Patent ID: 6776876
Filing Date: 2004-08-17
Classification: D21C

Abstract:
A method of treating chemical cellulose pulp produced by alkaline delignification and having a kappa number of under 24, having hexenuronic acid therein, comprising the steps of:(a) treating chemical cellulose pulp produced by alkaline delignification having a kappa number under 24 and at a solids consistency of between 0.1-50% by treating the pulp at a temperature over 85Â° C. and at a pH between about 2-5 for sufficient time to remove at least 50% of the hexenuronic acid and to reduce the kappa number by at least 2 units; and (b) bleaching the chemical cellulose pulp produced by alkaline delignification having a kappa number under 24 in at least one bleaching stage.