Research on oxygen delignification process with eucalyptus kraft pulp

The four processes of one stage and two stage oxygen delignification with screen and unscreen pulp of eucalyptus kraft pulp were compared. The results show that two stage oxygen delignification with unscreen pulp has the best effects in delignification,having the highest delignification rate and brightness. The lignin removal rate of the two stage oxygen delignification with unscreen pulp can reach 52.7%,the brightness can reach 51.2%ISO and the viscosity 734.4ml/g. The fiber analysis results show that average fiber length,fiber coarseness and length-width ratio of two stage oxygen delignification with unscreen pulp are 0.78mm,6.1 mg/100m and 54.4 respectively. This lays a good foundation for the following bleaching.