Clean and efficient recovery of gallium–indium alloy from gallium-based liquid metal waste using a two-stage vacuum distillation method

Gallium (Ga) and indium (In) are rare metals widely used in the high-tech industry. Gallium-based liquid metal (G-LM) waste is produced during the preparation of liquid metal and related products. G-LM waste is a potential source of gallium and indium. In this study, the saturated vapor pressure, separation coefficient, and gas–liquid equilibrium phase diagram were determined using the simplified molecular interaction volume model. A two-stage vacuum distillation method was used to recover Ga–In alloy from G-LM waste. First, low-temperature vacuum distillation was used to recover 98.23 % of Zn under optimal conditions (1–5 Pa; 773 K; 60 min). Then, the Ga–In alloy was recovered through high-temperature vacuum distillation. Under the optimal conditions (1–5 Pa; 1523 K; 120 min), the recovery rates of gallium and indium were 85.14 and 95.23 %, and the content of Ga–In alloy in the product was 99.46 %. Compared with the traditional hydrometallurgical process for recovering gallium and indium, this process generates no exhaust gas or waste. In addition, this new method is simple, efficient, clean, and pollution-free. Overall, this new method for recovering Ga–In alloy provides a new avenue for comprehensively utilizing G-LM waste.