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Alkaline extraction of ozonated kraft pulps Jonas Sundin and Nils Hartler, Royal Institute of Technology, Department of Pulp and Paper Chemistry and Technology, Stockholm, Sweden for the alkaline stage are changed. A pulp treated with Keywords: Alkali extraction, Bleaching, Hydrogen peroxide, ozone does not have the same properties as that treated Kraft pulps, Oxygen, Ozone. with chlorine/chlorine dioxide. The cellulose is more oxidized and the lignin has another structure. An im- SUMMARY: An industrially cooked modified softwood portant change is in the

TCF bleaching of softwood kraft pulp Part 5. Investigation of EDTA-metal complexes in chelation filtrates Harald Brelid and Tommy Friberg. Department of Forest Products and Chemical Engineering, Chalmers University of Technology Keywords: Kraft pulps, Bleaching, Hydrogen peroxide, EDTA, conditions (pH 5-7) has been shown to have very positive Metal complexes, Liquid chromatography, Manganese, Iron, effects on subsequent hydrogen peroxide bleaching (Basta Copper. et al. 1991). After a chelation stage, pulp can be bleached SUMMARY: EDTA-metal complexes in

TCF bleaching of softwood kraft pulp Part 1. Ion exchange of softwood kraft pulp with calcium and magnesium prior to hydrogen peroxide bleaching Harald Brelid, Tornrny Friberg and Rune Sirnonson, Department of Forest Products and Chemical Engineering, Chalmers University of Technology, Goteborg, Sweden Keywords: Kraft pulps, Bleaching, Hydrogen peroxide, Ion exchange, EDTA, Magnesium, Calcium, Manganese, Acid treatment, Washing, Lactones. SUMMARY: The effect of pretreatment with calcium and magnesium acetate of oxygen delignified softwood kraft pulp

TCF bleaching of softwood kraft pulp Part 2. Reducing the need for chelating agent in hydrogen peroxide bleaching of softwood kraft pulp Harzrld Brclid, Ton~nly F~.ihei;~ and Rzrnc Sinlor~son, Department of Forest Products and Chemical Engineering, Chalmers University of Technology, Gothenburg, Sweden. K~?.w,or-ds: Kraft pulps, Bleaching, Hydrogen peroxide, Pretreatment, Ion exchange, EDTA, Magnesium. Calcium, Manganese. SUMMARY: Oxygen delignified softwood kraft pulp was sub- jected to different pretreatments, including ion exchange with calcium and

Bleaching of kraft pulp without chlorination Per Larsson and Olof Samuelson, Chalmers University of Technology, Gothenburg, Sweden Keywords: Kraft pulps, Bleaching, Nitrogen dioxide, Oxy- gen, Ozone, Chlorine dioxide, Chlorine, Pretreatment. SUMMARY: Commercial kraft pulp from Pinus sylvestris impregnated with 222 kg black liquor per 1000 kg pulp was bleached to a brightness of 90% IS0 without chlorination. The alkaline pulp was treated with 2% NO, at 26% consistency, diluted to 8% consistency with acid nitrate solution and ripened at 90°C for 120 min

Kraft pulp of high brightness without chlorination Per Larsson and Olof Sarnuelson, Chalmers University of Technology, Gothenburg, Sweden - Keywords: Kraft pulps, Bleaching, Nitrogen dioxide, Nitric acid, Oxygen, Magnesium, Chlorine dioxide, Chlorine, Hydrogen peroxide, Pretreatment. SUMMARY: Commercial kraft pulps from Pinus sylvestris containing black liquor to simulate carry-over in a closed recovery system were bleached to brightness 90-91 % IS0 by pretreatment with nitrogen dioxide, oxygen bleaching and final bleaching with chlorine dioxide in two

TCF bleaching of softwood kraft pulp Part 4. Removal of manganese from wood shavings prior to cooking Harald Brelid, Tonznzy Friberg, and Rune Sirnonson. Department of Forest Products and Chemical Engineering, Chalmers University of Technology, Sweden. Keyu,ods: Spruce, Kraft pulps, Oxygen delignification, Bleaching, Hydrogen peroxide, Ion exchange, EDTA, Acid pretreatment, Magnesium, Calcium, Manganese, Iron. SUMMARY The removal of transition metals, especially mang- anese, from spruce wood shavings prior to kraft cooking has been investigated. The

The optical properties of bleached kraft pulps Steven R. Middleton and Anthony M. Scallan, Pulp and Paper Research Institute of Canada, Pointe Claire, Canada Keywords: Opacity, Tensile strength, Bleached pulps, Fil- lers, Visual efficiency, Fiber dimensions, Optical proper- ties, Kraft pulps, Kubelka Munk equation, Titanium diox- ide, Reflectance. SUMMARY: The optical properties of paper prepared from fully-bleached kraft pulps, at any given basis weight, are controlled by their light-scattering coefficients. This coefficient is related to the

Holzforschung, Vol. 63, pp. 402–407, 2009 • Copyright by Walter de Gruyter • Berlin • New York. DOI 10.1515/HF.2009.072 Article in press - uncorrected proof The relationship found between fibre length and viscosity of three different commercial kraft pulps Luc Lapierre*, Jean Bouchard and Richard Berry FPInnovations – Paprican, Pointe-Claire, Québec, Canada *Corresponding author. FPInnovations – Paprican, 570 Boul. St-Jean, Pointe-Claire, Québec, Canada H9R 3J9 E-mail: luc.lapierre@fpinnovations.ca Abstract In this report, two softwood kraft pulps, one

References Ahmed, A., Myers, G.C., AbuBakr, S. (2000) Packaging grade kraft pulp from small-diameter softwood. In: Proceedings of the TAPPI Pulping/Process and Product Quality Conference, 2000. Einspahr , D.W., McDonough, T.J., Joachimides, T. ( 1983 ) Kraft pulping characteristics of European, Japanese, and European×Japanese larch hybrids. Tappi J. 66 : 72 . Hatton , J.V. ( 1993 ) Kraft pulping of second-growth jack pine. Tappi J. 76 : 105 . Hatton , J.V. ( 2001 ) Natural variability and the second crop. Tappi J. 84 : 71 . Hatton, J.V., Hunt, K. (1990