New mechanical treatment for chemical pulp

Abstract

Abstract

This study presents a new method to modify chemical pulp mechanically using an ultra-fine friction grinder, which works in a different way compared with conventional refiners. It consists of two grinding stones: a lower rotating one and an upper stationary one. The pulp passing through the gap between the stone plates is subjected to compressive and shear forces.

The results showed that the gap clearance of the grinder plays an important role in controlling the fibrillation of fibres and the specific energy. External fibrillation became a dominant effect at a larger gap, whereas internal fibrillation developed faster at a smaller gap. Fibres were modified mostly into fibrils at a much smaller gap. Scott bond strength of pulps treated in the grinder was better than that of Valley-beaten pulps. Pulp properties can be varied by adjusting the pulp consistency, rotating speed, grit size, the dullness of the plate surface, and the number of pulp recirculations.