| 摘要 |
NOx-containing exhaust gases arising in the manufacture of fertilisers by digestion of raw phosphates with nitric acid are removed by adsorption in a scrubbing fluid. For this purpose, the exhaust gases are scrubbed in a scrubbing stage with a circulated ammonium nitrate solution of which the concentration is held at values from 5 to 30 % by weight and the pH is held at values from 3 to 7 by addition of ammonia and the temperature is at most 40 DEG C. The ammonium nitrate solution laden with NOx is heated to at least 55 DEG C in a regeneration stage, cooled again to the temperature of the scrubbing stage after it has left the regeneration stage, and at least partially recycled to the latter. <IMAGE> |
