High-efficiency recovery technology of indium from waste LCD panels with ionic liquid

Waste liquid crystal display (LCD) panels containing indium tin oxide (ITO) conductive films are important secondary resources for indium recovery. However, conventional inorganic-acid leaching processes usually cause severe equipment corrosion and secondary pollution. In this study, a mild and efficient leaching system using the acidic ionic liquid (IL) [Bmim]HSO 4 was developed for recovering indium from waste LCD panels. Complete indium leaching was achieved under the optimized conditions of 5% IL, 5 g·L −1 ITO glass powder, 70 °C, and 180 min. The leaching process selectively disrupted the ITO structure and promoting indium dissolution under mild conditions, while causing no severe corrosion of the glass substrate. Reusability tests showed that the ionic liquid regenerated by acid-base treatment maintained excellent leaching performance, confirming its good recyclability. Kinetic analysis indicated that the initial leaching stage was jointly controlled by internal diffusion and chemical reaction, with an apparent activation energy of 30.53 kJ/mol, whereas the later stage was controlled by internal diffusion, with an apparent activation energy of 17.25 kJ/mol. This work provides a green and effective route for indium recovery from waste LCDs and offers both technical guidance and theoretical support for the industrial recycling of indium-containing electronic waste.