PROCESS FOR AIR OXIDATION OF AQUEOUS SOLUTION CONTAINING SODIUM SULFIDE WITH COUNTER-CURRENT PACKED COLUMN AND APPARATUS THEREFOR

PURPOSE:To perform oxidation of white liquor, etc., with an inexpensive apparatus having a simple structure with low electric power consumption, under normal pressure, by counter-currently contacting white liquor, etc., with air in an oxidation column furnished with a gas-liquid contacting stage composed of a packed bed and a chimney tray. CONSTITUTION:The upper part of an oxidation column 3 is provided with at least one stage (two stages in the figure) of a gas-liquid contacting stage composed of a combination of a packed bed 4 packed with a filler to promote the gas-liquid contact and a chimney tray 5 placed below the packed bed. A white liquor feeding pipe and an exhaust pipe are connected to the column top and a black liquor discharge pipe is connected to the column bottom. An air feeding pipe 10 is connected to the upper part of a black liquor reservoir 8 of the column bottom and a white liquor discharge pipe 11 is connected to the chimney tray of the lowest stage. A black liquor ejection part 7 is placed between the white liquor discharge pipe and a connecting part of the air feeding pipe 10. The carbon dioxide gas in the air is absorbed in the shower of the black liquor and the falling white liquor is oxidized by contacting with the ascending flow of the treated air.