Abstract: In accordance with the invention, gases containing sulfur dioxide are passed through a solution rich in ferric iron and containing barium chloride or calcium chloride. Sulfur dioxide is oxidized by the ferric ion to sulfur trioxide when then forms sulfuric acid in the water. The sulfuric acid reacts with the barium ion to form barium sulfate, while the ferric ion is reduced to the ferrous state. The barium sulfate is separated from the mother liquor by filtration and is then reduced to barium sulfide with a carbonaceous material or any reducing gas. Then, the barium sulfide is reacted with another portion of solution rich in ferric iron to form elemental sulfur, while the barium ion or calcium ion combines with the chloride ion to regenerate barium chloride or calcium chloride as the case may be. The resulting solution, after the sulfur has been removed, is now rich in ferrous iron.