PRODUCTION OF ALPHA-TYPE GYPSUM HEMIHYDRATE

PURPOSE:To continuously and stably produce an alpha-type gypsum hemihydrate having high purity, by converting a slurry of gypsum dihydrate to alpha-type gypsum hemihydrate by hydrothermal treatment under pressure, cooling the resultant slurry of alpha-type gypsum hemihydrate in pressurized state, se...

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Bibliographische Detailangaben
Hauptverfasser:	INOUE KENJI, ONIZUKA MASAKAZU, SHINODA NAOHARU, IWASHITA KOICHIRO, TATANI ATSUSHI, TSUTSUI KOYO
Format:	Patent
Sprache:	eng
Schlagworte:	CHEMISTRY COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM,CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THERARE-EARTH METALS INORGANIC CHEMISTRY METALLURGY
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Beschreibung
Zusammenfassung:	PURPOSE:To continuously and stably produce an alpha-type gypsum hemihydrate having high purity, by converting a slurry of gypsum dihydrate to alpha-type gypsum hemihydrate by hydrothermal treatment under pressure, cooling the resultant slurry of alpha-type gypsum hemihydrate in pressurized state, separating the solid from the liquid under normal or reduced pressure and drying the product. CONSTITUTION:A slurry of gypsum dihydrate 1 and a crystallization medium 2 are mixed in a mixing tank 3, transferred to a reaction tank 6 through a heat-exchanger 5 with a pressure pump 4 and converted to alpha-type gypsum hemihydrate by hydrothermal treatment under pressure at >100 deg.C. The slurry of alpha-type gypsum hemihydrate extracted from the reaction tank 6 is transferred to the heat-exchanger 5 keeping the pressurized state and cooled to