METHOD OF PRODUCING MIXTURE OF VERY LOW CONSISTENCY ALPHA AND BETA GYPSUM PLASTER Russian patent published in 2012 - IPC C04B11/02 C01F11/46 

FIELD: chemistry.

SUBSTANCE: invention can be used in the production of construction materials. The method of producing a product containing an alpha hemihydrate of calcium and a beta hemihydrate of calcium sulphate involves feeding 50-75 wt % gypsum slurry into a first reactor, the slurry containing a dihydrate of calcium sulphate and water, and calcination of the slurry in the reactor at conditions sufficient for formation of a partially calcined slurry containing water, dihydrate of calcium sulphate and an alpha hemihydrate of calcium sulphate. The slurry is held in the first reactor at conditions for calcination of gypsum until conversion of 50-95% gypsum into an alpha hemihydrate of calcium sulphate. At least one crystal growth modifier is then added to the dihydrate of calcium sulphate and water before said calcination in the first reactor. Further, the partially calcined slurry is dehydrated to form a water stream and a dehydrated solid phase containing a dihydrate of calcium sulphate and an alpha hemihydrate of calcium sulphate. The hydrated solid phase is fed into a second reactor and calcined to convert at least a portion of the dihydrate of calcium sulphate of the dehydrated solid phase into a beta hemihydrate of calcium sulphate. Calcination of the dehydrated solid phase is carried out in a kettle operating at atmospheric pressure and temperature from 66 to 538°C.

EFFECT: invention reduces consistency of gypsum plaster.

17 cl, 4 dwg, 4 tbl, 3 ex