水氯镁石的热解机理及动力学

采用热重差热质谱联用技术(TG-DTA-MS)和热分析技术(TG-DTA)研究了水氯镁石热解过程的反应机理和动力学行为. 结果显示，水氯镁石热解分4个阶段，前2个阶段共脱除4个结晶水，后2步脱水和水解并存，第1步的分解反应属于球形对称相界面反应为控制步骤的R3机理，后3步属于Avrami-Erofeev的成核及核成长为控制步骤的A1机理，4步表观活化能Ea分别为81.13, 125.4, 230.4和164.1 kJ/mol，频率因子分别为2.95×1010, 2.70×1015, 4.07×1026和4.75×1016 s-1.

Mechanism and Kinetics of Thermal Decomposition of Bischofite

Reaction mechanism and kinetic behavior of bischofite dehydration were studied by means of the TG-DTA-MS coupling technique and the TG-DTA technique. The results show that there are four steps in the thermal decomposition of bischofite, in the first two steps, four crystallized waters were lost and in the last two steps combined dehydration and hydration took place. The decomposition action of the first step belongs to the R3 mechanism with 3-dimensional phase boundary reaction as the control step, last three steps belongs to the A1 mechanism that Avrami-Erofeev nucleation and nuclei growth as control steps. The apparent active energy of four steps is: 81.13, 125.4, 230.4 and 164.1 kJ/mol respectively, and the frequency factor is 2.95×1010, 2.70×1015, 4.07×1026 and 4.75×1016 s-1 respectively.