【作者】 方正东； 汪敦佳； 张传越；

【Author】 Fang Zheng-Dong Wang Dun-Jia Zhang Chuan-Yue(Depaltment of chemistry and environmental engineering, Hubet normal university, Huangshi 435002)

【机构】 湖北师范学院化学与环境工程系；

【摘要】 在298K-1123K温度范围内,用热重一差热综合分析仪研究了地开石在程序升温下的热分解行为。在600K-1000K之间,TG曲线表明其质量损失为13.7%,与理论计算的脱水量相近.根据TG-DTG曲线上的基础数据,联合运用积分法(Coats-Redfern方程、HM方程、MKN方程)和微分法(Achar方程)对地开石脱水反应过程进行了非等温动力学研究,实验结果显示,地开石热分解反应的机理函数为F2,同时求得反应的各动力学参数:反应级数n=2.1,表观活化能E=131.62kJ·nol-1.指前因子A=1.9924×103s-1.作为一种验证方法,使用Ozawa方程对不同升温速率TG曲线上相同分解率处的绝对温度进行线性归分析,求出的E值为133.07kJ·mol-1,此值不仅与上述各种方法的E值相近,也与确定机理函数时的E值相近,可以说明实验求得的动力学参数是可靠的.更多还原

【Abstract】 In this work the thermal decomposition of dickite from Chenxi, Hunan province is investigated by thermogravimetric analysis (TGA). A good agreement is fund with TG curves of dickite and the mass loss is 13.7%(close to the theoretical value). Also, the non-isothermal kinetics of the thermal decomposition of dickite is studied in TG-DTG curves over the temperature range from 298k to 1123k by thermogravimetry and differential thermal analysis in air. Mathematical analysis of TG-DTG data using three TGA kinetic integral methods (Coats-Redfem equation, HM equation, MKN equation) and differential method (Achar equation) shows that the thermal decomposition of dickite accords F2 mechanism. The kinetic parameters such as the activation energy (E=131.62kJ·mor-1), pre-exponential factor (A=1.9924×103 s-1) and reaction order (n=2.1) are reported.Ozawa method is used to analyse the activation energy of the same sample at different heating rate and gives 133.07 kJ·mol-1.The kinetic parameters calculated from different equation are rather close to each other. The kinetic equation of thermal decomposition of dickite is expressed as: d α /dt=1. 9924×103[exp (-131.62×103) /RT] (1-α)2.1更多还原