THE RELATION OF WOOD TYPE TO PULP QUALITY FROM 3 RADIATA PINE TMP PLANTS AT AUSTRALIAN NEWSPRINT MILLS

Australian Newsprint Mills, Boyer mill has considered increasing the capacity oi its TM pulping piani to produce consistent TMP-rich newsprint. Pulp strength from various sources oi radiata pine with various refiner types, is an issue which has been investigated with refiner types used in ANM 's mills. Experiments have been undertaken using the same (young) wood type, to probe the differences between Boyer and Albury mill chip refiners. Wood c. 15 year old gives unacceptably weak pulp when pulped through a single stage open discharge double disc refiner in contrast very acceptable pulp strength is given by single disc type refiners from this type of wood. Pulp strength from the double disc refiners is very dependent on tracheid length/coarseness in the wood. Older wood containing long fibres, when put through this refiner; gives pulp superior to that obtained from young wood pulped in the two stage single disc refiner A pressurized single stage double disc gave pulp no better in strength compared to a similar type with open-discharge.