Utilization of by-product of gas desulfurization with semi-dry process for Portland cement retarder

The effects of the semi-dry flue gas desulfurization residues mainly containing CaSO3 on the cement setting time and mechanical property were studied.The experiments revealed that the desulfurization residues could retard the setting time of the selected Portland cement,and the effect was stronger than using gypsum as setting retarder.However,with the desulfurization residues instead of gypsum as setting retarder,the mechanical strength of the cement might be decreased.In addition,because the composition of desulfurization residues varied irregularly,the adding proportion had to be regulated in time when used as cement setting retarder.Therefore,it could be concluded that using the semi-dry desulfurization residues instead of gypsum as cement setting retarder was feasible in technology,but there was no notable advantage in the market.