Effect of primary fines on cooking and TCF-bleaching
1999 (English)In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, Vol. 14, no 3, 209-213 p.Article in journal (Refereed) Published
When pulp is separated into fibre fractions on the basis of size, the smallest fraction obtained is called fines. Primary fines are found in cooked pulp not subjected to beating and secondary fines are created in the cause of beating. Fines have higher lignin and metal ion contents than the fibre fractions of the pulp. In this study, the effect of the primary fines on cooking and bleaching has been investigated. The results showed that removal of the primary fines during cooking had no positive effect on the delignification. The pulp viscosity at a certain kappa number and the H-factor to reach this kappa number were the same, regardless of whether or not the primary fines were present. However, the primary fines had a profound effect on bleaching when a QP sequence was used. An increase of approximately 2 ISO-brightness units was obtained by removing the primary fines prior to bleaching. Pulps with and without primary fines showed no significant difference in metal ion content or light scattering coefficient. The light absorption coefficient was, however, higher in the pulp with fines. The improved bleachability of the pulps without fines was therefore probably caused by differences in lignin content and in the lignin structure rather than by differences in metal ion content.
Place, publisher, year, edition, pages
1999. Vol. 14, no 3, 209-213 p.
(primary) fines, cooking, bleachability, kraft pulp, lignin, SURFACE MATERIAL, KRAFT FIBERS, SPRUCE, PARTS
IdentifiersURN: urn:nbn:se:kth:diva-12968ISI: 000082959800005OAI: oai:DiVA.org:kth-12968DiVA: diva2:319922
QC 201005202010-05-202010-05-202010-05-20Bibliographically approved