| Abstract |
A process for calcined-gypsum production which attains a reduction in the amount of water to be mixed and does not prolong setting time. A raw-material gypsum is calcined after a carboxylic acid is incorporated thereinto, whereby calcined gypsum can be obtained which necessitates a smaller amount of water to be mixed therewith and needs no prolonged setting time. Even when recycled gypsum, which leads to an increase in the amount of water to be mixed, is used in a large amount as a raw material for gypsum, the calcined gypsum produced by the process is reduced in the amount of water to be mixed therewith and needs no prolonged setting time. Consequently, ordinary gypsum boards can be produced without lowering the productivity thereof. |