Synthetic Gypsum | BuildingGreen
Jul 30, 2010· Synthetic gypsum, which is now used in about 30% of drywall, is a byproduct of coal-fired power plants. It is sometimes confused with fly ash—another coal combustion product that's been in the news recently—but the two have very little in common. Synthetic gypsum is also called flue-gas-desulfurization (FGD) gypsum.