Crofton Kraft Mill converted one of its two bleach plants to utilize a two stage oxygen bleaching sequence in order to reduce conversion costs and increase environmental performance without impacting pulp quality. Oxygen bleaching employs pressurized vessels after the first chlorine dioxide (D_0) stage in order to activate the lignin allowing aggressive oxidation by the oxygen. Oxygen bleaching allows a high percent delignification with no loss in tear and tensile strength and has enabled a reduction in total mill AOX and pulp TOX. This paper updates the findings previously reported by Gerry Ferweda, Jim Pickell and Randy Wunderlich at PacWest, Jasper in 2000.
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