Comparison of the Brightening Response Between Juvenile and Mature Black Spruce Fibers, 2001 Pulping Conference Proceedings

D. Mancosky, L. A. Lucia, G. Goyal, R. Hanna--The bleachability of pulp is an important criterion for the success of a bleachable-grade manufacturing pulp mill. A pulp that is difficult to bleach can result in higher chemical and capital cost or a lower final product quality. Increased bleaching chemicals may also negatively influence pulp strength. The current work represents several novel results for the brightness response of laboratory-generated juvenile and mature pulp in oxygen and peroxide bleaching. The mature and juvenile pulps were manufactured by strategically separating the top eight-foot section from a northern black spruce tree from the pulpwood. While the initial brightness out of the digester is about the same, the juvenile wood has a lower brightening response than the mature wood. Samples were cast into sheets and tested for TAPPI brightness, metals, lignin NMR, kappa, fiber length, fiber coarseness, Klason lignin, viscosity, and zero-span tensile. Factors that were varied in this experiment were type of bleaching, chelation, and extractive removal. The goal of this project was to characterize the brightness differences and assign a chemical basis for this brightness difference.