碳热还原法制取铝硅合金的反应机理及其动力学  

Reaction mechanism and kinetics of preparation of aluminium-silicon alloys by carbothermal reduction method

作　　者：杨栋[1] 冯乃祥[1] 王耀武[1] 彭建平[1] 王紫千[1] 狄跃忠[1] 

机构地区：[1]东北大学材料与冶金学院,沈阳110004

出　　处：《中国有色金属学报》2011年第1期227-235,共9页The Chinese Journal of Nonferrous Metals

基　　金：国家高技术研究发展计划资助项目(2007AA06Z116)

摘　　要：利用XRD、TG/DTA技术分别分析真空碳管炉内不同反应温度下的物相组成和碳热共还原Al2O3、SiO2的反应过程,并在此基础上探讨碳热还原法制取铝硅合金的反应机理。分别采用10、15、20和25 K/min升温速率的差热分析,研究动态氩气气氛中碳热法制取铝硅合金的反应动力学。结果表明:碳热还原反应过程可分为4个阶段,其中,以碳化物的生成与分解阶段为主。碳热还原反应的4种还原机理中,碳化物的生成与分解理论能较好地解释反应过程中出现的反应现象。各个吸热峰的表观活化能分别为848.9、945.4、569.7、325.7、431.9和723.1 kJ/mol,给出了各个吸热峰的动力学方程。同时,利用XRF和红外定硫定碳仪对碳管炉和电炉所得产物组成的定量分析,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.

关 键 词：碳热还原 差热分析 铝硅合金 反应机理 动力学方程 

分 类 号：O643.1[理学—物理化学]