Effect of Diluted Acid Pre-Extraction on Soda Pulping of Bagasse

Pre-extraction of hemicelluloses prior to pulping allows co-production of pulp and different hemicellulose-based chemicals in the chemical pulp mills. Due to important impact of hemicelluloses on pulp properties، their pre-extraction would be carried out in controlled conditions to minimize adverse effects on pulp properties. In this study، we focused on the effect of dilute acid pre-extraction on soda pulping and paper properties of bagasse to determine the optimum conditions for hemicelluloses extraction. The pre-extracted with dilute sulfuric acid was performed with 1، 2 and 4% of sulfuric acid concentration (w/v)، liquid-to- solid ratio of 5، at 120، and 140 and 160 °C for 5، 10 and 15 minutes. Then، untreated and treated bagasse at selected condition were used to produce soda pulp with 11، 14 and 17% active alkali and then the selected pulps were bleached in ECF sequence. The pre-extraction results showed that dilute acid pre-extraction by 1% H2SO4، at 120 oC for 60 minute provided the best results regarding to extraction yield and residual holocellulose. However، screen yield، bleaching yield، tensile and burst strengths of obtained pulp from extracted bagasse were significantly lower than that obtained from unextracted bagasse، presumably due to considerable extraction of hemicelluloses.