| 摘要 |
PROBLEM TO BE SOLVED: To provide a method of manufacturing gypsum dihydrate effective for efficiently hydrating a II-type gypsum anhydride, which is hardly hydrated for forming gypsum dihydrate. SOLUTION: A gypsum anhydride containing the II-type gypsum anhydride is brought into contact with a water solution containing an alkali sulfate or ammonium sulfate at a temperature of 35°C or lower, after being pulverized so as to have 50% accumulative diameter of 3μm or smaller. Also, a filtrate and/or washing drain can be used as a part of the water solution containing an alkali sulfate or ammonium sulfate, and the obtained gypsum dihydrate can be reutilized as a raw material for gypsum boards, that is a gypsum raw material for a gypsum board manufacturing facility, without being dried. COPYRIGHT: (C)2009,JPO&INPIT
|
