The solubility of FeSO4·7H2O in black titanium solution is studied using balance method and the crystallization metastable zone is measured with FBRM online monitoring. The crystallization kinetics of FeSO4·7H2O 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.