Displacement washing of TEMPO-oxidized softwood kraft pulp: Effects of change in fiber properties
Journal article, 2013

Bleached softwood kraft pulp fibers were treated using TEMPO oxidation at two different dosages of NaClO. A batch of non-oxidized reference pulp was also prepared with a concentration of the tracer (Na) similar to the oxidized batches. A total of 15 washing experiments were conducted and the dispersion model was used to characterize washing behavior. TEMPO oxidation resulted in a major increase in the amount of carboxylate groups in the pulps and a considerable decrease in fiber/particle size in relation to the reference pulp fibers. Oxidized fibers also had less fiber curl than reference fibers. Water retention values were greater in the oxidized pulps and the oxidized fibers exhibited major swelling during the washing operation, while reference fibers had only minor swelling. The amount of sodium in the filter cakes after washing corresponded to the amount of carboxylate groups in the pulps. Swelling of oxidized pulp fibers needs to be considered in order to describe filtration and washing. The average specific filtration resistance for all pulps in this study was in the order of 10(10)-10(11) m/kg, i.e. moderately easy to filter. The most oxidized pulp had the highest average specific filtration resistance and the lowest value for the estimated effective longitudinal dispersion coefficient, in agreement with theory.

sodium

water retention value

softwood kraft pulp

Displacement washing

TEMPO oxidation

Author

Fredrik Wernersson Brodin

Chalmers, Chemical and Biological Engineering, Forest Products and Chemical Engineering

Yogesh Sonavane

Aalto University

Maria Sedin

Innventia

Nordic Pulp and Paper Research Journal

0283-2631 (ISSN) 2000-0669 (eISSN)

Vol. 28 3 366-376

Subject Categories

Paper, Pulp and Fiber Technology

DOI

10.3183/NPPRJ-2013-28-03-p366-376

More information

Latest update

9/6/2018 1