The use of calcium hydroxide as alkali source in peroxide bleaching of kraft pulp

A1 Originalartikel i en vetenskaplig tidskrift (referentgranskad)


Interna författare/redaktörer


Publikationens författare: Anders Strand, Ekaterina Korotkova, Juuso Hakala, Erja Lindstedt, Stefan Willför
Förläggare: Mid Sweden University
Publiceringsår: 2017
Tidskrift: Nordic Pulp and Paper Research Journal
Tidskriftsakronym: Nord. Pulp Pap. Res. J.
Volym: 32
Nummer: 3
Artikelns första sida, sidnummer: 444
Artikelns sista sida, sidnummer: 451
Antal sidor: 8
ISSN: 0283-2631
eISSN: 2000-0669


Abstrakt

The feasibility of replacing sodium hydroxide with calcium hydroxide in peroxide bleaching of kraft pulp was assessed. The bleaching experiments were carried out in small scale on two different starting pulps, with a preliminary study and a more narrow follow-up study. The preliminary study showed that the required amount of Ca(OH)(2) was quite low compared to NaOH. The follow-up study showed that the same brightness gain and decrease in yellowness as 1% NaOH were achieved with 0.25% Ca(OH)(2), which could result in savings of 80-85% on the cost of bleaching alkali. Replacing NaOH with Ca(OH)(2) resulted in similar optical and mechanical properties as the reference pulp. The concentration of total organic carbon in the bleaching waters was in the same size range with NaOH and Ca(OH)(2). This study indicates that alternative alkali sources can be used in the peroxide bleaching stage of kraft pulp.


Nyckelord

Alternative alkali, Brightness, Calcium hydroxide, Kraft pulp, Peroxide bleaching

Senast uppdaterad 2019-19-05 vid 06:11