Potential Sulfur-Free Pulping Methods, 2002 Fall Technical Conference

Lodgepole pine chips were pulped to Kappa numbers of about 70 using soda–AQ, soda–ODiMAQ, and kraft methods. At a catalyst level of 0.20% (oven-dry wood basis), cooking times for the soda cooks were significantly shorter than that for the kraft cook. The ODiMAQ catalyzed cooking time was much shorter than that of the AQ cook. It might be possible to replace the kraft process with a soda–ODiMAQ process for production of linerboard grade pulps. Delignification of the high Kappa soda–ODiMAQ pulp with oxygen and also with a polyoxometalate (POM) to Kappa numbers of about 30 resulted in higher yields of slightly weaker pulps than did pulping to Kappa 30 with the kraft process. Soda–ODiMAQ followed by oxygen sequence gave pulps much lower in viscosity than did soda–ODiMAQ followed by POM. If bleaching of oxygen-delignified pulp yields strong pulp, soda– ODiMAQ followed by oxygen delignification might be used to replace kraft pulping for the production of bleachable grade pulps. If the pulp is weak, soda–ODiMAQ followed by POM delignification might be used to replace kraft pulping.