Measurement of concentrations of tramp elements in shredder scrap and Automobile Shredder Residue (ASR) and their mass balance analyses

Contamination of undesirable tramp metals in steel scraps from end-of-life vehicles has been of interest for many years. In this work, typical 5 mini-vehicles and 5 small-size passenger cars were dismantled and put into shredder process, in which most of the parts end-of-life vehicles were removed thoroughly before shredding process. The weights of removed parts, shredder scrap, separated non-ferrous metals and automobile shredder residue (ASR) were measured to figure out the mass balances of the end-of-life vehicles. Then, the concentration of Cu, Cr, Sn in shredder scraps and ASRs were measured. It was found that the concentrations of Cu, Cr, Sn in shredder scrap were 0.078%, 0.004%, 0% for mini-vehicles, and 0.08%, 0.015%, 0.001% for small-size passenger cars. On the other hand, relatively high concentrations of Cu, Cr, Sn in ASR were observed, which was 0.42-0.85%, 0.03-0.04%, 0.05-0.06% for mini-vehicles, and 0.59-0.74%, 0.02%, 0.04-0.15% for small-size passenger cars, respectively. It was found that most of Cu contained in the end-of-life vehicles were removed before shredding process.