Carbothermal Reduction Behavior of Micro-silica

Micro-silica, a predominant byproduct of industrial silicon enterprises, presents a substantial opportunity for recycling within the production of industrial silicon. In this study, we used micro-silica from an industrial silicon facility and commercially accessible N991 carbon black as experimental materials. We scrutinized the influence of micro-silica and carbon black on the yield and velocity of SiC formation under varying conditions: temperatures of 1625 °C, 1650 °C, and 1675 °C (1898 K, 1923 K, and 1948 K), disparate CO partial pressures, and diverse SiO₂ to C molar ratios. Our findings reveal that micro-silica initiates melting at a threshold of 1600 °C. At a temperature of 1650 °C, the loss rate of SiO is minimised, resulting in the highest reaction matching degree. Elevated temperatures and increased CO partial pressures correspond to accelerated reaction rates. The carbothermal reaction rate is accelerated by molten SiO₂ and CO. A harmonious correlation was observed between the SiO₂ reactivity of the micro-silica and the SiO reactivity of the carbon black. The reaction between SiO₂ and SiC in the molten state increases the weight loss rate and the reaction rate. The optimal agglomerate composition was determined to be mol_(SiO2): mol_(C) = 1:3.