METHOD OF PREPARING POTASSIUM CHLORIDE Russian patent published in 2000 - IPC

FIELD: recovery of potassium chloride from sylvinite ores. SUBSTANCE: method comprises dissolving sylvinites, crystallizing the desired product from solution in multistep vacuum crystallizers, classifying solid phase, washing thereof, drying, removing dust, dissolving fine crystalline and dust fractions and recycling the solution to process. Course potassium chloride fractions obtained by hydroclassification of crystallizate suspension are filtered, and fine fractions are directed to controllable vacuum crystallization devices. Fine crystalline potassium chloride resulting from drying and dust removal stages is directed in suspension from into first body of controllable vacuum crystallization device at S:L ratio of 1.0-5.0 and temperature of 70-95. From controllable vacuum crystallization device, condensate is directed to outer compartments of devices. EFFECT: simplified method and higher purity of potassium chloride. 1 ex