High-Efficiency Silver Recovery from End-of-Life Photovoltaic Modules via Hydrodynamically Optimized Electrowinning

Abstract

The proliferation of photovoltaic (PV) installations necessitates sustainable methods for managing end-of-life modules. This study addresses the environmental drawbacks of traditional hydrometallurgical recycling, such as the use of hazardous chemicals and high CO2 emissions, by developing a novel electrowinning process for silver (Ag) recovery. We introduce an optimized system that synergistically combines a hemispherical stainless-steel cathode, which also serves as the reaction vessel, with magnetically induced forced convection to overcome mass transport limitations. This streamlined technique directly extracts Ag from a nitric acid-based leachate, achieving recovery rates exceeding 99% and a purity of approximately 99.4%. Computational fluid dynamics (CFD) simulations were employed to validate the mechanism, demonstrating that magnetic stirring enhances ion flux to the cathode surface, thereby increasing deposition efficiency. A systematic investigation of process parameters revealed that cathode geometry and stirring speed are critical factors influencing the recovery rate. Compared to conventional chemical deposition methods, the developed process reduces CO2 emissions by approximately 15%, cuts operational costs by over 65%, and reduces the total processing time by nearly 60%. These findings present a practical, efficient, and more environmentally benign pathway for high-purity metal recovery, contributing significantly to the circular economy for PV materials.