| dc.description.abstract | The carbothermal reduction and nitridation of silicon dioxide with iron oxide powder addition was investigated by weight change measurement. The aim of this study is to know the effect of different operating variables on the degree of conversion of silicon oxide. In this study, the main operating variables have been discussed included: nitrogen flow rate, amount of iron oxide powder added in the reactant, silica /graphite molar ratio, sample weight, and reaction temperature. The analysis of this experiment is conducted by inductively coupled plasma-mass spectrometer (ICP-MS), BET surface area, X-ray diffraction (XRD) and scanning electron microscope (SEM).
The experimental results indicated that the conversion of silicon dioxide is increased with an increasing nitrogen flow rate, when the gas flow exceeded 500ml/min, the effect is not appreciable. The conversion of silicon dioxide is increased with an increasing amount of iron oxide powder added in the reactant. An excess of graphite is required to promote the degree of conversion of silicon oxide, however, the effect is not appreciable, when the molar ratio is above 5. Moreover, the higher the reaction temperature the faster the reaction rate. The reaction product is fibrous shape β- SiC with iron oxide addition. We conjectured that the formation of liquid Fe-Si alloy is an important way for β- SiC growth. In the chemical reaction controlled region, the activation energy of the reaction is 123.54 kJ /mol when iron oxide powder added is 1wt% and C/SiO2 molar ratio is | en_US |