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Titre du document / Document title

Recovery and utilization of fibre from recycled papermill sludge

Auteur(s) / Author(s)

KRIGSTIN S. (1) ; SAIN M. (1) ;

Affiliation(s) du ou des auteurs / Author(s) Affiliation(s)

(1) Centre for Biocomposites and Biomaterials Processing, Faculty of Forestry, University of Toronto, CANADA

Résumé / Abstract

A viable papermaking fibre can be obtained from dried papermill sludge, according to the Canadian research work described in this feature. The sludge, which was obtained from tissue and newsprint mills, was dried in a production scale AGES/KDS Micronizer at one of the mills - an energy efficient system which dewaters the sludge mechanically and leaves it amenable to fibre separation. The papermaking fibre was fractionated from two sources of dried sludge and successfully utilized in handsheets blended with TMP pulp. While average fibre length is not reduced by AGES/KDS drying, many fibres did appear to have been damaged by the recycling and/or KDS process. This damage includes: fibre collapse, twist, kinks, transverse cracks in the cell wall and longitudinal splits. Despite the observed damage, the intrinsic strength of the recovered fibre was found to be acceptable for use as a papermaking fibre. Indeed, the recovered NP/TM fibre has a higher intrinsic strength than the TMP pulp, which can be attributed to the high proportion of strong, chemical fibre in this sludge. However, the tensile indexes of the handsheets were strongly influenced by the recovered fibre content. Tensile strength was reduced by approximately 1% with each percent addition of recovered fibre. The lower tensile strength of the blended handsheets is attributed to the reduction of bond area and interfibre bondability. The surface of the dried fibres was clean of external fibrils which suggests the amount of surface area available for bonding between fibres is minimal. The bond area is also reduced by hornification. The reduction in tensile strength can also be partially explained by the amount of ash present in the handsheets, since i) the ash substitutes for fibre, there is less fibre available to carry the tensile load - ie the ash contributes weight but little load carrying capability. ii) the clay can interfere with the fibre-to-fibre hydrogen bonding, thereby reducing the relative bond area in the paper. The viability of recovering fibre from sludge dried by the AGES/KDS Micronizer depends on the proportion of ash present in the sludge, since ash interfers with hydrogen bonding and has negative effect on strength. Calcium carbonate (CaCO3), which represents a significant portion of the ash, was found to account for: ○ 14% of the Newsprint sludge (NP). ○ 31% of the tissue mill sludge (TM) - the result of the high proportion of coated magazine grades in the furnish. ○ 21% of the combined tissue and newsprint mill sludge (NP/TM).

Revue / Journal Title

Paper technology    ISSN  0958-6024 

Source / Source

2005, vol. 46, no7, pp. 37-46 [10 page(s) (article)] (26 ref.)

Langue / Language

Anglais

Editeur / Publisher

PITA, Bury, ROYAUME-UNI  (1989) (Revue)

Mots-clés anglais / English Keywords

Scanning electron microscopy

;

Calcium carbonate

;

Hydrogen bond

;

Ash

;

Tensile strength

;

Mechanical properties

;

Damaging

;

Crack

;

Thermomechanical pulp

;

Tissue paper

;

Mud

;

Wood fiber

;

Newsprint

;

Manufacturing

;

Experimental study

;

Mots-clés français / French Keywords

Microscopie électronique balayage

;

Calcium carbonate

;

Liaison hydrogène

;

Cendre

;

Résistance traction

;

Propriété mécanique

;

Endommagement

;

Fissure

;

Pâte thermomécanique

;

Papier mousseline

;

Boue

;

Fibre bois

;

Papier journal

;

Fabrication

;

Etude expérimentale

;

Mots-clés espagnols / Spanish Keywords

Microscopía electrónica barrido

;

Calcio carbonato

;

Enlace hidrógeno

;

Ceniza

;

Resistencia tracción

;

Propiedad mecánica

;

Deterioración

;

Fisura

;

Pasta termomecánica

;

Papel seda

;

Lodo

;

Fibra madera

;

Papel periódico

;

Fabricación

;

Estudio experimental

;

Localisation / Location

INIST-CNRS, Cote INIST : 8248, 35400013188223.0040

Nº notice refdoc (ud4) : 17078790



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