METHOD OF PRODUCING POTASSIUM CHLORIDE Russian patent published in 2012 - IPC C01D3/08 

FIELD: chemistry.

SUBSTANCE: invention relates to a method of producing potassium chloride from sylvinite material. The method involves grinding said material, fractional separation, floatation, hot leaching potassium chloride to form a halite pile and crystallisation of the ready product. Fractional separation of the material is carried out based on the 1 mm class. Floatation is carried out on the +1 mm fraction. Potassium chloride is hot leached in two steps while recycling heat of the halite pile at the third step. A fraction with particle size less than 1 mm is fed for hot leaching. The halite pile formed at the leaching step and heat recycling step undergoes hydraulic classification at each step according to the near-mesh grain 0.2 mm. Caked fractions of the halite pile with particle size +0.2 mm are directed by a countercurrent from the first to the second leaching step, the heat recycling step and extracted via filtration. The hydraulic classification discharge is directed by a countercurrent to the previous step. The discharge from the first step is clarified. Before extraction, the caked fraction of -0.2 mm undergoes countercurrent washing with recycled solution and the clarified solution is cooled with crystallisation of the ready product.

EFFECT: high extraction of potassium chloride from sylvinite material, lower content of fine classes in the end product and high content of KCl therein.

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