Abstract
Softwood (Picea abies) sawdust was hotwater- extracted
with two multi-phase processes (160- 180°C, 100-280 min,
and liquor-to-wood ratio 5 l/kg) corresponding to
P-factors of ~780 (yield 80.0%) and ~4580 (yield 72.4%).
The pre-treated materials were then pulped with the
soda-AQ cooking (170°C, NaOH charge 20%, AQ charge 0.1%,
30-150 min, and liquor-to-wood ratio 5 l/kg), resulting
in a yield range of 36.1-61.4% (for reference cooks
without pre-extraction 47.9-60.0%). It was observed that
the pre-extraction under moderate conditions enhanced the
dissolution especially of largemolar- mass lignin during
cooking, and the total amount of the dissolved lignin was
also higher than that removed from the material
pre-extracted under harsh conditions. Additionally, in
the former case the pulps with rather good properties
(high yield and low amount of pulp rejects) were
obtained, whereas in the latter case, a pronounced
degradation of pulp carbohydrates to aliphatic acids was
observed resulting in lower pulp properties.
Original language | English |
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Pages (from-to) | 41-48 |
Journal | Nordic Pulp and Paper Research Journal |
Volume | 31 |
Issue number | 1 |
DOIs | |
Publication status | Published - 2016 |
MoE publication type | A1 Journal article-refereed |
Keywords
- Aliphatic acids
- Carbohydrates
- Extractives
- Hemicelluloses
- Hot-water pre-treatment
- Lignin
- Molar-mass distribution
- Norway spruce