| 摘要 |
PROBLEM TO BE SOLVED: To provide a producing method ofα-gypsum hemihydrate by which large crystals can be obtd. at a low cost and large crystals can be obtd. Just after the production process is started. SOLUTION: This producing method consists of a seed crystal ageing process to keep a source slurry 24 comprising gypsum dihydrate, water and habit modifier in a reaction tank 12 under pressure to produce a seed crystal 251, and anα-gypsum hemihydrate growing process to further add the source slurry 24 to the reaction tank 12 and to grow the grain size of the seed crystal 251 to produce a-gypsum hemihydrate by pressurizing the tank 12 and keeping its pressure.
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