Patent ID: 8920603

Claim:
A process of bleaching pulp derived from an alkaline pulping process, said process comprising three chlorine dioxide stages D0, D1, and D2, wherein the chlorine dioxide charges based on the total chlorine dioxide charge in a) D0 is from 40 to 60%; b) D1 is from 30 to 55%; c) D2 is from 4 to 20%, wherein the pulp has a hexenuronic acid content after the D1 stage and prior to the final D2 bleaching stage from about 1 to about 80 mmol/kg dry pulp, wherein the final chlorine dioxide stage D2 is performed at a pH from 2 to 3.5, and wherein said process further comprises an oxygen-containing peroxide stage OP between the D0 and D1 stages.