二水硫酸钙的结晶动力学研究

Study on the Kinetics of Crystallization of Dehydrate Gypsum

用MSMPR结晶器对二水硫酸钙结晶的动力学进行了研究,在假设ΔL定律适应于MSMPR结晶过程的前提下,测量了晶体的粒数密度n和晶体平均粒度L,根据ln(n)-L直线在坐标轴上的截距及其斜率所计算出的晶核粒数密度n0和晶体生长速率G之间的关系推导出结晶过程的成核速率B0。最后从ln(n0)与ln(G)之间的直线关系再推导出二水硫酸钙在60℃情况下的成核速率B0与晶体生长速率G之间的动力学表达式:B0=k2Gi=1.142×103G0.54,同时还研究了添加不同类型的活化疏松剂对二水硫酸钙结晶的影响情况。

MSMPR crystallizer is used to study the kinetics of crystallization of dehydrate gypsum. On the supposition that ΔL law is volid for the MSMPR crystallization process, the relationship between the density of crystal particle number n and the average particle size L is measured. The rate of nucleation B^0 in the crystallization is deduced from the linear relationship between the density of nucleus particle number n^0 and the crystal growth rate G which are calculated from the slope and the intercept of the ln(n)-L straight line. The equation of the rate of nucleation B^0 and the crystal growth rate G at 60℃ for the crystallization process is obtained from the linear relationship between ln(n^0) and ln(G):B^0=(1.142)×10~3G^(0.54). The influence of APA on the crystal habits of dehydrate gypsum has also been studied. Adding a proper amount of APA can make the crystals larger, increase the crystal growth rate of gypsum and reduce the nucleation rate.