Nordic Pulp & Paper Research Journal Vol 31 no (3) 2016
Some process aspects on single-stage bisulfitepulping
Raghu Deshpande, Lars Sundvall, Hans Grundberg and Ulf Germgård
KEYWORDS: Activation energy, Bisulfitepulping,
Cellulose, Extractives, Glucomannan, Lignin, Pine,
Spruce, Thiosulfate, Xylan
SUMMARY: Sulfite pulping of pine is well-known to
be a risky process because problematic lignin conden-
sation reactions can occur resulting in poor pulp quality.
However, sulfite pulping of pine is interesting of
Water sorption and surface composition of untreated or
oxygen plasma-treated chemical pulps
Gilbert Carlsson and Goran Strom, Institute for Surface Chemistry, Stockholm, Sweden
Goran Annergren, SCA Research AB, Sundsvall, Sweden
Keywords: Kraft pulps, Bisulfitepulps, Wettability, Water
sorption, Plasma, Oxygen, Surface composition, ESCA.
SUMMARY: Three kraft pulps and one bisulphite pulp have
been studied. The surface chemical composition was deter-
mined by means of ESCA, and water sorption was studied
using a dynamic contact angle tester. The surface
Unconventional strength additives
Makhlouf Laleg and Zvan I. Pikulik, Pulp and Paper Research Institute of Canada, Pointe Claire, Quebec, Canada
Keywords: Additives. Wet webs, Wet strength, Dry strength,
Cationic compounds, Aldehyde groups, Starch. Zirconium
compounds. Bisulfitepulps. Kraft pulps. Thermomechanical
SUMMARY: Unconventional additives for increasing the
strength of never-dried wet webs, dry paper and rewetted paper
were investigated. It was found that handsheets made from
bisulphite pulps or kraft pulps can be reinforced by cationic
hemicellulose sugar residues ( Table 2 ). As the LS under study were extracted from softwood, most of the hemicellulose residues are in the form of galactoglucomannan. The major part of the residual sugars is recovered in the low MW fraction UF<1. This means that they are mostly in the form of monomers or oligomers, and not attached to the lignin, which allows them to pass across the membranes. This finding seems to be plausible as the hemicelluloses are easily hydrolyzed to monomers and oligomers under the acidic conditions of bisulfitepulping, whereas the ether and ester
the results obtained so far, it can be concluded that
wet storage of beech wood logs efficiently prevents the
formation of chromophore compounds which negatively
affect acid bisulfitepulping.
1)Dedicated to Prof. Horst Nimz at his retirement as Editor-in-
Chief of Holzforschung (1993–2003)
Keywords: bisulfite process; dissolving pulp; Fagus syl-
vatica L.; log storage; UV microspectrophotometry.
For wood dissolving pulp production, only acid bisulfite
cooking and the prehydrolysis kraft process are of major
practical importance. Unlike paper grade
Spent sulfite liquor derived from magnesium bisulfite pulping of beech was electrolyzed in a pilot-plantelectrolysis cell. During the electrochemical treatment (125 mA cm−2; 60°C; 180 min), desalination of the anolyte took place and the magnesium concentration was reduced to approximately 60%. In addition, the pH decreased from 5 to 1. Three differently treated liquors (SSL pH 5; SSLe pH 2.5; SSLe pH 1) were chosen for further analysis. The average molar mass of the fractions was determined by size exclusion chromatography. Extended electrolysis time increased the molar mass of the lignosulfonates (Mw: SSL pH 5, 5700 g mol−1; SSLe pH 2.5, 6500 g mol−1; SSLe pH 1, 7400 g mol−1). The content of phenolic hydroxyl and sulfonic acid groups did not undergo significant changes. Nevertheless, lignosulfonates obtained after electrolysis showed higher charge densities than the unmodified product (SSL pH 5, 1590 μeq g−1; SSLe pH 2.5, 1760 μeq g−1; SSLe pH 1, 1920 μeq g−1). Separation of the liquors into five fractions was performed using four ultrafiltration membranes (100, 50, 10 and 1 kDa). This allowed detailed structural analysis of high- and low-molar-mass lignosulfonate fractions in terms of the modifications induced by electrolysis.
assumed that the degree of polymerisation äs
well äs the molecular mass distribution of the native celluloses show
about the same values independent of the age and kind of tree.
\ \ Treiber/1009
A. Greune and D. Fengel: Elektronenmikroskopische Unter-
suchungen zum Magnesiumbisulfit-Aufschluß von Kiefernholz.
1. Mitt. Tränkverhalten von Kiefernholz verschiedener Feuch-
tigkeitsgehalte. (Electron microscopic investigations on mag-
nesium bisulfitepulping of pine wood. Part I. Impregnation be-
haviour of pine wood with various moisture contents.) Das
Papier 42 (1988): 4
corresponding soda pulps.
A.F.A. Wallis and R.H. Wearae: Preparation of chemical
cellulose from radiata pine bisulfitepulps without using
chlorine-containing reagents. Appita45 (1992): 4, 239-242.
Cellulose suitable for a range of applications including derivatisa-
tion (dissolving pulps) may be prepared by cold alkali extraction
(4 -> 11% NaOH; 20 °C) of radiata pine tjisulfite pulp which had
been bleached at 20-25% stock concentration with hydrogen
peroxide (2-4%). Sequential treatment of the pulp with peroxide
and alkali without interstage washing also gave
T. J. Smith et al: Chlorohydroxypyrone in Filtrates of Chlorine Bleached Pulps 423
48 (1994) 423-428
An Ubiquitous Chlorohydroxypyrone in Filtrates
from Chlorine Prebleaching of Alkaline Pulps
By Terrence J. Smith, ROSS H. Wearne and Adrian F. A.Wallis
Division of Forest Products, CSIRO, Clayton, Victoria, Australia
P in us radiata
An abundant chlorinated