METHOD OF PRODUCING SCHOENITE Russian patent published in 2009 - IPC C01D5/12 C01F5/40 

FIELD: chemistry.

SUBSTANCE: crushed polyhaite is calcined at temperature over 450°C and dissolved, thereby obtaining a suspension from which a mixture containing halite, calcium sulphate and insoluble compounds is separated by thickening and filtration. The obtained clear solution is cooled at temperature ranging from 15 to 25°C for crystallisation of schoenite. The crystallised schoenite is dried at temperature ranging from 190 to 210°C, and the alkaline solution obtained after crystallisation is returned for dissolving.

EFFECT: prevention of lumping of polyhalite during calcination, reduced energy consumption and destruction of liquid wastes.

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