Utilization of sodium borohydride (NaBH4) in kraft pulping process.

Aim of this study is to investigate the effect of adding sodium borohydride (NaBH4) in kraft pulping. First of all, six kraft cooks were carried out for varying active alkali and sulfidity. Then, kraft methods for K1 and K6 cooks were modified by adding 1, 2 and 3 % NaBH4. The results indicated that modifying kraft method (K1) by adding 3% NaBH4 (KB13) resulted in 9.97% (relative percentage) yield increase and 10.1% (relative percentage) kappa reduction. Although the mechanical properties of NaBH4 modified pulps were lower compared to the kraft pulps, NaBH4 modified pulps were much brighter.