An efficient way of recycling silicon kerf waste for synthesis of high-quality SiC

In this paper, an efficient approach of recycling and reutilizing of silicon kerf waste (SKW) to prepare high-quality silicon carbide (SiC) by carbothermic reduction method is reported. SKW used as silicon source and petroleum coke as carbon source were submitted to the induction furnace for high-temperature smelting. The effects and mechanism of smelting temperatures and time on micro morphology, crystal structure, and purity of the obtained high-quality SiC were studied by X-ray diffractometry, scanning electron microscopy (SEM), Fourier transform infrared (FTIR) as well as the Raman and photoluminescence (PL) analyses. Raman and PL analyses have verified the existence of SiC crystal types as 6H and 3C. The SEM and energy dispersive X-ray spectroscopy results show that the SiC particles size increases with the increasing smelting time and demonstrate that the iron impurity was enriched at the edges of SiC which can be easily removed by the subsequent acid leaching. The enrichment process can be accelerated by the increase of temperature. In addition, the carbothermic reduction mechanism of SKW was studied in detail. The obtained SiC powder after purification can reach 98.7% through this new method, which is of low cost, high efficiency, and environment friendly.