Systematic thermodynamic and experimental studies for recovering indium and tin from indium tin oxide waste target with hydrogen

Abstract

Resource utilization of waste indium tin oxide (ITO) can not only avoid the hazards of electronic waste, but also realize the recycling of dispersed metal indium (In). However, the current carbon thermal reduction process has the problems of high energy consumption and large carbon emissions. In this study, the feasibility and specific advantages of hydrogen reduction of waste ITO were explored by using high energy density and non-polluting H2 as reducing agent. The reduction process was thermodynamically analyzed by isothermal equation and molecular interaction volume model (MIVM), and the thermodynamic analysis results were verified by systematic experimental study. Experimental results showed that the reduction ratio of waste ITO can reach 99.43% under optimal conditions of 1173 K, 120 min, and 0.3 mol/L H2 flow rate, which indicated that the reduction process is feasible and efficient. Compared with vacuum carbothermal reduction process, hydrogen reduction process can reduce carbon emissions from the source, and theoretical energy consumption can be reduced by 70.12%. This work proposes a new method for recycling waste ITO that can reduce energy consumption and carbon emissions, providing further opportunities for the recycling of indium resources and the green economy of the electronics industry.