Abstract: In order to lower the sulfuric content of the offgas from a smelter reactor in which iron oxide is reduced to molten iron, in the presence of sulfur contaminants, a sufficient amount of a source of zinc is included in the charge to the reactor that the combined weight of the zinc source and the iron oxide source contains at least about 0.6% Zn (calculated as elemental zinc), on a dry weight basis. The temperature of the offgas is maintained at or above approximately 700.degree. C. Vaporized zinc, present in the offgas, binds with sulfur in the offgas to precipitate solid ZnS. After removal of the ZnS, the offgas may have a sulfuric content below 50 ppm by volume of H.sub.2 S equivalent. Suitable sources of zinc include blast furnace dust, electric arc dust, basic oxygen furnace dust, zinc calcine, and zinc sinter.

Abstract: Dolomite which has been used to remove sulfur and/or sulfur-containing compounds from gases by chemical reactions therewith is regenerated by passing through the spent dolomite an oxidizing gas selected from oxygen, CO.sub.2 and H.sub.2 O at temperatures between about 1500.degree. F. and the temperature at which the dolomite becomes unreactive.