Oxygen delignification of populus kraft pulp and effect of peroxyacid pretreatment. I. Oxygen delignification of populus kraft pulp

Oxygen delignification of populus kraft pulp is studied. The results show that up to about 50% residual lignin in the pulp was removed under appropriate delignification conditions and pulp brightness exhibited about 20 percent increases with very little loss in viscosity. It was also found that the selectivity of oxygen delignification may be optimized with the appropriate combination of alkali charge, temperature and time.