黑钛液中七水硫酸亚铁结晶动力学性质

Crystallization kinetics of FeSO_4·7H_2O in black titanium solution

采用平衡法研究了七水硫酸亚铁在黑钛液中的溶解度,通过拟合得到了其溶解度方程,并利用FBRM在线监测溶液结晶情况,测量了其结晶介稳区。通过间歇动态法研究了七水硫酸亚铁的结晶动力学,采用矩量变化法求解了粒数衡算方程,并利用最小二乘法对动力学实验数据进行多元线性回归后得到七水硫酸亚铁成核速率和生长速率方程,结果表明:搅拌速率和降温速率对七水硫酸亚铁结晶过程影响显著,因此,针对搅拌速率和降温速率对结晶工艺的影响进行了分析,并对优化前后七水硫酸亚铁产品进行了对比,发现优化后晶体呈规则的棱形,产品粒度明显增大,小颗粒晶体显著减小。

The solubility of FeSO4＆#183;7H2O in black titanium solution is studied using balance method and the crystallization metastable zone is measured with FBRM online monitoring. The crystallization kinetics of FeSO4＆#183;7H2O is investigated with the method of moments through batch cooling crystallization experiments based on the population balance equation. Nucleation rate equation and growth rate equation are obtained by regressing the experimental data with the multiple linear least square method. The key parameters of the crystal size distribution are associated with stirring rate and solution temperature, which can be used to predict and control the crystal size distribution in industrial crystallization process. According to the crystallization kinetics of FeSO4·7H2O, cooling rate and stirring rate have a great effect on crystal size. Cooling crystallization process is carried out under the optimized operating conditions. The results show that the particle size of FeSO4·7H2O increases significantly and small particles reduces greatly, compared to the original process.