Modeling the Nucleation and Growth of Calcium Carbonate Crystals in Cooling Crystallizer Unit

This paper covers the nucleation and growth of calcium carbonate crystals in a cooling crystallizer unit. In nucleation process, small particles are generated in a new phase inside the homogenous supersaturated phase, this situation occurs by cooling or warming. The system was modeled to assess the effect of temperature and mixer rotation on the size of produced crystals. Experiments were performed at 9 different temperatures and 5 different mixer rotations and the effect of these two parameters on the size of carbonate calcium crystals were studied. The results demonstrated that temperature decrease would lead to increase of the crystals diameter. Moreover, the increase in mixer rotation causes decrease in the crystals diameter. Based on these findings, the procedure of cooling the crystallizer was modeled in the meta-stable Region. Furthermore, optimum rotation of the mixer and the optimum measure of the seeds were calculated for the discrete cooling crystallizer. Finally, the model that defines the relation between the mixer rotation and the crystals' diameter, the number of crystals and diameter of particles, as well as the number of particles and mixer rotation was determined to be developed.