Selective leaching of indium from spent LCD screens by siderophore desferrioxamine E

Abstract

Given the criticality of indium (In) in high-tech applications, spent LCD screens can represent a viable secondary In resource. In this work, an innovative and alternative technology to selectively leach In from spent LCD screens using a microbial chelating agent, desferrioxamine E (DFOE), was developed. Indium was concentrated from spent LCD screens by implementing an adapted pre-treatment procedure, allowing the isolation of an indium-rich glassy fraction. During leaching, the competition between aluminum (Al) and In for complexation with DFOE leads to the precipitation of In(OH)3 at low DFOE concentrations (12–240 µM). After adjusting the optimal conditions (fraction size: 0–36 μM, pH: 5.5, S/L ratio: 1 g/L, 25 °C), the In leaching yield reached 32%, ten times higher than Al over 90 days with 5 mM DFOE. Thus, achieving high In recovery is possible through i) prolonging leaching durations, ii) selective leaching, and iii) minimizing Al interference. This is the first attempt to selectively leach In using a selected siderophore from end-of-life products with high concentrations of non-targeted elements (i.e. Al, Si, and Ca). This study demonstrates the potential of generating indium-rich leachates, which can be subsequently processed through the GaLIophore technology for In refining.