Removal of sulphur dioxide from stack gases - by reaction with ammonia, evaporation reaction of the liq. with alkali sulphides to give hydrogen sulphide then pptn of sulphur from gases

摘要

Parent patent described a process in which waste gas is contacted with aq. ammonia, the salts produced are heated to vaporise at least one third of the SO2, the effluent liquid is reacted with barium sulphide to produce H2S and barium salts and the H2S is reacted with the SO2. In this addition patent the BaS is replaced with alkali sulphides (K2S, Na2S) which are more readily disposable.