Patent ID: 6652825
Filing Date: 2003-11-25
Classification: C04B

Abstract:
A method of producing calcium sulfate &agr;-hemihydrate, comprising the steps of:(a) exposing a mixture comprising a calcium sulfate form selected from the group consisting of calcium sulfate dihydrate, calcium sulfate &ominus;-hemihydrate, water-soluble calcium sulfate anhydrite, and mixtures thereof, water, and a crystallization catalyst, to microwave radiation in the range of about 300 MHz to about 300 GHz to produce calcium sulfate &agr;-hemihydrate; and (b) separating at least a portion of said calcium sulfate &agr;-hemihydrate from the product of step (a) to provide a solid comprising calcium sulfate &agr;-hemihydrate and a remainder.