Environmentally Friendly Pulping and Bleaching of Bagasse, 1998 Pulping Conference Proceedings

By maintaining the H-factor same, the addition of a small fraction of AQ during cooking of bagasse has helped reduce the kappa number of pulp by almost 40% of that of soda pulp. The oxygen delignification of soda and soda-AQ pulps under specified process conditions also reduced the kappa number by 45 and 49% of the original values for both pulps. However the loss in yield and strength properties during oxygen delignification was very marginal for both soda and soda-AQ pulps. Thus the reduced kappa number of

pulps not only decreased the demand of chemicals during bleaching but also the formation of chlorinated organics. The ECF bleaching of oxygen delignified pulps gave higher brightness as compared to the DED bleaching of soda and soda-AQ pulps. The effluent properties, COD, color and AOX were reduced significantly with the increased substitution of chlorine with chlorine dioxide in first stage and later stages of bleaching. A combination of oxygen delignification and DED bleaching would reduce the environmental load by 90% of that of CEH bleaching. So a pulp of higher brightness and comparable strength properties could be produced from bagasse by employing an environmentally friendly process of soda-AQ pulping followed by oxygen delignification and DED bleaching.