Process for the crystallization of non-sucrose substances
AssigneeFinnfeeds Finland Oy
InventorsKristian Eriksson, Juha Nurmi, Jouko Virtanen
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Abstract
The invention relates to a process for the crystallization of substances having a narrow metastable supersaturation zone. In the process the saturation of a solution is gradually increased and the solution is seeded for the crystallization. The seeding is performed at a seeding point which is selected in response to a signal received from said process indicating imminent or initial spontaneous nucleation. The process provides a good crystal yield and a crystalline product having a uniform crystal structure and a narrow crystal size distribution.
Claims19
A process for the crystallization of a substance having a narrow metastable supersaturation zone, wherein the saturation of a solution of said substance is gradually increased and said solution is seeded for the crystallization, characterized in that seeding is performed at a seeding point which is selected in response to a signal received from said process indicating imminent or initial spontaneous nucleation, said seeding initiating a controlled crystallization based on crystal growth around the nuclei provided by said seeding and enabling the production of a crystalline product having a uniform crystal structure and a narrow crystal size distribution.
A process according to any one of the preceding claims, wherein said substance is betaine, a salt or derivative thereof, an inorganic salt, or the like crystallizable compound having a narrow metastable supersaturation zone.
A process according to any one of the preceding claims, wherein said signal is detected in a portion of said solution which is subjected to different physical conditions than the main part of said solution.
A process according to any one of the preceding claims wherein said crystallization comprises an evaporative crystallization or a cooling crystallization.
A process according to any one of the preceding claims, wherein said seeding point is selected so as to provide seeding immediately after the first spontaneous crystallization has been detected.
Dependencies are inferred from the claim text.