Determination of Mechanical Fiber Content in Mixed Office Papers Using Image Analysis

A combined deinking/factionation pilot scale study of mixed office paper was carried out using a commercially available agglomeration chemistry and three inch centri-cleaner. One of the objectives of this research was to quantity the change in mechanical fiber content of the process streams. To achieve this objective, an image analysis procedure using a personal computer and flat bed scanner was developed. With this procedure specially prepared filter pads are analyzed for both ink and mechanical fiber area coverage. This allows for the determination of relative changes in mechanical fiber content independent of changes in ink content. This method is considered quantitative within the limits of the applied procedure. The study demonstrated the ability to selectively fractionate the mechanical fiber content of mixed office paper with the centri-cleaner setup. Additionally, a distinct difference in the fractionation behavior of recycled and never dried mechanical fibers was observed.