Improving Bleached Pulp Yield and Paper Strength Properties of Eucalyptus Through Integrating Kraft Pulping to High Kappa Number and Oxygen Delignification

摘要

This study examines the potential for improving bleached pulp yield and paper strength properties of eucalyptus through integrating kraft pulping to high kappa number and oxygen delignification. It was found that, the higher kraft kappa number selected, the less unbleached pulp yield loss and hexenuronic acid (HexA) formation obtained. Compared to the case of KP (kappa number = 13.4)-O-(DQ)P, 1.2% and 3.2% increase in bleached pulp yield of eucalyptus were obtained for the cases of KP (kappa number = 28.2)- and KP (kappa number = 39.9)-O-(DQ)P while reached the same brightness of about 85% ISO. But the active chlorine charge (ACC, ClO_2) for KP (kappa number = 39.9)-O-(DQ)P is three times more than those cases of KP (kappa number = 28.2)- and KP (kappa number = 13.4)-O-(DQ)P. Moreover, the tensile and burst index at the beating degree of about 41°SR for KP (kappa number = 28.2)-O-(DQ)P of eucalyptus were higher than that of other two cases by 15% and 12%, respectively. Therefore, considering the reduction of ACC and improvement of paper strength, the most suitable kappa number of fast-growing eucalyptus kraft pulp used in the process of KP-O-(DQ)P is about 28.