OXYGEN DELIGNIFICATION AND D1(EOP)D2 BLEACHING OF MIXED PULP BLENDED BY PINUS MASSONIANA PULP, EUCALYPTUS PULP AND BAMBOO PULP

摘要

The mixed pulp blended by pinus massoniana pulp, eucalyptus pulp and bamboo pulp according to different proportions was sampled. Elemental chlorine free bleaching sequence, including oxygen delignification and D1(EOP)D2 bleaching process, was applied to bleach these mixed pulp samples. To investigate the bleaching results and to explore the feasibility of mixed pulp to be bleached to a certain brightness, can not only supplied experimental data of elemental chlorine free bleaching of mixed pulp, but also provided bases for pulping mills to optimize production line and save the production cost. The results indicated that mixed pulp could be bleached to at least 84.5% ISO brightness by oxygen delignification and D1(EOP)D2 sequences, even reached 87.1% ISO brightness, but the viscosity after bleaching decreased in an extent. And different proportions of these three kinds of pulp have some effects on bleaching results under the same bleaching conditions. Brightness of mixed pulp after the last bleaching stage increased with the increase of pinus massoniana pulp content.