If the solubility of the salt changes only a little at fluctuating temperatures the evaporation crystallization preferably finds application. In this process a solution is crystallized by evaporating the solvent through the supply of heat.
The special design of the evaporation chamber makes is possible to operate the evaporation crystallizer as classifying crystallizer. In this case the crystals are separated by classification according to size in a sedimentation zone. The coarse portion may be discharged through an extra outlet while the fine portion remains in suspension.