The Role of Plastics in Automotive Shredder Residue (ASR): Characterization and Environmental Assessment

Following the recovery of resalable parts through selective dismantling of end-of-life vehicles (ELVs), the remaining automobile hulks are today shredded in hammer mills to facilitate the recovery of ferrous and non-ferrous metals. Large household appliances (white goods) and other light metal scrap are often co-shredded with ELVs. The residue from this industrial operation is called automotive shredder residue (ASR) and is predominately landfillled in Europe and the United States. In the present study, several real-world samples of ASR from automobiles-only and mixed-metal shredding were carefully hand-sorted into as many as 17 separate fractions and analyzed to ascertain the distribution of heavy metals and other materials. The study emphasized the plastic and rubber fractions with an interest toward increased recovery of these materials. Although residual metals, other inorganics, and heavy metals exist throughout ASR, the work reported here shows that the plastics fractions are for the most part relatively low in heavy metal content. Cadmium, tin, and antimony from plastics predominate in the total ASR. These results suggest that the environmentally sound management of plastics from ELVs and ASR should not be overly problematic and that a range of ASR processing and recovery options can be explored for technical and economic feasibility.