The influence of consistency and fibre length on the yield stress of OCC pulp fibre suspensions

Abstract

The effect of fibre length on the yield stress of recycled old corrugated containers (OCC) pulp fibre suspensions was investigated. Two types of OCC pulps were divided into four fractions based on the fibre length with a Bauer-McNett classifier. The yield stress of each fraction was measured using the shear stress ramp method at pulp consistency ranging from 0.5% to 2.5% (w/v). The results showed that both pulp consistency and fibre length had significant effects on the yield stress of OCC pulp suspensions, and the yield stress was greater with increasing fibre length and pulp consistency. Moreover, the effect of consistency in OCC pulp suspension with long fibres on the yield stress was stronger than in the slurry with short fibres.