Recovery of sulfur values from spent sulfuric acid

In the method for recovering sulfur values from spent sulfuric acid by decomposing it at elevated temperature in the presence of elemental sulfur to generate a sulfur dioxide-containing gas stream, the improvement which comprises:

• a. introducing spent sulfuric acid into a pool of molten sulfur maintained at temperature of at least about 250.degree. C, wherein said pool of molten sulfur furnishes both the reaction medium as well as the reductant for said sulfuric acid, to thereby generate a gaseous stream comprising sulfur dioxide, vaporous elemental sulfur, and water;
• b. cooling said gaseous stream comprising sulfur dioxide, vaporous elemental sulfur, and water to temperature above the melting point of the sulfur but below about 160.degree. C. to condense elemental sulfur therefrom, separating said condensed elemental sulfur and returning it to said pool of molten sulfur;
• followed by
• c. further cooling the gaseous stream from which elemental sulfur has been condensed to condense water therefrom, and separating the condensed water from the gaseous stream.