Fabrication of silicon carbide particles from recycled polysilicon photovoltaic cells

In this study, a recycling method for the recovery of polysilicon (poly-Si) wafers from end-of-life poly-Si photovoltaic (PV) cells and the synthesis of high-purity silicon carbide (SiC) using the recovered poly-Si wafers are reported. First, an end-of-life poly-Si PV module was etched by acid treatment, using a mixture of hydrofluoric acid (HF) and nitric acid (HNO3), to recover the poly-Si wafer. The purified wafer was milled using high-energy milling to form Si powders to prepare a fine SiC powder. Then, the SiC powder was synthesised using spark plasma sintering with a mixture of poly-Si powder and carbon black. By analysing the morphology and crystal structure of the SiC powders synthesised at different reaction temperatures, the optimum temperature for synthesising the fine SiC powder was determined. After milling, the poly-Si and SiC powders were washed using a HF solution to remove the oxide impurities from the powders. Thus, a fine SiC powder with an oxygen content of 0.11% was obtained.