Valorization of the automobile shredder residues by thermal route

International audienceThe automobile shredder residues “ASR” represents a heterogeneous material generated during the shredding process of the end-of-life vehicles “ELV”. The ASR, while reactive enough to be classified as hazardous waste, could be considered as a source of energy and reducing agents, since it contains an appreciated combustible hydrocarbon matter, especially plastics. In this context, the present work provides an alternative approach for the thermal valorization of the ASR in iron and steel making operations.Plastics and ASR samples from an European automobile shredder company were collected and their thermal behaviors were studied at temperatures lower than and or equal to 900 °C. Appropriated mixtures of these samples with iron oxides were isothermally treated between 300 °C and 1050 °C for different reaction times. Initial samples as well as solid reaction products were subjected to different analysis methods. The direct reduction of hematite into metallic iron, at 1000-1050 °C, by plastics and ASR hydrocarbons was proved. The reduction steps, the possible reaction mechanisms and the behavior of several tramp and harmful elements were also discussed. Experimental results and thermodynamic predictions suggest that the thermal route can be a promised choice for the valorization of the wasted organic materials. Thermal processing overcome the difficulties and costly operations related to the ultimate removal of lead, zinc and copper compounds by physical means from these wastes. Reactions of chlorine, coming especially from PVC, with these metallic compounds generate their respective chlorides which are volatilized at relatively low temperatures leaving behind an appropriate matter to be introduced in different units of iron metallurgy