WHITE LIQUOR OXIDATION FOR BLEACH PLANT USE

摘要

White liquor (14) is treated with oxygen (13) so as to oxidize all of the sulfur forms within the white liquor to sulfates. This allows the oxidized white liquor to be used in place of caustic in a cellulose pulp bleach plant. To treat cellulose pulp, a first stream of white liquor (14) may be oxidized incompletely (14), and then split into second (15) and third streams (16) of roughly equal volume. The second stream (15) is used for oxygen delignification (20), and third stream (16) is further oxidized (18) to convert all sulfur forms to sulfates, and then is used in the bleach plant. Air or substantially pure oxygen may be used as the oxidizing chemical, and oxidization (12) may take place catalytically or non-catalytically.