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

Abstract

The End-of-life Vehicles Recycling Act went into effect on January 1, 2005, in Japan and requires the proper treatment of airbags, chlorofl uorocarbons (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 diffi cult to treat. Dioxin-related compounds, brominated fl ame 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 gasifi cation 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 fl y 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 fl y ash, all the products discharged from this treatment system were utilized effectively for the complete realization of an ASR recycling system that requires no fi nal disposal sites.Key words Direct melting system (DMS) · ASR · Brominated fl ame retardants · Heavy metal J Mater Cycles Waste Manag (2008) 10:93-101

An international comparative study of end-of-life vehicle (ELV) recycling systems

“…Also, the amount of PCBs was highest at 78,510 lg/kg. With regards to PCBs, Low POP Content is PBDDs/DFs lg/kg 10-120 [6,29] MoBrPCDDs/DFs lg/kg ND-15 [6,29] Brominated diphenyl ethers lg/kg 310,000 [6] PBDEs lg/kg 110,000-310,000 [29] Tetrabromobisphenol A lg/kg 220-15,000 [6,29] HBCD lg/kg 990-5,700 [29] TBP lg/kg 68-180 [29] set at 50 ppm under the Basel Convention on the Control of Transboundary Movements of Hazardous Wastes and their Disposal [105]. ASR may be possibly treated in an environmentally sound manner as a waste contaminated with PCBs.…”

“…Specifically, the control of POPs contained in the residues is the main point of consideration in ASR management. Osada et al [6] carried out a test of melting ASR by using a shaft-type direct melting furnace to determine the behavior of BFRs and PBDD/DFs and the distribution of heavy metals in the slag and fly ash. Table 8 shows the concentrations of dioxin-related compounds and BFRs in a full-scale ASR melting plant.…”

“…Heavy metals and flame retardants with persistent organic pollutants (POPs), often remain in ASR and may induce unintentional generation of POPs during the thermal treatment processes. This is also the reason why recycling ASR is difficult [6].…”

Pyrolysis and gasification-melting of automobile shredder residue

“…Gasification-melting produces syngas, mainly consisting of CO and H 2 , which can be utilized as fuel gas or raw chemicals after cleaning (Cho et al, 2010;Vermeulen et al, 2012). The shaft-type gasification-melting technology has been proven to be effective in many municipal solid waste applications, and has also been examined for application with ASR (Cho et al, 2010;Osada et al, 2008). In this system, combustible wastes are gasified to produce syngas and incombustible wastes are completely melted at high temperatures in the coke bed of the melting furnace, allowing all slag and metal by-products to be effectively utilized as resources (Osada et al, 2008(Osada et al, , 2009.…”

“…As can be seen, this system consists of the shaft furnace for gasification-melting, produced gas combustor, heat exchanger, semidry reactor (SDR), bag filter, and smokestack. In the shaft furnace, ASR, limestone, and cokes were charged from the top, and then drying, gasification, and melting were performed in order, depending on the temperature and atmosphere (Osada et al, 2008(Osada et al, , 2009. After the furnace, the produced syngas was sampled and analyzed with nondispersive infrared (ND-IR) spectrometry (ZRE; Fuji, Tokyo, Japan), and then discharged through the stack after passing the combustor and the treatment system.…”