RECOVERING PLASTICS FOR RECYCLING BY MINERAL PROCESSING TECHNIQUES

Patents and other literature on recycling post-consumer plastics from various sources (e.g., municipal solid waste) indicate that unit opera tions common to minerals processing have been seriously considered at various times. A review of the available literature and statistics on recoverable plastics reveals that only 2.4 percent is recycled. This a rticle presents a flowsheet that we developed and tested in a bench-sc ale pilot plant. It shows that a combination of mineral processing tec hniques, including comminution, heavy media separation, and flotation, can be successfully adapted to the recycling of post-consumer plastic s. The gamma potation process, which operates on the basis of solution surface tension control to facilitate the separation of inherently hy drophobic solids, combined with the alkali-treatment of a mixed polyvi nal chloride-polyethylene terephthalate feedstock generates clean poly mer concentrates at high recoveries.