Efficient Recovery of Silver and Aluminum from End-of-Life Photovoltaics: A Two-Step Leaching Approach

Abstract

Recycling solar panels is crucial to mitigating the environmental impact of the growing volume of end-of-life photovoltaic waste and to conserve valuable resources, while achieving high purity in recovered materials ensures their effective reuse in the manufacturing of new solar panels, contributing to a sustainable and circular economy. This study proposes a two-step leaching process to recover Ag and Al from the silicon fraction of EoL photovoltaics (PVs). In the first-stage laboratory scale tests, 99% Al was extracted using 5% HCl at room temperature (19 °C) for 3 h The Al was precipitated as oxide from the solution. The silicon residue was then leached with 0.5 M HNO3 at 85 °C for 2 h, extracting 99% Ag and producing Si with 99.83% purity. The silver was precipitated to produce metallic Ag with >99.9% purity. Then, 95.63% of Pb in the nitric acid effluent was removed using ion exchange resins. Further, methods to mitigate the effluent solutions were recommended and the entire process was presented in a flowsheet.