Alkaline Pulping and Bleaching of Acacia auriculiformis Grown in Bangladesh

Authors : M Sarwar JAHAN, Rowshan SABINA, Arjumand RUBAIYAT

Pages : 339-347

View : 19 | Download : 13

Publication Date : 2008-07-01

Article Type : Research Paper

Abstract :The physical, chemical, and morphological characteristics of Acacia auriculiformis were evaluated in terms of its suitability for papermaking. The fiber length insert ignore into journalissuearticles values(1.1 mm); of A. auriculiformis in this study was within the range of tropical hardwoods. The lignin content in A. auriculiformis was 19.4% and a-cellulose 44.1%, which was within the range of other acacias, but that of extractives was higher. Soda, soda-AQ, and kraft processes were studied in pulping. Screened pulp yield was increased with increasing active alkali. Acceptable pulp yield insert ignore into journalissuearticles values(43%-44%); and kappa number insert ignore into journalissuearticles values(22-24); were obtained at 20% alkali and 2.5 h of cooking in soda, 16% alkali and 2.5 h of cooking in soda-AQ, and 18% alkali in 2 h of cooking in kraft process. Soda-AQ pulp showed better strength properties than soda and kraft pulp. Soda, soda-AQ, and kraft pulps were bleached in DEpD and DEpDEpD insert ignore into journalissuearticles values(where D denotes Chlorine dioxide, E denotes peroxide reinforced alkaline extraction); bleaching in different kappa factors. In DEpD bleaching, kraft pulp showed better bleachability as compared to soda and soda-AQ pulp. However, in case of DEpDEpD bleaching, all pulps exhibited almost the same brightness. At the same kappa factor, final brightness of pulp increased from 72%-75% to 85%-86% with splitting DEpD and DEpDEpD sequences, respectively.
Keywords : Acacia auriculiformis, pulp yield, kappa number, strength properties, bleachability, viscosity