Patent ID: 7338561

Claim:
Preparation method of crystallized sugar from an aqueous solution containing one or several sugars, multivalent cations, monovalent metal cations, monovalent anions and multivalent inorganic anions and/or organic acid anions, characterized in that it comprises operations: (a) of replacement of at least a part of said multivalent cations and/or of said multivalent inorganic anions and organic acid anions by monovalent metal cations and monovalent anions, respectively, in order to obtain an aqueous solution depleted in multivalent cations and/or multivalent inorganic anions and organic acid anions, and containing the said monovalent metal cations and monovalent anions, (b) of nanofiltration of the solution resulting from operation (a) in order to obtain as a retentate, a sugar aqueous juice enriched in sugars, in multivalent cations and in multivalent inorganic anions and/or in organic acid anions, and as a permeate, an aqueous effluent enriched in monovalent anions and monovalent metal cations, and (c) of crystallization of at least a part of the retentate resulting from operation (b), in order to obtain crystallized sugar and a mother liquor enriched in monovalent anions and monovalent metal cations.