Removal of SiC and Si₃N₄inclusions in solar cell Si scraps through slag refining

Abstract

Silicon was recovered from solar cell Si scraps through 42.5 mol% SiO2–42.5 mol% CaO–15 mol% Al2O3 slag refining. The motion behaviors of Si3N4 and SiC were observed in situ and real-time using a high-temperature laser confocal microscope, and the recovery of Si through slag refining was carried out at 1,500°C for 30 min. Results indicated that both SiC and Si3N4 inclusions were concentrated in the slag, and this work provides a clear framework for recycling and reusing solar cell Si scraps.