Treating effluent gas contg. sulphur di:oxide - by scrubbing with sodium aluminate soln. to form aluminium hydroxy-sulphite, and oxidising this to aluminium sulphate

摘要

In removing SO2 from SO2-contg. effluent gases, the gas is first contacted with 1-15 wt.% aq. Na aluminate soln. in a suitable gas/liq. contact unit, esp. a venturi scrubber, such that at least a greater part of the SO2 is absorbed. The SO2 reacts with the aluminate to form Na sulphire and Al hydroxysulphite. The latter is sepd. and contacted with a suitable oxidising agent, esp. air, to form Al sulphate. The remaining Na sulphite can be recovered and opt. oxidised to Na sulphate. The process is esp. useful for treating flue gases from coal-burning furnaces and boilers, which has a high SO2 content and must be treated to prevent atmospheric pollution. The process is economical to operate and gives commercially useful prods. (Al sulphate, Na sulphate or sulphite) directly.