Recovery of valuable fractions from automobile shredder residues (ASRs): perspectives and cost evaluation

Automobile shredder residue (ASR, also called fluff) is the waste generated from end-of-life vehicles (ELVs) after shredding and metal separation steps. Directive 2000/53/EC imposes the achievement of a recycling target of 85% and 95% of total recovery by 2015. By that time only 5% of a vehicle will be admitted in a landfill and no more than 10% will undergo thermal recovery. Aim of this paper is to carry out an economical evaluation of a treatment process performed on the light fraction of the ASR with the aim of reducing the amount of waste to dispose of in a landfill and trying to meet the goals stated by Directive 2000/53/EC. This process, that includes the phases of 4-mm sieving, magnetic separation, electrostatic separation and a two-phase (2 kg/dm3 and 1 kg/dm3 density values) densimetric separation, is able to enhance the recovery of metals (ferrous and non-ferrous) of an amount equal to about 1% of the ELV weight, and to separate a high energetic-content product to send to thermal valorization for an amount close to (but not higher than) 10% of the ELV weight. The results of the economical assessment led to annual operating costs of the treatment ranging from 300,000 €/y to 350,000 €/y. Since the considered plant treats about 13,500 tons of ASR per year, this would correspond to an operating cost of approximately 20 - 25 €/t. Taking into account the amount and the selling price of the scrap iron and amagnetic metal (as a mixture of copper, brass, aluminum and magnesium) recovered by the process, thus leading to a gain of about 30 €/t per ton of light ASR treated, the cost of the recovery process is balanced by the profit from the selling of the recovered metals. On the other hand, the proposed treatment is able to achieve the fulfillment of the targets stated by Directive 2000/53/EC concerning the amount of an ELV that can undergo thermal valorization and reduce the amount of waste generated from ELV shredding to dispose of in landfill.