WO 2016/073393 A1

Microwave heating for gypsum manufacturing processes

(22) 03.11.2015

(43) 12.05.2016

(57) Methods of making calcium sulfate whiskers are provided. In one aspect, a method includes autoclaving a slurry of calcium sulfate hemihydrate and water to form calcium ­sulfate hemihydrate ­whiskers in water and microwaving the whiskers to dewater them, wherein the microwaving is effective to prevent a majority of the whiskers from reverting to a dihydrate form. In one aspect, a method includes microwaving calcium sulfate hemihydrate whiskers to form anhydrite calcium sulfate whiskers, wherein the microwaving is effective to remove a substantial amount of chemically bound water from the whiskers.

(71) Georgia-Pacific Gypsum LLC, 133 Peachtree Street NE, Atlanta, Georgia 30303 (US)

(84) ARIPO (BW, GH, GM, KE, LR, LS, MW, MZ, NA, RW, SD, SL, ST, SZ, TZ, UG, ZM, ZW), Eurasian (AM, AZ, BY, KG, KZ, RU, TJ, TM), European (AL, AT, BE, BG, CH, CY, CZ, DE, DK, EE, ES, FI, FR, GB, GR, HR, HU, IE, IS, IT, LT, LU, LV, MC, MK, MT, NL, NO, PL, PT, RO, RS, SE, SI, SK, SM, TR), OAPI (BF, BJ, CF, CG, CI, CM, GA, GN, GQ, GW, KM, ML, MR, NE, SN, TD, TG)

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