摘要
利用热失重技术,以碳酸钙为模型物质,进行了样品质量为2.52～18.37mg、升温速率为2～20℃/min的不同条件下的非等温热分解研究。对改进的积分法和Coats-Redfern方法的计算结果进行了对比。确定了碳酸钙热分解速率受相界反应控制的机制,热分解的活化能为250～370kJ/mol,频率因子为2.65×10^(10)～3.49×10^(19)。研究了升温速率和样品质量对碳酸钙热分解的影响以及热分解过程的补偿效应规律。
Non-Isothermal gravimetric experiments in different conditions were made, by applying high temperature differential thermal balance methods and using calcium carbonate as a model substance. The kinetic parameters calculated by improved integration method and Goats-Redfern method were compared. It was also determined that activation energy and frequency factor of the decomposition of calcium carbonate were 250～370kJ/mol and 2.65×10^(10)～3.49×10^(19), respectively. The decomposition rate is controlled by the mechanism of rate-controlling process on phase boundary reaction. The effect of heating reat and sample mass and the kinect compensation effect in the decomposition of calcium carbonate were discussed.
关键词
固体
热分解
动力学
碳酸钙
热分析
thermal decomposition method
kinetics
thermal analysis
calcium carbonate
compensation effect
