HIGH-YIELD PULPING OF JACK PINE

This paper reports on efforts to produce high yield pulps from jack pi ne (Pinus banksiana Lamb.). Two technologies were initially investigat ed: biotreatment and an alkaline hydrogen peroxide interstage treatmen t. Biotreatment was ineffective because the experimental fungus would not grow on jack pine chips. The interstage alkaline peroxide treatmen t failed to reduce energy consumption (specific refining energy). Neve rtheless, this investigation did identify peroxide treatments that red uced energy consumption below the level required by spruce thermomecha nical pulp. Addition of 3.5% hydrogen peroxide in a two-stage impregna tion (115 degrees C, 5 min) reduced energy consumption while improving pulp mechanical properties and reducing pulp brightness. Addition of 3.5% hydrogen peroxide into the eye of the refiner with dilution water reduced energy consumption while maintaining pulp brightness and slig htly decreasing pulp strength. Addition of 3% hydrogen peroxide during single-stage refining produced a pulp with higher brightness and good mechanical properties, but the specific refining energy was higher th an for a two-stage process. This is an attractive alternative because it does not require special equipment. These results suggest that jack pine chips can be used to produce high-yield pulps.