The impact of bleaching on the yield of softwood kraft pulps obtained by high alkali impregnation : Bleaching and high alkali impregnation impact

Abstract: 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 %).

Location
Deutsche Nationalbibliothek Frankfurt am Main
Extent
Online-Ressource
Language
Englisch

Bibliographic citation
The impact of bleaching on the yield of softwood kraft pulps obtained by high alkali impregnation ; volume:37 ; number:4 ; year:2022 ; pages:593-608 ; extent:16
Nordic pulp & paper research journal ; 37, Heft 4 (2022), 593-608 (gesamt 16)

Creator
Esteves, Cláudia V. G.
Sevastyanova, Olena
Östlund, Sören
Brännvall, Elisabet

DOI
10.1515/npprj-2022-0035
URN
urn:nbn:de:101:1-2022112613064530252582
Rights
Open Access; Der Zugriff auf das Objekt ist unbeschränkt möglich.
Last update
15.08.2025, 7:27 AM CEST

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Associated

  • Esteves, Cláudia V. G.
  • Sevastyanova, Olena
  • Östlund, Sören
  • Brännvall, Elisabet

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