Process for stack gas treatment

摘要

A wet process for stack gas treatment wherein the stack gas is scrubbed with a suspension containing calcium hydroxide and/or calcium carbonate to remove sulfur oxides from the gas, characterized in that (1) air or oxygen-containing gas is supplied to the gas scrubber so as to oxidize at least 18% of the sulfur oxides absorbed by the scrub liquid to gypsum, and then part of the gypsum from the gypsum-containing scrub liquid partly taken out is recycled to the scrubber, or (2) part or whole of the scrub liquid is taken out from the scrubber into an oxidizer, where it is oxidized with the supply of air or oxygen-containing gas, and, after the oxidation, part of the scrub liquid from the oxidizer is recycled to the scrubber, whereby at least 18% of the sulfur oxides absorbed from the gas by the scrub liquid is oxidized to gypsum.