Abstract: Effects of water-plaster ratio, stirring rate, stirring time and water temperature on the mould gypsum performances of setting time, strength, water absorption were studied through contrast tests, then the mechanisms were investigated by SEM XRD.The result shows that: the optimized conditions are plaster-water percentage of 65%-70%, stirring speed of 400-500 r/min, stirring time of 2-3 min, water temperature of 25-30 ℃;the degree of crystallinity and crystal morphology of the hardened mould gypsum are influenced by all of the four processing parameters.

Key words: technological condition;mould gypsum;setting time;strength;water absorption