Process for purifying a gas containing sulfur compounds

A process for purifying a gas containing hydrogen sulfide and sulfur dioxide in a molar ratio of H.sub.2 S to SO.sub.2 of more than 2 :

• 1, said gas being discharged from a sulfur production unit in which hydrogen sulfide is oxidized by means of molecular oxygen or sulfur dioxide in gas phase, comprising the steps of (a) contacting the hydrogen sulfide and sulfur dioxide containing gas with molten sulfur or with an organic solvent, thereby producing sulfur by reaction between said hydrogen sulfide and said sulfur dioxide, and recovering separately said produced sulfur and a gas of relatively higher H.sub.2 S to SO.sub.2 molar ratio, (b) passing the gas recovered from step (a) over a solid zinc oxide containing mass at 300.degree.-800.degree. C. for absorbing hydrogen sulfide and discharging the resultant H.sub.2 S depleted gas, (c) periodically interrupting the contact of the gas with said mass and passing over the same at 400.degree.-1200.degree. C. a gas containing molecular oxygen produced by burning hydrogen sulfide with an excess oxygen containing gas, thereby regenerating the mass, and recovering an SO.sub.2 containing effluent gas, and (d) reacting said effluent gas with hydrogen sulfide in said sulfur production unit thereby producing additional sulfur.