Errect of High Intensity Treatment on Mechanical Properties of Low Consistency Pulp, 2009 TAPPI Engineering, Pulping, Environmental Conference

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LC-refining is one of the most important processes in papermaking, in which fiber and paper properties can be improved. Traditionally refining is done by using conical or disc low consistency refiners, in which refining occurs in the contacts between fibres and refiner bars as well as between fibres alone. During refining bonding properties of fibres are improved caused by e.g. increased flexibility and fibrillation. Unfortunately, at the same time fibres are more or less cut.

This paper presents the effect of high intensity treatment on fibre development at low consistency. Bleached kraft pulp and thermomechanical pulp were treated in laboratory scale by using high intensity dispergator. In this apparatus the mechanisms of refining differ from traditionally used LC-refiners because fibres are mostly affected by cavitation forces. The effects of fiber-dispergator segment contacts are not that significant, because a gap between the rotor and stator is relatively wide. Pulps were fed to the device at the consistency of 1.0% and refined different times using different power levels. The curved fibres were straightened up as well as fibres were fibrillated while fibre length remained unchanged. Cutting of fibres did not occur in the device. Because of the refining mechanism, the high intensity dispergator could be an interesting novel method for LC- refining.