Comparison of Bleaching Sequence Configurations of Aspen CTMP with Respect to Brightness Gain and Stability, 1999 Pulping Conference Proceedings
George X. Pan
Alberta Research Council
The bleaching performance of aspen CTMP is investigated by using peroxide alone and sequentially with other bleaching agents. In comparison with peroxide, peracetic acid and ozone do not show meaningful advantage in terms of brightness development. Their sequential combination with peroxide does not show any synergy. On the other hand, addition of a reductive bleaching stage, FAS or sodium hydrosulfite, after peroxide bleaching stage(s) offers additional brightness gain and, however, has little effect on brightness stability. Comparison of various multi-stage bleaching sequences indicates that for a given total charge of bleach chemicals the number of peroxide bleaching stages only marginally affects the final brightness. Nevertheless, multi-stage bleaching sequences save peroxide to reach the same brightness as compared to single-stage.