The precipitation crystallization kinetics model for fluorite was deduced based on the two-step crystallization theory of mass diffusion and surface reaction. Using calcium chloride as precipitating agent

the crystallization kinetic data for fluorite were measured in steam ammonia wastewater using batch crystallization and on-line particle monitoring technologies. The crystallization kinetics model parameters were optimized with nonlinear optimization techniques and verified by experimental data. The results showed that the model and model parameters were nice with the average relative error of about 3.37% between the model values and the experimental data. The fluorite precipitation crystallization process was controlled by surface reaction and coalescence phenomenon between fluorite particles happened. Simulation results with the kinetics model indicated that when the initial calcium ion concentration was constant

the higher the initial concentration of fluoride ions

the faster the fluoride ion concentration decline in the initial stage. The initial fluoride ion concentration was too high or too low

eventually they were unfavorable for lower fluoride ion concentration. Appropriate increase in operating temperature may promote fluorine ion purification

however

too high temperature was negative.