Fiber- and fine fractions-derived effects on pulp quality as a result of mechanical pulp refining consistency

• Published in: Wood science and technology Vol. 48; no. 4; pp. 737 - 753
• Main Authors: Hafrén, Jonas, Fernando, Dinesh, Gorski, Dmitri, Daniel, Geoffrey, Salomons, Florian A
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 2014; Springer Berlin Heidelberg; Springer Nature B.V
• Subjects: Biomedical and Life Sciences; Ceramics; Composites; Consistency; energy; Energy demand; Fibrils; Fluorescence; Fluorescence microscopy; Fractionation; Glass; Lamellae; Life Sciences; Light scattering; Machines; Manufacturing; mechanical pulp; Medicin och hälsovetenskap; Microscopy; Morphology; Natural Materials; Newsprint; Optical properties; Original; Paper, Pulp and Fiber Technology; Pappers-, massa- och fiberteknik; Process parameters; Processes; Pulp; Pulping; Qualitative analysis; Refining; Scanning electron microscopy; Scattering coefficient; tensile strength; Wood chips; Wood Science & Technology; ATMP; Relative Bond Area; Compound Middle Lamella; Lamella Sheet; Tensile Index
• DOI: 10.1007/s00226-014-0636-1
• EISSN: 1432-5225
• ISSN: 0043-7719; 1432-5225

High-yield pulping of wood chips using low-consistency (LC) refining in combination with primary-stage high-consistency (HC) refining has previously been shown to produce paper with quality parameters (tensile strength and light-scattering coefficient) commonly targeted for newsprint with significantly less refining energy input than using only HC refining. However, questions remain on the differences in the refining action between the two refiner types and for high-yield pulping, the refiner energy demand is a crucial process parameter. Therefore, fines- and fiber-fraction development in HC and LC refining has been studied in detail using Bauer-McNett fractionation, and the respective tensile strengths of the different fractions have been compared. Quantitative and qualitative (morphological) characteristics of the isolated fine fractions have also been analyzed in detail using a newly developed automated fluorescence microscopy method and scanning electron microscopy. The results suggest the difference in LC/HC pulp properties (strength and optical) is partly derived from deviating fiber and fines morphologies and mass balances. The quality of the fines generated during HC and LC refining also differs. LC-refined pulps contain thinner fibrillar fines (thread-like) and HC-refined pulps broader fibrils such as lamellae-type fines. Flake-like fines from the outer fiber wall decreased in relative amount with energy input.