Sequential hydrometallurgical – electrochemical process for high-purity Ag and Cu recovery from PV waste: Selective Ag electrowinning and sulfate-optimized Cu deposition

The transition to multi-busbar (MBB) photovoltaic modules utilizing silver-coated copper wires complicates the selective recovery of high-purity metals from end-of-life (EoL) waste. To address this, we developed an integrated hydrometallurgical – electrochemical process for the selective, chemical-saving recovery of Ag and Cu. The method involves nitric acid leaching followed by selective Ag electrowinning using an inert stainless-steel anode, achieving > 99% recovery without Cu contamination. Subsequently, the electrolyte is converted to a sulfate system for Cu electrowinning using a dimensionally stable anode. Optimization at 2 V yielded > 86% Cu recovery with a specific energy consumption of 4.42 kWh/kg. Comparative technoeconomic and life-cycle assessments demonstrate that this sequential strategy improves the operational profit margin by approximately 4.7% (USD 707.37/ton) and reduces global warming potential by 26.4% (397.4 kg CO₂ eq/ton) compared to conventional methods. The elimination of hazardous reductants like hydrazine and optimized energy demand highlight the process's sustainability. This work presents a chemically streamlined and economically viable solution for PV waste recycling, with acid recovery identified as a key area for future process optimization.