Reaction mechanism and kinetics of preparation of aluminium-silicon alloys by carbothermal reduction method
Reaction mechanism and kinetics of preparation of aluminium-silicon alloys by carbothermal reduction method
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发表时间：
2011
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通讯作者：
Di Yue-zhong
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作者：
Di Yue-zhong
利用X射线衍射仪研究了真空石墨炉中不同温度下所得产物的组成，并利用热重-差热分析仪分析了Al 2 O3和SiO2的碳热还原反应过程，在此基础上，探讨了碳热还原法的反应机理，采用差热分析法研究了Al_2O_3和SiO_2碳热还原制备Al-Si合金的动力学。结果表明，Al 2 O3和SiO2的碳热还原过程可分为4个阶段，其中碳化物的形成和分解是关键阶段，在Al 2 O3和SiO2的4种碳热还原机理中，碳化物的生成和分解理论是解释反应过程的最佳理论，用Flynn-Wall-C方法计算了各吸热峰的表观活化能，Ozawa和Kissinger法的反应动力学参数分别为：848.9，945.4，569.7，325.7，431.9和723.1 kJ/mol，并确定了反应动力学方程，同时利用XRF和红外吸收碳硫分析装置对真空石墨炉和电弧炉中得到的产物进行了动力学分析，验证了动力学分析结果的可行性。
The composition of products obtained under different temperatures in vacuum graphite furnace was studied by XRD,and the reaction process of carbothermal reduction of Al2O3 and SiO2 was analysed by TG-DTA as well.Based on these,the reaction mechanism of carbothermal reduction method was discussed.The kinetics of preparation of Al-Si alloys by carbothermal reduction of Al2O3 and SiO2 was studied by means of differential temperature analysis(DTA) at different temperature rising rates of 10,15,20 and 25 K/min.The results show that the carbothermal reduction process can be divided into 4 stages,and the key stage is the formation and decomposition of carbides period.Among the 4 mechanisms of carbothermal reduction of Al2O3 and SiO2,the formation and decomposition of carbides theory may be the best one to interpret the reaction process.The apparent activation energy of each endothermic peak is obtained by Flynn-Wall-Ozawa and Kissinger methods as follows: 848.9,945.4,569.7,325.7,431.9 and 723.1 kJ/mol,and the kinetic equations are also determined.Meanwhile,the feasibility of the results of kinetics analysis is verified using the products obtained in vacuum graphite furnace and arc furnace by XRF and infrared absorption carbon-sulfur analysis unit.