A comparison of kraft, PS, kraft-AQ and kraft-NaBH 4 pulps of Brutia pine

Abstract

The aim of this work was to study the effect of adding PS, AQ and NaBH 4 into kraft pulping with special attention given to NaBH 4. Kraft, kraft-AQ, PS, and kraft-NaBH 4 pulps were produced under the same cooking conditions and the pulps produced were compared in terms of pulp and paper properties. Kraft method was modified by adding 0.1% AQ, 4% PS and 2% and 4% NaBH 4 and the resultant pulps displayed an increase in pulp yield and reduction in both kappa number and screening rejects. On the other hand, there observed an increase in both pulp yield and kappa number when the kraft was modified to PS method. The benefits of NaBH 4 addition into kraft pulping was a significant reduction in kappa number and screening rejects and a significant increase in pulp yield. The most notable outcome of NaBH 4 was 66.6% increase in pulp brightness when 4% NaBH 4 was added into kraft pulping. Of unrefined pulps, unrefined kraft pulp displayed the highest strength of pulp, which is described as tear index at a constant tensile index. Of refined pulps, kraft-AQ showed the highest pulp strength when refined to 6000 and 12,000 revs in PFI mill.