THE INFLUENCE OF THE MAGNESIUM ADDITIVE CONCENTRATION ON THE SYNTHESIS OF SILICON CARBIDE FROM RICE HUSKS

Silicon carbide is a compound known for its excellent wear resistance, thermal conductivity, and high-temperature stability. A key focus in the current SiC synthesis research is concerned with using biomass as a precursor. Rice husks represent a typical biomass material employed in producing SiC, though the conversion efficiency is often suboptimal. This study investigates the influence of magnesium additives on enhancing the SiC formation from rice husks. A mixture of rice husks, silica gel, and magnesium in various ratios was sintered at 1000 degrees C in a CO2 atmosphere to synthesise SiC. The chemical composition, mineral phases, and microstructure analysis indicated that a rice husk-to-magnesium ratio of 1:6 was optimal for improving SiC yield. However, the additives also introduced unwanted impurities, which could be effectively removed through washing with hydrofluoric (HF) acid. After this purification step, the SiC content reached 84.25 % by weight. The final product exhibited both alpha-SiC and beta-SiC allotropic forms, contributing to its enhanced mechanical strength and thermal stability.