To obtain an α-hemihydrate gypsum which is recyclable as a raw material for a gypsum board by easily separating a waste gypsum board into a gypsum component and a base paper component.
The collected waste gypsum boards are subjected to wet heat-treatment under pressure without being pulverized. This enables easy and complete separation of the waste gypsum boards into the gypsum component and the base paper component. The gypsum component is converted into α-hemihydrate gypsum with a reduced specific surface area and is effectively recycled as the raw material for manufacturing gypsum building materials such as the gypsum board. Meanwhile, the paper component is effectively recycled as waste paper or applied to agricultural usage, or the like.
COPYRIGHT: (C)2005,JPO&NCIPI
Yoshiyuki Kawamura
Kozo Akai
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| JP11278891A |
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