Desulfurization of waste gases containing hydrogen sulfide

A process for removing hydrogen sulfide from a gas containing it comprising treating the gas with an aqueous solution of at least one organic polybasic acid selected from the group consisting of oxalic acid, malonic acid, glutaric acid, adipic acid, maleic acid, fumaric acid, citraconic acid and phthalic acid and buffered by a base,

• a. the gas having a molar ratio of hydrogen sulfide to sulfur dioxide of at least about 2:1 and being brought into contact in finely divided form in a first absorption and reaction zone at a temperature of about 10 to 100.degree. C with the aqueous absorption solution buffered by the base to a pH of about 2 to 6, thereby to produce solid sulfur;
• b. the sulfur accumulating in solid form from the solution being removed from at least a component stream of the solution;
• c. the gas leaving stage (a) being heated to a temperature of about 700.degree. to 1000.degree. C, thereby converting the sulfur compounds present in the gas into sulfur dioxide and oxidizing any organic compounds present into carbon dioxide and water;
• d. SO.sub.2 -containing smoke gas from stage (c) being recycled to stage (a);
• e. the balance of the smoke gas component stream from (c) being treated in a second absorption stage (e) with the solution leaving stage (b) for the substantially quantitative absorption of SO.sub.2, and
• f. the SO.sub.2 -containing solution from stage (e) being recycled to stage (a).