High Yield Pulping of Jack Pine, 1997 Pulping Conference Proceedings

For many decades, the utilization of jack pine (Pinus banksiana Lamb.) in the pulp and paper industry has attracted considerable interest but without any major breakthrough. However, in the past few years the emergence of new technologies has provided hope for its potential use. The present paper reports the work performed so far on jack pine to produce a high yield pulp using two different technologies : alkaline hydrogen peroxide interstage treatment and bio-treatment. In this study, the two treatments were combined to verify the possibility of synergistic effect. The experimental fungus under the conditions used in this investigation does not appear to be aggressive enough to grow on jack pine chips, which are known to be naturally resistant to fungal attack. The interstage alkaline peroxide treatment fails to reduce the energy consumption and it is therefore not the best choice to improve the mechanical properties. The addition of 3.5% hydrogen peroxide in a two-stage impregnation at a temperature of 115°C for 5-6 minutes reduces the specific refining energy consumption below that required by spruce TMP, and increases the physical properties at values comparable to spruce AP-TMP. Unfortunately, the resulting brightness is low when compared to the initial value observed in pine TMP. The addition of hydrogen peroxide into the eye of the refiner with dilution water gives also the same reduction of the specific refining energy but slightly lower mechanical properties. However, the initial brightness of the wood was maintained. The addition of 3% hydrogen peroxide in a single-stage refining leads to a better brightness with good mechanical properties but the specific refining energy is higher than for the two-stage process. The advantage of this process is that it does not require special equipment since the bleaching liquor is added directly in the standard TMP process. The latter two processes show a significant reduction of extractives’ content at a level acceptable for the papermaking equipment. These conclusions indicate some new possibilities for the utilization of jack pine chips in high yield pulping processes.