| 摘要 |
Plaster constitutes 10-60 wt.% of the total compsn., and comprises dihydrate plaster converted through crystallisation from hemihydrate plaster, and in the form of tiny bars with a ratio of length to width of approximately 10-1:1, and an average particle size of 0.4 x 2 micrometres. - The crystallisation process involves alpha-type hemihydrate plaster crystallised during the input of water to dihydrate plaster at pH 1.0 - 4.0. The plaster crystals involved can have sizes in varying quantities, where the majority are less than or equal to 2 micrometres and the minority having a size ranging from less than or equal to 0.3 micrometres to less than or equal to 0.5 micrometres. |
