磷石膏与纯石膏脱水反应的TG、DSC表征与分析

Characterization and analysis of TG and DSC on the thermal dehydration of phosphogypsum and pure gypsum

测试了磷石膏和纯石膏的脱水的TG、DTG、DSC对比分析二者的脱水特性。结果表明,磷石膏和纯石膏脱水的相似点是脱水都分为两步进行,为吸热反应,产物分别是Ca SO4·0.5H2O和Ca SO4;纯石膏脱水的起始反应温度和DTG峰值温度都低于磷石膏,失重率都高于磷石膏,说明磷石膏脱水要比纯石膏脱水相对困难一些;纯石膏较磷石膏脱水反应历程短,峰较尖锐,峰值温度略低;特征温度点随升温速率的增加而升高。

The dehydration process of phosphor gypsum and pure gypsum is analysis and research by a Netzsch STA 409 PC simultaneous TG/DSC instrument. Characteristics of the dehydration process of phos- phor gypsum and pure gypsum was analyzed through the method of comparison. Results show that the dehydration process of phosphor gypsum and pure gypsum product are CaSO4 · 0.5H2O and CaSO4 the weight loss phosphorus gypsum, initial reaction temperature and DTG that of the phosphorus gypsum the dehydration capacity are very similar with two absorption stage, the rate of pure gypsum is greater than that of the peak temperature of pure gypsum are lower than of phosphor gypsum is more difficult than pure gypsum dehydration ability;the dehydration reaction process of pure gypsum is shorter than that of phos- phor gypsum, the peak is sharper and the peak temperature is slightly lower, the peak temperature in the DSC curve increases with heating rate.