Effect and mechanism of thiourea on indium electrocrystallization in sulfate electrolyte

Abstract

In the realm of advanced technologies, indium is a critical metal with wide-ranging applications, and the efficient purification of indium has emerged as a topic of significant industrial interest. This study investigates the use of gelatin and thiourea as additives to mitigate the adverse effects of dendrite growth during indium electrolysis. Additionally, agitation was incorporated into the electrolysis process to further enhance the morphology of cathodic indium deposition. Under optimal conditions of 0.5 g/L gelatin and 0.05 g/L thiourea, current efficiency increased by 6.2 %, while the recovery improved by 5.7 %. Scanning electron microscopy (SEM) was employed to examine the dendritic growth of indium on titanium electrodes. The findings indicated that the combination of gelatin, thiourea, and stirring led to a more compact and uniform coating. The electrodeposition mechanisms of indium in various electrolytic environments were further elucidated through cyclic voltammetry and chronoamperometry, revealing that under the influence of gelatin and thiourea, the nucleation process on titanium shifted to a continuous mode.