The pulping characteristics of bigleaf maple (Acer macrophyllum Pursh) / by Tommy Dale Farr

Graduation date: 1970Bigleaf maple chips were pulped by the kraft, Magnetite, neutral sulfite semichemical, and refiner groundwood processes. Pulp from each process was refined in a Valley Beater and the handsheet properties of the refined pulp were compared to similar pulps made from other wood species. For the kraft process a different concentration of active alkali was used in five separate cooks while the other cooking parameters were kept constant As the level of active alkali was lowered the unscreened yield increased from 47 2% to 55.6%. The average brightness of the kraft pulp was 41% (% reflectance at 457 nm as measured by an Elrepho Colorimeter) The pulp strengths were generally improved with higher yields. Samples of the kraft pulp were bleached using a five stage bleaching sequence and the handsheet properties of the bleached pulp were evaluated. The Magnetite cooking schedule gave an unscreened yield in the 50-55% range and a 62.2% brightness Samples of the Magnetite pulp were bleached using a three stage bleaching sequence and the handsheet properties of the bleached pulp were evaluated There were four neutral sulfite semichemical cooks made with yields ranging from a high of 90 5% to a low of 76.1%. The corrugating medium test remained nearly constant as the yield varied, but the other strength values increased with decreasing yields The refiner groundwood was manufactured in three passes through a Bauer double disc refiner. The resultant pulp was beaten to 100 Canadian standard freeness and bleached to 58 1% brightness using 1% (w/w) zinc hydrosulfrte. In general, bigleaf maple can be converted into pulp possessing hands heet properties similar to pulp made from other hardwood species. The kraft and Magnetite pulps were bleached using standard bleaching techniques and the pulp lost very little strength in the process. The refiner groundwood pulp was disappointing because it lacked strength The kraft, Magnetite, and NSSC pulps were found to have strength properties competitive with the hardwood pulps presently being manufactured