LUO Ting, GU Xingyong, CHEN Chao, DONG Weixia, GUO Qihuang
(Jingdezhen Ceramic Institute, Jingdezhen 333403, Jiangxi, China)

Abstract: The hemihydrate gypsum slurries mixed at normal temperature were pretreated by hydrothermal method at different temperatures before casting gypsum mould. Then, the rupture modulus and water absorption of dried gypsum mould were tested. The phase composition and growth of crystal and crystal morphology of the mould were also characterized. Then, the effect of hydrothermal method on the basic performance and microstructure of gypsum mould was discussed. The results indicate that hydrothermal pretreatment technology would promote the growth and increase the crystallinity of dihydrate gypsum crystalline of gypsum mould effectively. The crystal will grow longer and thinner with the increase of the hydrothermal temperature. The strength of gypsum mould prepared by the new process is obviously higher than by the traditional craft. And the water absorption didn’t decline, but rose a little.
Key words: hydrothermal method; gypsum mould; pretreatment; temperature