钙矾石晶体热分解的动力学

用热分解曲线研究了钙矾石(ettringite,Aft)晶体的热分解动力学.在不涉及分解机理的情况下,用Friedman法求得AFt晶体的分解活化能,并以多元非线性回归对其进行了优化.同时,对4个扫描速率的热分析曲线进行非线性拟合,通过各步动力学参数的变化达到最佳拟合效果,比较各种可能预设过程的拟合结果,从而推断出最概然反应机理函数以及活化能、反应级数和指前因子等动力学因子,并对不同的温度下的AFt晶体热分解行为进行了预测.

THERMAL DECOMPOSITION KINETICS OF ETTRINGITE CRYSTAL

The thermal decomposition process of ettringite (AFt) crystal is illustrated by measured thermal decomposition curves. The activity energy of the thermal decomposition of AFt crystal is analyzed using the Friedman method, without involving any decompo- sition mechanism of solid state, and then optimized by the multivariate non-linear regression. The non-linear fitting is applied to the four decomposition kinetics curves with different scanning speeds. The three kinetics factors of activity energy, reaction order and pre-exponential factor are deduced from the optimal fitting effect by changing the kinetics parameters, and the fitting results of vari- ous possible presupposition processes are compared. The thermal decomposition courses of AFt crystal under different temperatures are forecasted.