Sulphur dioxide removal from gases as sulphate by scrubbing - with absorbent and catalyst in aq. liquid phase, for rapid reaction

摘要

In the removal of SO2 from gases, e.g. waste and combustion gas from the foundry, chemical and power industries by intensive multi-stage, counter-current scrubbing with a sprayed aq. soln. or suspension (I) in the presence of O2, (I) contains NH3, MOH, MCl and/or M2CO3 (in which M is NH4, an alkali metal or the equiv. of an alkaline earth metal) as reagent (II) and Cu, Ni, Co, Fe and Mn or their oxides, pref. in powder form, mineral acid salts or ammonium complexes as catalyst (III), so that sulphate is synthesised rapidly from SO2, O2 and H2O in the liquid aq. phase and generally another substance (IV) results at the same time. Pref. (II) is a chloride and (IV) is HCl, which can be neutralised with a hydroxide or carbonate, and recycled. (II), (III) and/or the neutralising agent can be industrial waste prods. The catalyst is used in the aq. liquid phase in a temp. range below the b.pt. The process is rapid and flexible, allowing the prodn. of various by-prods. as required.