METHOD OF PRODUCING ALPHA-HEMIHYDRATE OF CALCIUM SULPHATE FROM DEHYDRATE OF CALCIUM SULPHATE Russian patent published in 2011 - IPC C04B11/28 

FIELD: chemistry.

SUBSTANCE: invention relates to methods of producing alpha-hemihydrate of calcium sulphate. The method involves loading dehydrate of calcium sulphate into an autoclave with a mixer, indirect heating of the autoclave, controlled addition and admixing water, prevention of adherence of material to the surface of the reaction space via movable chains fitted on blades and/or driven shaft of the autoclave with a mixer, periodic or continuous control of pressure in the reaction space by releasing vapour when pressure inside reaches a certain level, where vapour is moves through a cyclone separator and a servovalve, feeding cold air for post-drying and removing spent material. The method is realised using apparatus which has an autoclave with a mixer, having double walls and heated indirectly, spray nozzles distributed on the jacket of the autoclave, freely hanging chains attached in the region of the mixer, a cyclone separator, as well as a Venturi scrubber fitted outside the autoclave with a mixer.

EFFECT: high reliability of the apparatus, low power consumption.

13 cl, 2 dwg