The Oslo type crystallizer (also called classified suspension crystalliser) is well adapted to the production of large, fairly regular sized crystals.
The classifying crystallization chamber is the lower part of the vessel (figures 3 & 4). The upper part is the liquid-vapor separation area where supersaturation is developed by the removal of solvent (water for most applications). The supersaturated liquor flows down through a central pipe and the supersaturation is relieved by contact with the fluidized classifying bed of crystals. Then the mother liquor leaves the crystallizer and passes through the heat exchanger where heat make-up is provided. It is then recycled to the upper part.