Ultrasonic-assisted electrochemical strategy for ITO scraps recovery through anodic dissolution

Recycling ITO scraps through a sono-electrochemical approach in ammonium salt solution at ambient temperature to obtain hydroxide powder based on the ITO anodic deconstruction mechanism. • The process simplifies the operation and provides possibilities for scaling up. • The difficulty of selecting anode materials in traditional electrolysis is no longer an issue. • The process achieved closed-loop utilization of the rare precious metal indium. • Various products (oxides or alloys) can be obtained through this process. The conversion of ITO scraps into oxide powders that can be employed to prepare targets is integral to the closed-loop utilization of scare metal indium. Herein, we present a novel route for electrochemical coupled ultrasonic recovery of ITO scraps, which averts the consumption of strong acids, alkalis and carbon containing reducing agents in traditional hydrometallurgical or pyrometallurgical recovery processes. In an ammonium salt solution, the ITO anode dissolves under the action of electrons: oxygen ions are oxidized, while metal ions are leached out, and then combines with hydroxide ions in the solution to form flocculent precipitates, which is attributed to the extremely low solubility product of indium hydroxide and tin hydroxide. The ultrasonic field can promote the mass transfer between the electrode and electrolyte interface, thereby accelerating the reaction process regulating the morphology and size of the product. After calcination, the precipitates become uniformly mixed nano-scale oxide powders with dimensions that meet the requirements for target preparation. The recycling strategy, with its green, straightforward operation, and feasible for scale-up, suggests potential industrial uses for recovering ITO scraps.