United States Gypsum Company

Richard F Stone

Larbi Bounini

Donald R Janninck

Otto L Dozsa

Hydrodynamic pumping of the fluidized calcining mass in a kettle is set up by the continuous flow of the mass to and from heating rods immersed therein which are constantly emitting at least about 1 British Thermal Unit of heat per minute per square inch of the surface of the rods. The transfer of heat from the walls and bottom of the kettle is enhanced so that more of the available heat is actually absorbed than in a kettle lacking such heating rods. The rate of calcination may be increased while the rate of heat input is decreased.

Highly efficient calcination of gypsum to hemihydrate

A process and apparatus for producing a healed stucco having lowered water demand without loss of normal strength development potential which comprises, while blending a small amount of water with the calcined gypsum, simultaneously or substantially simultaneously grinding the calcined gypsum so as to increase the surface area of the calcined gypsum particles while incorporating about 1-10% by weight of the calcined gypsum of free water.

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Buffalo Grove, IL, United States of America

Richard F Stone