Carbothermal reduction of sillimanite in a transferred arc thermal plasma reactor

摘要

Conversion of sillimanite to value-added ceramic materials was investigated by transferred arc plasma processing using nitrogen as the plasma gas. Plasma processing was carried out using sillimanite and sillimanite-carbon mixtures at different power levels. The products were characterized by XRD, SEM and FTIR techniques. Thermodynamic analysis using free energy minimization principle was used to predict the products formed and also analyze the experimental results. The results of these investigations showed that sillimanite can be converted to mullite, or alumina and silicon carbide by careful choice of the operating conditions and sillimanite-carbon ratio.