| 摘要 |
In patent application P 3519681.5, a process is described for scrubbing water treatment and recovery of valuable materials in the simultaneous removal of SO2 and NOx from flue gas, in which in the oxidizer sulphuric acid and air are added so that a commercial end product is present as gypsum after the filtration. It has now surprisingly been found that if the pH is sufficiently greatly reduced to the strongly acidic range by addition of sulphuric acid, in the range of pH below 3, ironIII is reduced to ironII. The conversion of ironIII to ironII is integrated in the scrubbing water treatment and at a defined point a pH-reducing medium is added, preferably sulphuric acid, which reduces the scrubbing liquid to a pH below 3, preferably around 1.5.
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