Study on the Extended Delignification of Plantation Eucalyptus Wood

Four Modified kraft (extended delignification) pulpings of plantation eucalyptus wood were carried out in laboratory. The results demonstrate that modified kraft pulping has higher pulping selectivity than conventional kraft pulping. Modified kraft pulping can produce very low Kappa number pulp with good pulp strength. Compared with the conventional kraft pulp, the Kappa number of modified kraft pulp of eucalyptus wood is 5～6 units lower, but its viscosity is more than 2.8 mPa·s higher. Modified kraft pulp has higher yield and lower rejects than its corresponding conventional kraft pulp. However, due to the slow reaction, modified kraft pulping needs greater H_factor value than conventional kraft pulping to achieve a given Kappa number.