Pulping and bleaching OCC. Part Ⅰ: Delignification

摘要

This paper reports on the course of kraft pulping delignification of OCC (old corrugated containers) pulps in preparation for bleaching. An attempt was also made at direct oxygen delignification of OCC pulps, omitting the pulping process, however, this method was not feasible because after reaching kappa number of approximately 30, further delignification was very slow. The course of OCC pulping was compared with that of wood (birch and pine) and attempts were also made to carry out joint pulping of OCC pulps and wood chips. These attempts showed that OCC pulps, when pulped together with wood, are delignified at a similar rate as that observed during separate delignification.