| 摘要 |
<p>In the removal of S dioxide from a gas by absorption in an aq. Na sulphite/bisulphite soln. and regeneration of the soln. by evapn., to form a gas rich in S dioxide and a solid consisting mainly of Na sulphite, for the prepd. of a fresh absorption soln., (part of) the evaporated soln. is mixed with NaOH and/or Na carbonate and cooled to crystalline Na sulphite hydrate, which is sepd. and recycled, whilst the residual liquor is rejected. The concn. of soluble impurities, esp. Na thiosulphate, NaCl and Se, in the absorption soln. and the loss of Na ions are kept low. The corrosive action of the soln. is also reduced.</p> |
