% cathodic current efficiencies, determined by galvanostatic experiments. In contrast, similar sulphate could only yield lower 50% efficiencies because a stronger hydrogen evolution. results confirmed the findings potentiodynamic study. polarisation curves revealed major deposition process, implying electroactive 3+ ions. Coupled processes dynamic transformations complex species various rates simultaneous structure elemental composition the—relatively dense—cathodic deposits scanning electron microscopy energy-dispersive X-ray analysis. Various levelling agents also tested, gelatine (up concentration 1 g/dm 3 in electrolyte) was found grain refining. Graphical abstract