The effect of polysulphide pre-treatment and cooking parameters on the chemical properties and TCF bleachability of alkaline pulps

摘要

The effect of pre-treating softwood chips with polysulphide on the chemical properties of the resulting pulp has been investigated. During subsequent pulping after such pre-treat-ment, high alkali content is maintained in the cooking liquor and, consequently, an unbleached pulp with a decreased amount of hexenuronic acid is obtained. As compared to other kraft pulps in this study, a polysulphide pre-treatment gives high cooking yield, a high viscosity and brightness for the unbleached pulp and a pulp of good bleachability.