Paraserianthes falcataria is a hardwood species suitable for making good quality kraft pulp with a high yield. The species is used as a raw material in one of the pulp mills in Bangladesh using soda process. Consequently, the pulp yield and quality are poor. To overcome these drawbacks this study has been conducted.

The study shows that anthraquinone (AQ) has a positive effect both in soda and kraft pulping of P. falcataria. AQ addition by 0.05% can reduce the alkali charge by 5 per cent points and increase the pulp yield by about 4 per cent points in soda pulping. The yield becomes equivalent to the kraft counterpart. The use of 0.15% AQ further increases the pulp yield to surpass the kraft. But the gain in yield with 0.15% AQ addition is not as remarkable as with the lower dose (0.05%). An addition of AQ in kraft pulping also increases the yield, but not to the extent as in soda pulping. It is also observed that the pulp quality improves by the addition of AQ both in soda and kraft pulping. The soda-AQ pulp is almost equivalent to the kraft counterpart, with only 6% lower value in tearing strength at a particular tensile strength.