叶蛇纹石同步辐射X射线粉末衍射脱水动力学研究

采用同步辐射X射线粉末衍射方法在等温条件下研究粒径为~5 μm的叶蛇纹石脱水动力学，在680、700、710和720℃下观测叶蛇纹石脱水前后特征峰随时间变化的特征。结果发现，随加热时间的增加，叶蛇纹石的特征峰缓慢消失，伴有镁橄榄石特征峰出现，但无顽火辉石相出现。通过Avrami方程，获得叶蛇纹石脱水反应级数（n）为1.1~1.3，表明叶蛇纹石脱水过程受晶界成核控制。利用Arrhenius方程，获得叶蛇纹石脱水仅出现镁橄榄石相所需活化能为105.97 kJ/mol，指前因子为333.62 s^-1。

Kinetic study of antigorite dehydration using synchrotron X-ray powder diffraction

Synchrotron X-ray powder diffraction method was used to study dehydration kinetics of antigorite with particle size of ~5 μm. The isothermal heating method was used to observe antigorite dehydration at 680, 700, 710, and 720 ℃, respectively. It was found that, with the increase of heating time, the characteristic peak of antigorite slowly disappeared and the characteristic peak of forsterite formed, but no enstatite appeared. The reaction order n is 1.1~1.3 by the Avrami equation, indicating that antigorite dehydration is controlled by grain boundary nucleation. Activation energy for the formation of forsterite from antigorite is 105.97 kJ/mol, and the pre-exponential factor is 333.62 s^-1 in the Arrhenius equation.