Process for removing SO2 from gases which contain it, with direct production of elemental sulfur

摘要

A wet process of regenerative type for removing SO2 contained in combustion gases is disclosed, which is characterized in that SO2 is caused to be absorbed by a diluted aqueous solution of BaS, with a mixed precipitate of elemental S, BaSO3 and BaSO4 being formed by the consequent reactions. Sulfur is extracted from the precipitate --recovered by filtration -- by using a solution of (NH4)2S: the resulting polysulfide is distilled, with pure elemental S and the solution of (NH4)2S to be recycled, being obtained. The residual mixture of BaSO3 and BaSO4 remaining after sulfur extraction is reduced with coal in a high temperature furnace, in order to obtain BaS to be recycled, as an aqueous solution, to the SO2 absorption step.