Water resistant block from desulfurization gypsum

The purpose of this study is to prepare water resistant block from flue gas desulfurization gypsum [FGD]. A water resistant agent prepared from granulated blast-furnace slag (GBFS), high calcium fly ash (HCFA) and some additives, was mixed with calcined desulfurization gypsum to form modified gypsum powder which is used to produce water resistant block. The optimized proportioning was obtained by using orthogonal test. The softening coefficient of the product prepared is over 0.80 with thermal conductivity coefficient of 0.15 W/(m K). The water resistance mechanism of this product was investigated by SEM and XRD.