Best Practices in Fiber Fractionation Among United States Recycled O.C.C. Mills, 1997 Recycling Symposium Proceedings

Fractionation of Old Corrugated containers (OCC) pulp, using pressure screens, into long and short fiber streams for production of recycled two and three-ply linerboard is investigated in five U.S. mills. These mills practice fractionation for one or more of the following benefits:

* increased production in the system
* Reduce virgin fiber requirements
* Greater quality control flexibility in the end products
* Reduced energy requirements in the system
* Reduced equipment capital expenses
* Greater strength development capabilities for individual linerboard top, middle and/or base plies
* linerboard surface property enhancement
* Increased cleaning efficiencies throughout the system

Data collected from these five confidential nulls shows that these different practices of fractionation have been successful in segregating long fibers (LF) and short fibers (SF) into two pulp streams for separate processing. Evidence of 10-30% improved long fiber concentration in the LF stream exists. Up to 87% debris segregation efficiency is achieved in these fractionation practices. Optical fiber length analysis show that there is a 16-21% increase in the length weighted average (LWA) of the LF fractions when compared to the SF fractions. Noticeable energy and equipment capital cost savings become obvious when the system designs for these mills are reviewed.