Status of recycling end-of-life vehicles and efforts to reduce automobile shredder residues in Korea

The present end-of-life vehicle (ELV) recycle rate and management status during the dismantling stage were investigated to aid the establishment of policies for the management of ELVs by surveying information and using the results gained from questionnaires given to dismantlers. The average recycle rate at the dismantling stage was 44% of the mass of a new vehicle and the rest of the ELV was then compressed and transported to shredding companies to recover mainly the iron content, which averaged 38.7% of the mass of a new vehicle. Nonferrous metals such as copper, antimony, zinc, and aluminum accounted for only 1.5%. The automobile shredder residues (ASRs) were composed of light and heavy fluffs and soil/dust and amounted to 15.8% based on the mass of a new vehicle. The dumping of fluff and inorganic residues in landfill sites, however, will be restricted when new regulations are implemented to reduce the disposal amount to less than 5% of a new car, as has been done in European countries and in Japan. The detailed characteristics of ASR were investigated to suggest appropriate means of treatment such as volume reduction or the utilization of thermal technologies to meet future expected enforcement. Also, some concerns on hazardous pollutant release such as that of dioxins while utilizing such thermal treatment methods were considered. The present on-going research and development projects to meet such future management targets are also introduced.     

Washing treatment of automotive shredder residue (ASR)

Worldwide, the amount of end-of-life vehicles (ELVs) reaches 50 million units per year. Once the ELV has been processed, it may then be shredded and sorted to recover valuable metals that are recycled in iron and steelmaking processes. The residual fraction, called automotive shredder residue (ASR), represents 25% of the ELV and is usually landfilled. In order to deal with the leachable fraction of ASR that poses a potential threat to the environment, a washing treatment before landfilling was applied. To assess the potential for full-scale application of washing treatment, tests were carried out in different conditions (L/S = 3 and 5 L/kg_TS; t = 3 and 6 h). Moreover, to understand whether the grain size of waste could affect the washing efficiency, the treatment was applied to ground (<4 mm) and not-ground samples. The findings obtained revealed that, on average, washing treatment achieved removal rates of more than 60% for dissolved organic carbon (DOC), chemical oxygen demand (COD) and total Kjeldahl nitrogen (TKN). With regard to metals and chlorides, sulphates and fluoride leachable fraction, a removal efficiency of approximately 60% was obtained, as confirmed also by EC values. The comparison between the results for ground and not-ground samples did not highlight significant differences.     

Strategies for the enhancement of automobile shredder residues (ASRs) recycling: Results and cost assessment

With reference to the European regulation about the management of End-of-Life Vehicles (ELVs), Directive 2000/53/EC imposes the achievement of a recycling target of 85%, and 95% of total recovery by 2015. Over the last few years many efforts have been made to find solutions to properly manage the waste coming from ELVs with the aim of complying with the targets fixed by the Directive.This paper focuses on the economical evaluation of a treatment process, that includes physical (size and density), magnetic and electrical separations, performed on the light fraction of the automobile shredder residue (ASR) with the aim of reducing the amount of waste to dispose of in a landfill and enhancing the recovery of valuable fractions as stated by the EU Directive. The afore mentioned process is able to enhance the recovery of ferrous and non-ferrous metals of an amount equal to about 1% b.w. (by weight) of the ELV weight, and to separate a high energetic-content product suitable for thermal valorization for an amount close to (but not higher than) 10% b.w. 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 metric 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 of the non magnetic metal 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 thermal valorization and reduce the amount of waste generated from ELV shredding to landfill.     

Brominated flame retardants and heavy metals in automobile shredder residue (ASR) and their behavior in the melting process

The End-of-life Vehicles Recycling Act went into effect on January 1, 2005, in Japan and requires the proper treatment of airbags, chlorofluorocarbons (CFCs), and automobile shredder residue (ASR). The need for optimal treatment and recycling of ASR, in particular, has been increasing year after year because ASR is regarded as being difficult to treat. Dioxin-related compounds, brominated flame retardants (BFRs), heavy metals, chlorine and organotin compounds are all present in high concentrations in ASR. The authors conducted ASR melting treatment tests using a 10-tons/day-scale direct melting system (DMS), which employs shaft-type gasification and melting technology. The results obtained showed that dioxin-related compounds and BFRs were decomposed by this melting treatment. The high-temperature reducing atmosphere in the melting furnace moved volatile heavy metals such as lead and zinc into the fly ash where they were distributed at a rate of more than 90% of the input amount. This treatment was also found to be effective in the decomposition of organotin, with a rate of decomposition higher than 99.996% of the input amount. Via the recovery of heavy metals concentrated in the fly ash, all the products discharged from this treatment system were utilized effectively for the complete realization of an ASR recycling system that requires no final disposal sites.     

Characterization of Shredder Residues generated and deposited in Denmark

This study presents a detailed characterization of Shredder residues (SR) generated and deposited in Denmark from 1990 to 2010. It represents approximately 85% of total Danish SR. A comprehensive sampling, size fractionation and chemical analysis was carried out on entire samples as well as on each individual size fraction. All significant elemental contents except oxygen were analyzed. The unexplained “balance” was subsequently explained by oxygen content in metal oxides, carbonates, sulphates and in organics, mainly cellulose. Using mass and calorific balance approaches, it was possible to balance the composition and, thereby, estimate the degree of oxidation of elements including metals. This revealed that larger fractions (>10 mm, 10–4 mm, 4–1 mm) contain significant amount of valuable free metals for recovery. The fractionation revealed that the >10 mm coarse fraction was the largest amount of SR being 35–40% (w/w) with a metal content constituting about 4–9% of the total SR by weight and the <1 mm fine fraction constituted 27–37% (w/w) of the total weight. The lower heat value (LHV) of SR samples over different time periods (1990–2010) was between 7 and 17 MJ/kg, declining with decreasing particle size. The SR composition is greatly dependent on the applied shredding and post shredding processes at the shredding plants causing some variations. There are uncertainties related to sampling and preparation of samples for analyses due to its heterogeneous nature and uncertainties in the chemical analyses results (≈15–25%). This exhaustive characterization is believed to constitute hitherto the best data platform for assessing potential value and feasibility of further resource recovery from SR.