NSSC pulping of fast growing trees

Neutral sulphite semichemical pulping (NSSC) of Schizolobium amazonicum (Paricá), a fast-growing Amazonian tree, was compared with that of Eucalyptus grandis (eucalypt), one of the most important wood sources for the Brazilian pulp industry, and with mixtures of both woods in different proportions (mix). Wood chips prepared from 7-year old trees were steamed, cooked using the NSSC process and defibered in a 12″ disc refiner in three stages. The paricá wood produced pulp of lower yield (75 %) than eucalypt (77 %) at 16 % sulfite/150 min/170 °C. The paricá and eucalypt pulps were bleached to about 68 and 74 % ISO brightness, respectively, by the QPFAS sequence. Paricá consumed more energy for refining in comparison with the eucalypt wood. The wood mix produced lower yield and brightness than the single species processed separately.