Tremendous domestic reserves of gypsum and anhydrite constitute a potential source of raw material f i x sulfur-based chemicals. As in Europe today, calcium sulfate may become one of our principal raw materials for sulfuric acid. Several European acid plants are based on a process in which sulfur dioxide is freed from anhydrite by heating the latter with coke and shale to a sintering temperature (4). The sulfur dioxide is converted into acid and the clinker is used for portland cement.