PER ACID BLEACHING OF KRAFT PULP

Abstract

Per acids may prove viable for use in ECF and TCF bleaching sequences.In the present study the peracetic acid was used as a delignifying agent . Peracetic acid was used to delignify the oxygen treated and untreated pulp in ECF & TCF sequences. A comparison was done between Peracetic acid delignification and conventional Oxygen delignification stage. The results indicates that the extent of delignification by Pa stage is lower than 0 stage. The 0 stage gives brightness, viscosity equivalent to Pa stage followed by Eop stage. However the COD load of 0 stage was found higher than Pa stage. P stage or D 9- stage used after Pa Eop stages improved the brightness by 14-20 points and after 0 Pa stages by 13-14 points with reduction in pulp viscosity by 14-20% and 30 % respectively.