This Demonstration shows a model for the evaporative crystallization process. A mixture of a fresh feed and recycle stream, both containing potassium chloride (KCl) in water, enter an evaporator. A fraction of the water that enters the evaporator exits as vapor, and the remaining KCl solution enters a crystallizer and filter. A filter cake and a portion of saturated KCl solution are removed from the crystallizer and filter, and the rest of the aqueous KCl solution is recycled by mixing it with the fresh feed. The fraction of crystals out of solution in the stream exiting the crystallizer and filter can be varied. The temperature of the evaporator as well as the temperature of the crystallizer and filter can be varied. The solubility of KCl increases linearly with temperature.