Recovery and Reuse of Spent ITO Targets through Electrochemical Techniques

Abstract

Indium is a strategically scarce metal with excellent conductivity and light transmittance that is widely used to prepare ITO targets. In this work, an electrolysis method was exploited to recover and reuse spent ITO (s-ITO) targets to provide a novel way to recycle valuable resources. The electrochemical behaviors of indium tin oxide were studied first by cyclic voltammetry in CaCl2 at 850 °C. A reduction peak corresponding to the simultaneous reduction of indium tin oxide was found at −0.5 V vs Pt. Then, indium-tin alloy was recovered by electrolysis of s-ITO particles in CaCl2 at −2.8 V and 850 °C. The mass ratio of In and Sn in the alloy obtained by electrolysis is almost the same as that in the initial s-ITO before electrolysis. In addition, oxide composite powders were obtained by electrolysis of the alloy in NH4Cl aqueous solution, which can be used to synthesize ITO targets. The particle size of the composite powders was between 20 nm and 60 nm, and the distribution of each element was uniform.