摘要 |
A process for oxidizing a sulphite-ion-containing and/or hydrogen-sulphite-ion-containing aqueous solution in the presence of lime, preferably in wet flue-gas desulphurisation. In the process, lime, preferably calcium carbonate, is added to at least a part of the aqueous solution, and this part of the solution is then contacted with an oxygen-containing gas, such as air, before any precipitation of calcium sulphite has occurred. The oxygen-containing gas should be blown into the solution within 1 min of the addition of lime, preferably within 30 s, and most preferred within 5 s. It is further preferred that the solution be vigorously agitated, e.g. by means of a stirrer or a pump, when the process is implemented. The added lime should have a minimal particle size, and the average particle size preferably should not exceed about 30 mu m. It is preferred that the process be implemented at a temperature of about 40-60 DEG C. |