Influence of the Grinding Media Applying in the Soft Coal and Waste Biomass on the Carbothermic Reduction Process of Silica

In this study, experiments were conducted to evaluate the effects of the composition of a grinding medium on the reactivity of mixed carbon materials. Orange peel (OP) was mechanically ground into powder with soft coal (SC) under different media. The potential value of the carbonaceous reducing agent in industrial silicon production was assessed based on reaction performance during thermal gravimetric analysis. The samples underwent Fourier transform infrared spectroscopy, Raman spectroscopy, and scanning electron microscopy to investigate the structural transformation and morphology of the reactants. The results indicated that the initial temperature of the reaction could be decreased by wet grinding. The maximum reaction rate of WGE–Si (SC, OP and silica mixed by wet grinding with ethanol) increased by 15.87% with a 7.19% reduction in activation energy relative to that of WGE. An unconventional method of grinding was proposed in this study, and our experimental results demonstrated its validity and superiority. Analysis and calculation results provide theoretical guidance and reference for the practical application of SC and waste biomass as a valuable and renewable carbonaceous reducing agent in the sustainable and clean production of silicon.