空气气氛中滑石的热分解动力学实验研究

Experimental study on thermal decomposition kinetics of talc under the condition of air atmosphere

含水矿物的热分解动力学研究对于了解俯冲带中-深源地震的成因机制具有重要意义.本文用综合热分析仪（TG-DSC）研究滑石在动态空气气氛下的热分解过程,利用热重（TG）数据对滑石的热分解动力学进行分析.利用Friedman法和FWO法,分别计算滑石热分解过程中的表观活化能Ea和指前因子A,并以Friedman法求得的活化能为初始值,通过非线性回归拟合得到热分解过程最可能的反应机理和动力学参数.研究结果表明,滑石在830-1 050℃内发生热分解,此过程为n级反应,表观活化能Ea为344.2 k J/mol,指前因子A为4.9E12 s-1.

Study on thermal decomposition kinetics of hydrous minerals is important to the exploration of the formation mechanisms of intermediate-deep earthquakes occurred in subduction zone. In the present work thermal decomposition of talc was studied by using thermogravimetric （TG） techniques under the condition of dynamical air atmosphere. The model-free methods including Friedman and FWO were employed to determine the activation energy （Ea） and the pre- exponential factor （A）. Based on the initial values derived from Friedman method, the most probable kinetic model of the dehydration reaction was obtained by using the multivariate non-linear regression approach. The results showed that talc decomposed in the temperature range of 830 1 050℃ and the most probable kinetic model could be expressed as f（a） = （1 - a）n and G（a） = （1 - （1 - a） 1-a） ）/（1 - n）, with the derived values of 1.7,344.2 kJ/mol, and 4.9E12 s-1 for n, Ea, and A, respectively.