Disc separation: wetting angle differences

The difficulty in removing synthetic adhesive contaminants from wastepaper pulps is caused mainly by the nonwettable contaminants having about the same size and density as wetted pulp fibers. Present screening and cleaning operations are not effective in removing them. To demonstrate that disc separation can separate fibers based on their wetting angle differences, an experiment was performed by disc separating a slurry of two different fibers. These fibers had different wetting angles, nearly identical densities, and diameters which opposed the separation based on wetting angles. One was a commercial nylon fiber, and the other was a hot- melt adhesive (HMA) fiber produced in the laboratory. The results encourage development of disc separation for removing such contaminants from