High-yield Alkaline Peroxide Chemimechanical Pulping of northeastern hardwoods

The Alkaline Peroxide Mechanical Pulping (APMP) process has been shown to produce high quality pulp commercially from aspen wood. Difficulties have been reported in applying the process to the typical hardwoods in the Northeastern United States due to their higher density and darker color. The objective of this study was to produce strong, bright APMP pulp from northeastern hardwoods. In this study, hardwood chips (Betula paperifyra, Acer rubrum, and Populus tremuloides) were pulped using a variation on the APMP process. Control pulps (TMP) were made with no chemicals. The process was repeated using mixed hardwood chips from a local pulp mill. Pulp yield for the process averaged about 90%. The poplar and birch chips produced the strongest APMP pulps, while the mixed and maple pulps were weaker. Only the poplar chips produced a TMP with reasonable strength. Brightness of the poplar and birch pulps averaged 81% ISO, while the maple pulps averaged 79% ISO. The mixed hardwood chips produced a pulp that was stronger than the maple pulp but weaker than the birch and poplar pulps.' The maximum brightness achieved with the mill chips was 73% ISO.