Extended Delignification of Mature and Plantation Eucalypt Wood, 1994 International Pan Pacific Conference Proceedings

G. M. Irvine, N. B. Clark

Laboratory kraft pulping trials were carried out to characterize the effects on Australian mature and plantation eucalyptus of each of four key factors of extended delignification. The application of three of the key factors (level alkali profile, high initial hydrosulfide ion concentration and low dissolved lignin concentration) improved the tear strength of the eucalypt pulps at a given Kappa number. However, the beneficial effect of the fourth key factor (a low cooking temperature) was limited to a small increase in pulp yield. Laboratory-scale simulations of modified continuous processes produced pulps with Kappa numbers as low as 10, with tear strengths and yields equal to those of conventional pulps with Kappa numbers of c. 20. Simulations of modified batch processes produced pulps with high strengths down to Kappa numbers as low as 8, but with yields that were not greater than those of conventional pulps prepared at the same Kappa numbers.