The carbothermal reduction and nitridation kinetics of silicon dioxide/carbon pellet were studied under conditions of various reaction parameters including gas now rate, pellet size, pellet-forming pressure, C/SiO2 molar ratio, grain sizes of both carbon and silicon dioxide, and reaction temperature by using a thermal gravimetric analysis (TGA) technique. The rate equation and kinetic model expressions of the nitridation process in the chemical reaction-controlled region were presented. The activation energy investigated in the temperature range between 1623 and 1748 K was 448 +/- 10 kJ/mol. The reaction-mechanism including the formation of a gaseous SiO intermediate was also discussed. The SiO formed from SiO2 being a rate-determining step was confirmed by experimental results. These theoretical developments correlated sufficiently with observed experimental results.
