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Using automated separation, a mixed plastic stream can be recovered from shredder residue (SR). However, the mixed plastics may be contaminated with dirt, oils, heavy metals, and substances of concern (SOCs). To remove these contaminates from the mixed plastics, the plastics must be washed and cleaned. According to the U.S. Environmental Protection Agency (U.S. EPA), the recovered mixed plastic needs to contain less than 2 ppm of Polychlorinated Biphenyls to be introduced into commerce, thereby setting the performance criteria for the washing systems. This paper describes the performance and safety criteria for the washing systems, the selected washing processes, and the factors contributing to the economy of mixed plastics washing.

Tons of shredder residue (SR), a complex mixture of plastics, foams, rubber, metals, and glass, are generated each year as a by-product from the recycling of obsolete vehicles. The Vehicle Recycling Partnership (VRP), along with our CRADA partners, is investigating ways to enable the optimum recovery and recycling of these materials. This study investigates the feasibility of recycling (PU) foam using a new chemical process by glycolysing [1, 2] two types of polyurethane (PU) foams, “dirty” and “clean”, which were recovered from SR via an industrial scale process specifically designed to separate PU foams from SR [3, 4]. In stage one of this process, the polyurethane foam is subjected to glycolysis, followed by filtration of the liquid glycolyzed product. In stage two, the glycolyzed products are used as initiators in reaction with propylene oxide to prepare novel polyurethane polyols.