Chemimechanical pulping of New Zealand grown Eucalyptus fastigata

Plantation grown Eucalyptus fastigata was evaluated for its chemimechanical pulping potential using the cold soda and alkaline peroxide mechanical pulping (APMP) processes and a range of process conditions. Cold soda pressurised high consistency two-stage refining produced pulps with good strength properties and moderate optical properties, while cold soda atmospheric low consistency single stage refining, or a combination of atmospheric high consistency primary/low consistency second stage refining, was limited by the amount of energy that could be applied in the low consistency refining stage. Pulps of;high freeness were produced with single stage refining and fibre cutting occurred with plate gap reduction during low consistency second stage refining. The APMP process produced pulps with a lower energy demand to a given freeness than the cold soda process. The APMP pulps had similar sheet density, strength and light scattering properties to the cold soda pulps when compared at the same freeness.