Comparison on the solid-state desilication kinetics of silicon manganese powder by microwave heating and conventional heating
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摘要: 采用微波加熱和常規加熱對硅錳粉和巴西粉錳的脫硅反應進行了動力學行為研究，以巴西粉錳為脫硅劑，與硅錳粉中的硅發生氧化還原反應.微波加熱和常規加熱分別加熱到不同溫度并保溫一定時間，測定產物中硅含量并計算固相脫硅反應的表觀活化能.實驗表明：單一和混合料均可在微波場中快速升溫.隨著溫度的升高和保溫時間的延長，兩種加熱方式脫硅率均隨之提高，在相同實驗條件下，微波加熱的脫硅率和反應速率均高于常規加熱，微波加熱可以提高固相脫硅率；微波加熱固相脫硅反應的限制性環節為擴散環節，其表觀活化能為102.93 kJ·mol-1，常規加熱脫硅反應的表觀活化能為180 kJ·mol-1，說明微波加熱能改善固相脫硅的動力學條件，提高固相脫硅反應速率，降低脫硅反應的活化能.Abstract: The solid-state desilication kinetics of silicon manganese powder and Brazil manganese powder was investigated by microwave heating and conventional heating. During the two processes, Brazil manganese powder which reacted with silicon in silicon manganese was used as the desilication agent. The mixture was heated up to different temperatures and preserved heat for some time by microwave heating and conventional heating, respectively. The silicon content of desilication materials was measured and the apparent activation energy of desilication reaction was calculated. The results show that the single raw material and the mixture could be heated up in the microwave field in a short time. The desilication rate increases with the increase of heating temperature and holding time by both heating methods. The desilication rate and the reaction rate under the microwave field are significantly higher than those by conventional heating. Microwave heating can increase the rate of solid phase desilication. The restrictive step of solid-state desilication kinetics of silicon manganese powder and Brazil manganese powders by microwave heating is the diffusion step. The apparent activation energy of desilication reaction under the microwave field is 102.93 kJ·mol-1, but the apparent activation energy of desilication reaction by conventional heating is 180 kJ·mol-1. The microwave heating field can improve the kinetics condition of solid phase desilication, increase the reaction rate of solid phase desilication and reduce the activation energy of desilication reaction.
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參考文獻
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