Impact of Disperser Bleaching with Peroxide on the Efficiency of Flotation, 1995 Pulping Conference Proceedings

Michel Dubreuil

Chemprox Chemical Inc.

Roger Gaudreault

Cascades Inc.

Hervé Suty

Elf Atochem S. A. (CAL)

Disperser bleaching with H2 O2 before flotation is shown to be efficient. The addition of alkaline peroxide bleach liquor into an industrial disperser was followed by a bleaching experiment in the laboratory using a thermostatically controlled water bath to simulate a bleach tower. Both unbleached and H2 O2 bleached pulps were then deinked in the laboratory, under identical conditions; using a Lamort Flotation Cell. Our investigation revealed that H2 O2 Chemistry is reducing the yield loss of flotation as well as providing an additional brightness gain across the flotation cell. This additional gain in brightness is obtained on a higher initial brightness in the feed of the flotation cell. As confirmed by Image Analysis Data, the H2 O2 Chemistry is also improving the ink removal efficiency of flotation. Interestingly, this improvement in efficiency is achieved on a lower inked area per area measured in the feed of the flotation cell using H2 O2 . The paper presents material balances for the TSS, the FSS, as well as testing results for: Consistency, LWA, Freeness, Ink Concentration, Brightness, Color, and Fluorescence Index.