Thermochemical Process for Utilization of Gypsum and Pyrite Wastes

combustion flue gas desulfurization (FGD) using lime or limestone are the primary processes employed to reduce sulfur dioxide (SO 2 ) emission from coal combustion. However, these processes generate voluminous solid wastes, i.e., pyrite and gypsum, that are usually landfilled, occupying thousands of acres of land and creating serious land and water pollution problems due to the release of acids and toxic substances. A thermochemical process has been developed for the combined utilization of gypsum and pyrite wastes by converting them into useful products such as lime, sulfur, and iron, as shown in Figure 1.