Process for continuous production of large crystal products

Abstract

The invention relates to a continuous process for preparing large crystal products of a crystalline product in a fluid bed crystallizer, said fluid bed crystallizer comprising a crystallization vessel and means for mechanically impacting of crystals; and connected to the crystallization vessel (i) a feed line; (ii) an external circulation circuit comprising means for determining properties of the slurry in the external circulation circuit and a heat exchanger; and (iii) a product withdrawal line, wherein—for any specific crystalline product and at any flow rate chosen in the external circulation circuit—the weight percentage of crystals of the crystalline product in the slurry in the external circulation circuit, ECCWPC, is controlled by said means for determining properties of the slurry within a specified and predetermined narrow range having a maximum and minimum value not more apart than at most 25% by weight and falling within the range of from 1 to 50% by weight. Preferably, the crystalline product is ammonium sulphate, and the ECCWPC is controlled within a range of from 3 to 20% by weight, preferably of from 5 to 15% by weight, more preferably of from 8 to 12% by weight. The product obtained may be further subjected to size classification by screening.

Dependencies are inferred from the claim text.