PROCESSES INVOLVING THE USE OF ANTISOLVENT CRYSTALLIZATION

摘要

The present invention pertains to a process involving the use of an antisolvent comprising the steps of - feeding water to a salt source to form an aqueous solution comprising said salt if the salt source is not yet in the form of an aqueous salt solution, - feeding said aqueous solution to a crystallizer/settler, - contacting said aqueous solution with one or more antisolvents which force the salt to at least partly crystallize, with one or more crystal growth inhibitors being present in the antisolvents and/or in the aqueous solution, and/or one or more scaling inhibitors being present in the antisolvents and/or in the aqueous solution, - subjecting an overflow of the crystallizer/settler comprising one or more antisolvents and an aqueous salt solution to a separation step wherein one or more antisolvents are separated from the aqueous salt solution by one or more techniques selected from the group consisting of adsorption, ion-exchange, a temperature change induced phase split, a pH change induced phase split, a complexation induced phase split, a pressure induced phase split, evaporation, and extraction, optionally in combination with a nanofiltration step, - removing the crystallized salt from the crystallizer/settler in an aqueous slurry, - optionally, recycling the one or more antisolvents to the crystallizer/settler, and - optionally, recycling mother liquor from the slurry to the first dissolution step and/or to the crystallizer/settler. Preferably, the process is a closed loop process and the salt is sodium chloride. Preferably, the process further comprises a reverse osmosis step before the overflow of the crystallizer/settler is subjected to the separation step.