Electrorefining in Aqueous Chloride Media for Recovering Tin from Waste Materials

The growing amount of lead-free tin-containing waste material generated by the electronic industry necessitates effective recycling methods. This study investigates the electrorefining process utilizing hydrochloric acid tin chloride electrolyte solutions, which offer a flexible and economical approach to recovering impure tin from waste. To mitigate the drawbacks of traditional alkali stannate and sulfuric acid baths, the performance of the hydrochloric acid solution is optimized by adjusting solution composition and current parameters. Results indicate that the strong chloro-complex formation in the electrolyte enhances the stability of Sn(II) species and supports cathodic deposition of high-quality tin. Moreover, the implementation of periodically reversed current significantly improves virtual current efficiency and the morphology of electro-crystallization, while minimizing cathode corrosion. Despite the tendency for dendritic crystal growth, which presents challenges in cell arrangement and cathode handling, the cathodic deposit can be easily removed and melted to yield high-purity tin (~99.99%). This method, therefore, represents a promising strategy for sustainable metal recovery in the electronic sector.