![]() Called froth flotation, it was originally developed to separate acrylonitrile- butadiene-styrene (ABS) from high-impact polystyrene (HIPS) a mixture of plastics that is typical of that recoverable from obsolete appliances. But shredder residue content has overlapping densities and shapes which make it difficult to get enough material with the right purity for scrap processors.Īrgonne’s new process is designed to efficiently separate polymers of equivalent densities. These methods will work on certain thermoplastics. Existing separation technologies for polymer recovery rely on differences in density to separate solid particles. In the last 15 years, however, both automobiles and white goods have increasingly used polymers and composites. That’s because recycling efforts were driven by the value of the metal - the single largest source of recycled ferrous scrap for the iron and steel industry is obsolete automobiles. Unfortunately, this byproduct has historically ended up in landfills. For each ton of metal a shredding facility recovers there is roughly 500 lb of shredder residue. It’s typically a mix of polymers (plastics, rubber, and polyurethane foam), a “fines” fraction that includes metal oxides, glass, and dirt, as well as residual amounts of ferrous and nonferrous metals. Once the metals are gone, what’s left is called shredder residue. Trommels and screens are then used to remove particles smaller than about 5/8 in., followed by one or more stages of eddy-current separations to recover the nonferrous metals. Processing-unit operations vary but the basic process involves air classification of the “lights” fraction followed by one or more stages of magnetic separation to recover the ferrous metals. Household appliances, industrial scrap, and demolition debris are all candidates for being turned into fist-sized chunks as a means of liberating the metals. Scrap processors use giant 3,000 to 8,000-hp hammer mills to shred both vehicles and other obsolete metal-containing products. (ACC-PD), is developing technology for recycling polymeric materials from shredder residue. Argonne, working with the Vehicle Recycling Partnership (VRP) of the United States Council for Automotive Research (USCAR), a partnership between General Motors, Ford Motor Co., and Chrysler, and the American Chemistry Council-Plastics Div. The percentage of recycled materials from vehicles is about to go up. Other components such as batteries, automotive fluids, some windshield glass, starters, alternators, and other dismantled parts are also recycled. ![]() Nearly 75% of the weight of the vehicles is metals and the metals are profitably recycled through direct reuse, component remanufacturing, and scrap processing or shredding. The good news, say researchers at Argonne National Laboratory (Argonne), is that over 95% of the over 50 million vehicles scrapped globally each year enter a comprehensive recycling infrastructure. Consider the mix of materials that go into household appliances and automobiles.
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