YU171271

1308746 Removal of mercury and selenium from gases OUTOKUMPU OY 2 July 1971 [3 July 1970] 31172/71 Heading C1A Mercury is removed from gases by washing with circulating sulphuric acid of concentration 80-98% by weight at 70-250‹ C., the water vapour pressure of the wash solution in the tower being substantially the same as the partial pressure of the water vapour in the gas to be washed, and the resulting solid which contains mercury is separated from the circulating acid. The gas stream may also contain selenium which is also removed. Preferably the mercury containing gases are subjected to dust removal prior to the washing with acid. It is important that the humidity of the gases does not dilute the wash solution. The solid product after separation from the circulating acid may be washed with water to remove sulphuric acid and any other metal salts which may be present thus concentrating the mercury and selenium in the residue.