Influence of the conditions during birch kraft cooking on unbleached brightness, and on ECF- and TCF-bleachability
2004 (English)In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, Vol. 19, no 3, 309-317 p.Article in journal (Refereed) Published
The influences on ECF and TCF bleachability of the hydroxide ion, hydrogen sulphide ion and sodium ion concentrations as well as of the amount of dissolved wood components (DWC) in a birch kraft cook were investigated. The pulping was carried out using a so-called constant composition cooking technique, where a high liquor-to-wood ratio enables an almost constant concentration of the cooking chemicals during the entire cook. This cooking method also renders possible to vary each cooking variable separately. The pulps were oxygen-delignified and bleached in a D(EOP)DD and a Q(OP)Q(PO) sequence. The presence of DWC caused a significant rate increasing effect on the delignification. An increase in hydroxide ion concentration, an increase in hydrogen sulphide ion concentration or a decrease in sodium ion concentration improved both the ECF and the TCF bleachability, but the DWC had no significant effect on the bleachability. Further a correlation was found between the bleachability and the brightness of the oxygen-delignified pulp.
Place, publisher, year, edition, pages
2004. Vol. 19, no 3, 309-317 p.
birch, bleachability, dissolved wood components, ECF, hydrogen sulphide ion concentration, hydroxide ion concentration, kraft pulping, light absorption, sodium ion concentration, TCF, hexeneuronic acid groups, kappa-number, pulp, xylan, softwood, lignin
IdentifiersURN: urn:nbn:se:kth:diva-23824ISI: 000224636500005ScopusID: 2-s2.0-6344235478OAI: oai:DiVA.org:kth-23824DiVA: diva2:342523
QC 20100525 QC 201111012010-08-102010-08-102011-11-01Bibliographically approved