Active alkali charge effect on kraft pulping process of acacia mangium and eucalyptus pellita

Acacia Mangium and Eucalyptus Pellita had been used as raw material of pulp in Indonesia. In this research 5-year old of the wood were pulped under different active alkali charge varied at 16, 17, 18, 19 and 20% and its effect on pulp yield, pulp viscosity and kappa number was investigated. The cooking was done in a rotating digester Haato 6 chambers and 300 gram of dry mass chips were used, with sulfidity 25%, H-factor 800, temperature 165C and ratio between chips and liquid was 1: 3,5. The pulp screened yield indicates that decreased from 53,7 to 52,25% for acacia mangium and 53,0 to 50,6% for eucalyptus pellita when active alkali charge increased. Kappa number decreased from 19,0 to 16,8 for acacia mangium and 16,69 to 13,4 for eucalyptus pellita when active alkali charge increased. The viscosity decreased from 818 to 378 ml/g for acacia mangium and 697 to 426,8 ml/g for eucalyptus pellita when active alkali charge increased.