To produce an inexpensive gypsum board having high strength and water resistance by using α-hemihydrate gypsum.
A gypsum board is produced by a method wherein α-hemihydrate gypsum obtained as a byproduct when phosphoric acid is produced by a wet phosphoric acid producing method is hydrated to form a gypsum dihydrate and this gypsum is dried and baked to obtain a β-hemihydrate gypsum which is, in turn, slurried to obtain a β-hemihydrate gypsum slurry (A) and this slurry (A) is applied to a lower board raw paper and an upper board raw paper, and the α-hemihydrate gypsum obtained as a byproduct is dried and alkali is added thereto to form an α-hemihydrate gypsum slurry (B) which is, in turn, poured on the lower board raw paper and the upper board raw paper is integrated therewith, and the whole is cured and dried.
DOI KIYOTO
YOSHINO TADASHI
ABE KOJI
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