对磷石膏与纯石膏脱水反应的动力学对比进行了研究。利用同步热分析仪分别测试了磷石膏和纯石膏的脱水过程,采用热重数据计算动力学参数。结果表明:磷石膏和纯石膏脱水都分为两步进行,第一步生成半水石膏,第二步生成无水石膏;两步脱水反应都符合Avrami-Erofeev方程,反应速率受晶核形成和生长速率控制;磷石膏两步脱水活化能分别为97.67,92.6 3 kJ·mol-1,纯石膏对应的活化能是94.56,79.05 kJ·mol-1。

Comparison on kinetics of dehydration reaction of pure gypsum and phosphogypsum was studied. Dehydration process of pure gypsum and phosphogypsum was tested using synchronous thermal analyzer. Kinetics parameters were calculated using thermogravimetric datas. It was found that dehydration reaction of both phosphogypsum and pure gypsum involved 2 stages. Product of the first stage was CaSO4·0.5H2O, and that of the second stage was CaSO4. Avrami-Erofeev equation could be used to describe the 2 stages of the dehydration reaction. The dehydration rate was controlled by the rate of new crystal formation and growth. For the dehydration of phosphogypsum, values of activation energy of the first stage was 97.67 kJ·mol-1, and that of the second was 92.63 kJ·mol-1. For the dehydration of pure gypsum, values of activation energy of the first stage was 94.56 kJ·mol-1, and that of the second was 79.05 kJ·mol-1.