The impact of bleaching on the yield of softwood kraft pulps obtained by high alkali impregnation: Bleaching and high alkali impregnation impact
2022 (English)In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 37, no 4, p. 593-608Article in journal (Refereed) Published
Abstract [en]
High alkali impregnation (HAI) increases the total yield of softwood pulps following kraft cooking. This yield improvement is also maintained after oxygen delignification. This study evaluates how bleaching with either chlorine dioxide or hydrogen peroxide affects the final yield of samples obtained with standard and HAI. The chemical composition, viscosity, brightness, mechanical and morphological properties were studied. Compared to cooking after standard impregnation the yield improvement achieved by HAI was preserved in both types of bleaching sequences (2 % units for chlorine dioxide and 4 % units for hydrogen peroxide). The introduction of charged groups into the cellulose fibers was higher with hydrogen peroxide bleaching than with chlorine dioxide however, no significant impact was seen on the swelling or mechanical properties. The brightness was higher for the pulps bleached with chlorine dioxide compared with hydrogen peroxide. Hydrogen peroxide bleaching resulted in similar brightness development for both standard and HAI. Fibers bleached with chlorine dioxide had the highest curl index (16-17 %) compared to the fibers bleached with hydrogen peroxide (15 %). © 2022 the author(s)
Place, publisher, year, edition, pages
De Gruyter Open Ltd , 2022. Vol. 37, no 4, p. 593-608
Keywords [en]
brightness, curl index, fiber charge, morphology, tensile index, Cleaning, Delignification, Fibers, Hydrogen peroxide, Impregnation, Kraft pulp, Luminance, Oxidation, Softwoods, Alkali impregnation, Curl indices, Fibre charge, Hydrogen peroxide bleaching, Kraft cooking, Softwood kraft pulps, Softwood Pulps, Total yield, Yield Improvement, Bleaching
National Category
Paper, Pulp and Fiber Technology
Identifiers
URN: urn:nbn:se:ri:diva-60545DOI: 10.1515/npprj-2022-0035Scopus ID: 2-s2.0-85138856693OAI: oai:DiVA.org:ri-60545DiVA, id: diva2:1704666
Note
Funding statement: The authors gratefully acknowledge the STFI Intressentförening and Södra Forskningsstiftelse for financial support. The Knut and Alice Wallenberg Foundation, the WWSC Program and the Wood and Pulping Chemistry Research Network (WPCRN) at KTH are gratefully acknowledged for financial support for Dr. Sevastyanova.
2022-10-192022-10-192023-07-06Bibliographically approved