Effect of fibre properties on ozone bleaching of oxygen-delignified eucalypt kraft pulps at high consistency

An experimental rig was constructed for studies of ozone bleaching kinetics of oxygen-delignified kraft pulps at high consistency. The pulps were produced from E. regnans and E. globulus laboratory chips. The delignification curves (Kappa versus treatment time) of both pulps had similar slopes. The similarity between the delignification curves from ozonation of the two pulps with different fibre dimensions suggested that the heterogenous nature of the fibre wall may not be a dominant factor. The effectiveness of the delignification was slightly less when the ozone concentration in the inlet stream was increased from 0.6 to 2.0%. There appeared to be little difference in the stoichiometric ratio of the delignification of the two pulps.