Different refractory fillers were added to the gypsum

and the flowability

time

wet strength of gypsum powder

strength after calcination

linear shrinkage and microstructure of the gypsum slurry were tested and analyzed at the same water-paste ratio.The results reveal that coal gangue and diatomaceous earth are simultaneously incorporated into the gypsum cast powder

then

after calcination the gypsum grains are well overlapped

compacted and the gypsum molding have the good strength.The flow diameter of gypsum slurry is 90 mm

the initial time of 7 min with the final time of 17 min

the flexural strength of 2.02 MPa

the compressive strength of2.3 MPa.After calcination the flexural strength is 0.458 MPa with the compressive strength of 1.07 MPa

and its linear shrinkage rate of 0.320% when the content of coal gangue is 20%and diatomite is 10%.