Dispersed Resin in Bleached Kraft Pulp Mills

Abstract

Several properties of the dispersed resin in bleached kraft pulp mills have been investigated. Average concentrations of resin particles in filtrates of pulps from various points along the process stream are reported. For each sampling location, the change in particle concentration with time of pulp sample storage at 5°C has been determined. In the future, this will enable rough estimation of original concentrations when samples must be measured a few days after collection. Size distributions of resin particles were the same at all sampling points, from which it follows that, in practice, the relationship between concentration and deposition rate is relatively unaffected by size distribution. Dispersed resin particles were negatively charged throughout the mills. The low charge observed in C-stage pulps was insufficient to confer stability, which further supports the hypothesis that the dispersed resin is heterocoagulated with the fibers in this acidic stage.