Abstract
Diamond wire saw silicon powder (DWSSP) is a waste produced during silicon wafer processing for photovoltaic (PV) modules, and it shows significant reutilization potential. However, the presence of moisture leads to silicon oxidation and the formation of a surface SiO2 layer that hinders the recovery of high-purity silicon. In this study, vacuum treatment (VT) was used to prepare low-oxygen silicon by controlling the oxidation and removing moisture from DWSSP waste, thus preventing SiO2 layer formation. The oxygen content in DWSSP decreased by 15.01 %, from 7.26 % to 6.17 %, and the SiO2 layer thickness also decreased by 10.29 %, from 2.04 nm to 1.83 nm after the VT process. Additionally, the VT process lowered the moisture boiling point, facilitating surface evaporation and internal diffusion of moisture. This increased the moisture effective diffusion coefficient from 5.16 × 10−10–6.16 × 10−9 m2 s−1 to 1.21 × 10−9–6.88 × 10−9 m2 s−1 and reduced the apparent activation energy from 32.17 kJ mol−1 to 16.05 kJ mol−1. The efficient moisture removal of VT inhibited the growth of the SiO2 layer to enable the preparation of low-oxygen silicon during silicon recovery.
Published Version
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