Absorbable Organic Halide Reduction Research in Elemental Chlorine-Free Bleaching of Eucalyptus Kraft Pulp

Abstract

ABSTRACT:The parameters of elemental chlorine-free (eCf) bleaching (D 0 E p D 1 ) of eucalyptus kraft pulp were optimized to reduce aox formation. The optimal conditions were pulp concentration 10%, Clo 2 dosage 2.8%, ph 3.5, temperature 60°C, time 60 min at D 0 ; h 2 o 2 dosage 1.25%, alkali dosage 2.0%, temperature 65°C, time 105 min at E p ; Clo 2 dosage 0.2%, ph 4.5, temperature 60°C, time 55 min at D 1 . aox formation was 0.553 kg.tp -1 , each stage was 0.470 kg.tp -1 , 0.060 kg.tp -1 and 0.023 kg.tp -1 , respectively. Compared with un-optimized aox formation decreased by 23.7%.The brightness and viscosity was 84.36% iSo, 834.6 mL.g -1 . in fact, good quality of the pulp was obtained when aox formation has fallen dramatically. These provide a theoretical basis for reducing the produce of aox and realizing the clean bleaching.