The response of rajkoroi (Albizia richardiana King and Prain) wood for making
pulp in NS-AQ (Neutral Sulphite Anthraquinone), soda, soda-AQ and kraft pulping
processes was assessed by different alkali doses and pulping time. The temperature
was maintained at 170°C in all cases. Results showed that the species was not suitable
for making pulp in NS-AQ process. Pulps could be made in soda process but the
amount of uncooked material (rejects) was high. Addition of 0.1% AQ in soda liquor
gave better results in delignification. The species responded very well towards kraft
process. Bleachable grade kraft pulp was obtained even with 14% active alkali with a
pulp yield of 48.2%. The pulp yield of rajkoroi was
species widely used in pulp and paper mills of Bangladesh.
Hand sheets from soda, soda-AQ and kraft pulp of rajkoroi were made. The
physical strength properties likely tear, tensile and burst were evaluated. Kraft pulp
was superior to the pulp produced either in soda and soda-AQ processes but slightly
inferior to the pulp produced from commonly used hardwood species. The pulp of this
species could be blended with imported softwood pulp for making moderate quality
writing, printing and wrapping paper.