A new sustainable concept for silicon recovery from diamond wire saw silicon powder waste: Source control and comprehensive conservation

Metal impurities and SiO2 shell are two key components that must be eliminated for 6 N silicon remanufacturing from diamond wire saw silicon powder waste. Previous research on 6 N silicon recovery has focused more on metal impurity removal without paying sufficient attention to the relationship between metal impurities and the SiO2 shell, even though the surface oxidation of silicon particles is an important factor restricting metal removal. In this study, a novel investigation into the source of metal impurities and the SiO2 shell growth was conducted, combined with acid leaching and linear regression analysis to determine the relationship between the metal impurities and the SiO2 shell. The results indicated that both raw materials displayed strong negative correlations of -0.952 and -0.996 between the removal efficiency and the thickness of the SiO2 shell. And the Al, Fe, Ni, and Mg are more likely to be enriched in the SiO2 shell due to the improper management of metal contaminants and an increase in the O content in the waste stream. Furthermore, source control and comprehensive conservation are recommended for the efficient remanufacture of 6 N silicon. This study provides a new sustainable concept for silicon recovery from diamond wire saw silicon powder waste