Sodium sulphite pulping of Scots pine under neutral and mildly alkaline conditions (NS pulping)

Saara Hanhikoski (Corresponding Author), Elina Warsta, Antero Varhimo, Klaus Niemelä, Tapani Vuorinen

Research output: Contribution to journalArticleScientificpeer-review

1 Citation (Scopus)

Abstract

Sodium sulphite pulping of Scots pine chips in the initial pH range of 7.5-9 was investigated at 180°C and 165°C (for 120-240 min), using chemical charges between 25 and 50% and anthraquinone (AQ) charges 0-0.2%. As a result, pulps with yields of 52-73% and kappa numbers of 35-106 were produced. Delignification was accelerated by higher Na2SO3 charges and temperatures, and by AQ addition, whereas the effect of initial pH was negligible. The high pulp yields at a given kappa number were attributable to high retention of hemicelluloses, especially that of galactoglucomannan. The relatively low viscosities of pulps were apparently caused by depolymerisation of cellulose by sulphite. The sulphonic acid groups in the pulps correlated well with the residual lignin content, although some sulphonation of polysaccharides may also be possible. The results indicate that pulping of softwood in buffer-free (without Na2CO3 and/or NaOH) sodium sulphite liquor may result in pulps with tailored characteristics.
Original languageEnglish
Pages (from-to)603-609
JournalHolzforschung
Volume70
Issue number7
DOIs
Publication statusPublished - 2016
MoE publication typeA1 Journal article-refereed

Fingerprint

Pulp
Sodium
Anthraquinones
Sulfonation
Delignification
Depolymerization
Sulfonic Acids
Softwoods
Lignin
Polysaccharides
Cellulose
Buffers
sodium sulfite
Viscosity
Acids
Temperature

Keywords

  • anthraquinone (AQ)
  • galactoglucomannan (GGM)
  • high yield pulp
  • lignin
  • neutral sulphite pulping (NS)
  • neutral sulphite semi-chemical pulping (NSSC)
  • sodium sulphite
  • softwood
  • sulphonic acid group

Cite this

Hanhikoski, Saara ; Warsta, Elina ; Varhimo, Antero ; Niemelä, Klaus ; Vuorinen, Tapani. / Sodium sulphite pulping of Scots pine under neutral and mildly alkaline conditions (NS pulping). In: Holzforschung. 2016 ; Vol. 70, No. 7. pp. 603-609.
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abstract = "Sodium sulphite pulping of Scots pine chips in the initial pH range of 7.5-9 was investigated at 180°C and 165°C (for 120-240 min), using chemical charges between 25 and 50{\%} and anthraquinone (AQ) charges 0-0.2{\%}. As a result, pulps with yields of 52-73{\%} and kappa numbers of 35-106 were produced. Delignification was accelerated by higher Na2SO3 charges and temperatures, and by AQ addition, whereas the effect of initial pH was negligible. The high pulp yields at a given kappa number were attributable to high retention of hemicelluloses, especially that of galactoglucomannan. The relatively low viscosities of pulps were apparently caused by depolymerisation of cellulose by sulphite. The sulphonic acid groups in the pulps correlated well with the residual lignin content, although some sulphonation of polysaccharides may also be possible. The results indicate that pulping of softwood in buffer-free (without Na2CO3 and/or NaOH) sodium sulphite liquor may result in pulps with tailored characteristics.",
keywords = "anthraquinone (AQ), galactoglucomannan (GGM), high yield pulp, lignin, neutral sulphite pulping (NS), neutral sulphite semi-chemical pulping (NSSC), sodium sulphite, softwood, sulphonic acid group",
author = "Saara Hanhikoski and Elina Warsta and Antero Varhimo and Klaus Niemel{\"a} and Tapani Vuorinen",
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Sodium sulphite pulping of Scots pine under neutral and mildly alkaline conditions (NS pulping). / Hanhikoski, Saara (Corresponding Author); Warsta, Elina; Varhimo, Antero; Niemelä, Klaus; Vuorinen, Tapani.

In: Holzforschung, Vol. 70, No. 7, 2016, p. 603-609.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Sodium sulphite pulping of Scots pine under neutral and mildly alkaline conditions (NS pulping)

AU - Hanhikoski, Saara

AU - Warsta, Elina

AU - Varhimo, Antero

AU - Niemelä, Klaus

AU - Vuorinen, Tapani

PY - 2016

Y1 - 2016

N2 - Sodium sulphite pulping of Scots pine chips in the initial pH range of 7.5-9 was investigated at 180°C and 165°C (for 120-240 min), using chemical charges between 25 and 50% and anthraquinone (AQ) charges 0-0.2%. As a result, pulps with yields of 52-73% and kappa numbers of 35-106 were produced. Delignification was accelerated by higher Na2SO3 charges and temperatures, and by AQ addition, whereas the effect of initial pH was negligible. The high pulp yields at a given kappa number were attributable to high retention of hemicelluloses, especially that of galactoglucomannan. The relatively low viscosities of pulps were apparently caused by depolymerisation of cellulose by sulphite. The sulphonic acid groups in the pulps correlated well with the residual lignin content, although some sulphonation of polysaccharides may also be possible. The results indicate that pulping of softwood in buffer-free (without Na2CO3 and/or NaOH) sodium sulphite liquor may result in pulps with tailored characteristics.

AB - Sodium sulphite pulping of Scots pine chips in the initial pH range of 7.5-9 was investigated at 180°C and 165°C (for 120-240 min), using chemical charges between 25 and 50% and anthraquinone (AQ) charges 0-0.2%. As a result, pulps with yields of 52-73% and kappa numbers of 35-106 were produced. Delignification was accelerated by higher Na2SO3 charges and temperatures, and by AQ addition, whereas the effect of initial pH was negligible. The high pulp yields at a given kappa number were attributable to high retention of hemicelluloses, especially that of galactoglucomannan. The relatively low viscosities of pulps were apparently caused by depolymerisation of cellulose by sulphite. The sulphonic acid groups in the pulps correlated well with the residual lignin content, although some sulphonation of polysaccharides may also be possible. The results indicate that pulping of softwood in buffer-free (without Na2CO3 and/or NaOH) sodium sulphite liquor may result in pulps with tailored characteristics.

KW - anthraquinone (AQ)

KW - galactoglucomannan (GGM)

KW - high yield pulp

KW - lignin

KW - neutral sulphite pulping (NS)

KW - neutral sulphite semi-chemical pulping (NSSC)

KW - sodium sulphite

KW - softwood

KW - sulphonic acid group

U2 - 10.1515/hf-2015-0099

DO - 10.1515/hf-2015-0099

M3 - Article

VL - 70

SP - 603

EP - 609

JO - Holzforschung

JF - Holzforschung

SN - 0018-3830

IS - 7

ER -