The characterization system for dewaterability of flue gas desulfurization(FGD) gypsum

including sludge specific resistance of filtration(SRF)

capillary suction time(CST)

cake moisture content and average particle size

was constructed based on the analysis of microstructure

composition and dewaterability of FGD gypsum from coal-fired power plants. The influences of initial FGD gypsum mass concentration

the type and the dosage of polyacrylamide(PAM) on the conditioning performance of FGD gypsum were investigated. The results indicate that

the higher initial mass concentration of FGD gypsum led to better dewaterability after conditioning

but too high mass concentration would cause blockage of the pipeline and reduce the service life of equipments. After being conditioned by the selected PAM at the dosage of 0.20 mg/g

the SRF

CST and the moisture content of the FGD gypsum decreased to 1.21×10~8 s~2/g

99.2 s and 25.6%

respectively

and the average particle size of the FGD gypsum increased to 125.2 μm. The quality of the FGD gypsum after conditioning and dewatering could satisfy the requirements of Flue Gas Desulfurization Gypsum(GB/T 37785—2019).