A novel method for synchronous separation of In/Sn from waste indium tin oxide (ITO) target: In-situ regeneration of nano-ITO powder

Waste indium-tin-oxide (ITO) targets were not only hazardous e-waste, but also a secondary resource with great value of indium and tin. However, current hydro-/pyro-metallurgy extractive methods just focused on the separation of indium and tin, which were always with a long process flow and a high ratio of metal loss. In this study, a novel co-volatilizing process of In/Sn recovery from waste ITO was provided, and nano-ITO powder was in-situ synthesized under the two-stage controlled atmosphere. The effect of roasting parameters on co-volatilizing of In/Sn was investigated using thermodynamic analysis, XRD, SEM and TEM, as well as phase transformation and oxide crystallization process of nano-ITO. The results indicated that a critical factor was to selectively reduce ITO to In2O/SnO under a weak CO-CO2 atmosphere. In addition, gaseous In2O/SnO can be oxidized synchronously and crystallized well as nano-ITO powders with an average grain size of 45.6 nm. This work proposed a short process and high-value use method for waste ITO targets.