Removal and Recovery of Indium from ITO Coated Glass and Scraps Using Molten Salt Electrolysis

Abstract

Indium is an important strategic resource due to the scarcity for the metal. In the present study, molten salt electrolysis is used to reduce indium from ITO coated glass and scraps in order to seek a new way to recycle the value resource. The electrochemical behavior of indium and tin oxides was studied by cyclic voltammetry at 450°C in molten LiCl-KCl. The reduction peaks were observed in the cathodic scan for In2O3 and SnO2. Constant voltage electrolysis was performed at 1.7 V and 450°C for ITO. The deposits between ITO layer and the cathode were collected and analyzed by XRD. The reduction reaction occurred at the interface of the oxide pellets and the cathode. Metallic indium and Sn-In alloys were detected after electrolysis. The ITO covered glass was reduced by electrochemical method in molten LiCl-KCl at 450°C under argon with Mo wire contacting electrode. The findings, together with SEM and EDX analyses, confirmed ITO layer was removed from the glass surface.