Review of Silicon Recovery from Diamond Wire Saw Silicon Powder Waste Based on Hydrometallurgical Process

The photovoltaic (PV) industry is developing rapidly to support energy transformation and emission reduction. In the whole PV industry chain, diamond wire saw silicon powder (DWSSP) waste is the most promising secondary resource for recycling high-purity silicon. DWSSP mainly contains metal impurities, and the treatment process based on hydrometallurgy can effectively remove metal impurities. The current DWSSP recovery process was divided into three categories: direct acid leaching, pyrometallurgy followed by acid leaching, and acid leaching followed by pyrometallurgy. This paper gives a comprehensive overview of these three purification processes from the aspects of impurity removal and recovery yield. The results suggest that acid leaching followed by pyrometallurgy is currently the most effective process for removing metal impurities from DWSSP. Moreover, this study underscores the potential for enhancing the purity of reclaimed silicon through the application of external field reinforcement, oxygen-regulated acid leaching, and surfactant-facilitated organic acid leaching and points out the development direction for promoting silicon recovery from DWSSP.