Sustainable System for Raw-Metal Recovery from Crystalline Silicon Solar Panels: From Noble-Metal Extraction to Lead Removal

Methods for recovering raw materials from end-of-life solar panels were studied. A process for removing the hazardous element lead (Pb) in solar panels was also investigated. We achieved recovery rates of 80%, 79%, and 90% for Si, Cu, and Ag. We also achieved a removal rate of 93% for Pb. We immersed the cells in 5 M nitric acid solution under agitation at 200 rpm to dissolve the metals. We sequentially recovered Si, Cu, Ag, Al, and Pb. To recover Si, a process for removing the Al electrode and SiNx layer was required. LIX84-I and 150 g/L H2SO4 solution were used to respectively extract and strip Cu. The purity of Ag powder after reduction Ag2O was 99.7%. An electrolytic refining process increased the Ag purity to 99.99%. We were able to achieve a removal rate of 93% for Pb through neutralization and sulfurization.