Extractive Removal and Selectivity Improvement by Various Pretreatment Methods Prior to Oxygen Delignification for Acacia mangium and Mixed Hardwood Kraft Pulps, 2007 Engineering, Pulping & Environmental Conference

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The objective of this study was to evaluate different pretreatment methods prior to oxygen delignification on the extractive removal and selectivity improvement. Four different pretreatment methods were examined: applying ultrasonic energy, hot water soaking, soda addition with preheating, and applying mechanical shear. Acacia mangium and mixed hardwood (MHW) kraft pulps were used in this study. MHW kraft pulp did not show a significant extractive removal in all pretreatment methods during oxygen delignification. This was probably due to a low extractive content of pre-O2 MHW kraft pulp to begin with. A dramatic extractive removal occurred on the Acacia mangium pulp that was pretreated. The ultrasonic pretreatment followed by filtering induced extractive removal. Mechanical pretreatment prior to oxygen delignification promoted a better selectivity for both Acacia mangium and MHW pulps. Ultrasonic and mechanical pretreatments did not create fines formation.