Preserving silicon (Si) purity through efficient aluminum (Al) and silver (Ag) extraction and recovery from solar cell waste

Journal article, 2025

The large scale deployment of Si PV panels presents significant end-of-life challenges due to their limited lifespan. Effective recycling strategies are crucial to reduce the environmental impact and recovering valuable metals. This study presents a simple yet highly efficient two-stage chemical process to preserve Si purity by sequential extraction of Al and Ag from discarded Si solar cells. In the first stage, Al was dissolved with sodium hydroxide (NaOH) and then precipitated by adjusting the pH with sulfuric acid (H2SO4). In the second stage, the Ag was extracted with nitric acid (HNO3), precipitated with sodium chloride (NaCl), and then reduced to metallic Ag with a glucose. Under optimized conditions, the recovery efficiency for Al and Ag was over 99 %, while the resulting Si substrate reached a purity of >99.9 %. ICP-OES, XRF, XRD, and SEM-EDS confirmed the recovered materials' high selectivity and negligible impurities, highlighting their potential for high-value industrial applications.