| Summary: | 碩士 === 國立中央大學 === 化學工程與材料工程研究所 === 90 === The carbothermal reduction and nitridation of rice husk ash with iron powder addition was investigated by weight change measurement. In this study, the operating variables have been discussed include: nitrogen flow rate, amount of iron powder addition in the reactant, pellet-forming pressure, sample weight, and reaction temperature. The analysis of this experiment is conducted by inductively coupled plasma-mass spectrometer (ICP-MS), element analysis (EA), BET surface area, X-ray diffraction (XRD) and scanning electron microscope (SEM).
The experimental results indicated that the conversion of rice husk ash is increased with an increasing nitrogen flow rate and the effect is not appreciable when the flow rate exceeds 500ml/min. The conversion of rice husk ash is increased with an increasing amount of iron powder addition in the reactant. Increasing the pellet-forming pressure could increase the conversion, the effect is not appreciable when the pellet-forming pressure is above 9.65x105 kPa. Moreover, the reaction rate and the conversion of the rice husk ash are significantly increased with higher reaction temperature. The reaction product is fibrous shape β- SiC with iron 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 566.69 kJ /mol when iron powder addition is 1wt% .
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