Patent ID: 6692720
Filing Date: 2004-02-17
Classification: B01D,C01D,C01F

Abstract:
Process for the production of sodium chloride crystals from a sodium chloride brine contaminated by potassium chloride and sulphate ions, according to which,in a first stage, a calcium compound is added to the brine to precipitate calcium sulphate, which isolated, and an aqueous solution is collected, in a second stage, the aqueous solution from the first stage is subjected to evaporation, to crystallize sodium chloride, and sodium chloride crystals and an aqueous mother liquor are collected separately, and, in a third stage, the aqueous mother liquor from the second stage is subjected to cooling in order to crystallize at least a portion of the potassium chloride, wherein the amount of calcium compound in the first stage and the cooling in the third stage are adjusted so that the sulphate ions precipitate in the form of glauberite in the first stage and of glaserite in the third stage.