Search Results (14)

The quantity of waste from end-of-life vehicles is increasing with an increase in the number of scrapped internal combustion engine vehicles owing to international trends such as carbon neutrality and particulate matter reduction. The recycling rate must be ≥95%; however, the average recycling rate remains at approximately 89%. Therefore, the improvement of the recycling of automobile shredder residues (ASR) is gaining attention. In this study, four types of products (interlocking, clay, and lightweight swelled ceramic (LSC) bricks, and asphalt paving aggregate (APA)) were manufactured using ASR melting slag (ASRMS). Environmental performance, quality standards, and technology were evaluated to assess the recyclability of the manufactured bricks. The interlocking brick substituted melting slag for sand and stone powder as an aggregate. As melting slag content increased, absorption decreased and bending strength increased. Clay brick was manufactured by replacing kaolin and feldspar with melting slag that substituted for 20%. The quality of clay bricks mixed with over 15% melting slag was not better than standard. Asphalt paving aggregate was used to investigate the optimum condition of slag content in mixed asphalt; the mixture ratio showed that 61% broken stone of 13 mm, 6% screenings, 10% melting slag, 15% sand and 8% filler was most effective. A lightweight swelled ceramic brick was manufactured by using melting slag, front glass, and so on. Specific gravity and compressive strength ranged from 0.38 to 0.51 and from 339.7 to 373.6 N/cm². ASRMS exhibited an environmental performance suitable for recycling and the manufactured bricks satisfied the quality standards. The recyclability of ASR was also assessed in terms of waste usage, conformance to quality standards, market size, and demand prediction. APA showed the best results followed by interlocking, clay, and LSC bricks. Full article

In this study, we investigated the applicability of an automobile shredder residue (ASR) as an energy and recycling resource. First, ASR gasification was conducted in a fixed-bed reactor (throughput = 1 kg/h) at different temperatures (800, 1000, and 1200 °C) and an equivalence ratio of 0.1–0.5. Clay bricks were prepared with the solid residue obtained from the gasification process to address the issue of solid-residue production in pyrolysis. The syngas (H₂ + CO) from ASR gasification had maximum and minimum yields of approximately 86 and 40 vol.%, respectively. Furthermore, the yield of syngas increased with the temperature and equivalence ratio (ER); therefore, the optimum conditions for the ASR gasification were determined to be a temperature of 1200 °C and an ER of 0.5. In addition, solid residues, such as char and ash, began to melt due to thermal heating in the range of 1300–1400 °C and were converted into melting slag, which was subsequently used to manufacture clay bricks. The absorption ratios and compressive strengths of the clay bricks were compared to those set by Korean Industrial Standards to evaluate the quality of the clay bricks. As a result, the manufactured clay bricks were estimated to have a compressive strength of over 22.54 N/mm² and an absorption ratio of less than 10%. Additionally, greenhouse gas (GHG) emissions from the melting–gasification process were estimated and compared with those from ASR incineration, calculated using the greenhouse gas equations provided by the Korean Ministry of Environment. As a result, it was revealed that the GHG emissions from the combined melting–gasification process (gasification, melting system, and clay-brick manufacturing) were approximately ten times higher than those from the ASR-incineration process. Thus, in terms of operation cost on the carbon capture process for GHG reduction, the combined melting–gasification process would be a more efficient process than that of incineration. Full article

The sustainable resource management of end-of-life vehicles (ELVs) towards a circular economy has become an issue of concern around the world. An understanding of recycling and the quantitative flow of ELVs is important because of their potential for resource recovery as well as the environmental impacts posed by their toxic chemicals upon disposal. In this paper, the generation and recycling system of ELVs in South Korea has been discussed based on a review of the available statistics and literature and site visits to ELV-recycling facilities. A material-flow analysis (MFA) for ELVs was performed to elucidate the resource recovery from recycling, while the substance flow of polybrominated diphenyl ethers (PBDEs) in automobile shredded residues (ASR) was also determined for proper management. Approximately one million tons of ELVs in 2020 were processed by dismantling and shredding treatment for the recovery of reusable and recyclable materials (803,000 tons), resulting in 78,300 tons of ASR. Approximately 97 tons of PBDEs as flame retardants were generated mainly from ASR in 2020 and processed via combustion, either with energy recovery (59.8%) or without heat recovery (39.2%). The monitoring of brominated dioxins and furans by unintentional release during the incineration processes of ASR is required in order to prevent the dispersion of the chemicals in the environment. Full article

Automobile shredder residue (ASR) pyrolysis produces solid, liquid, and gaseous products, particularly pyrolysis oil and gas, which could be used as renewable alternative energy resources. Due to the primary pyrolysis reaction not being complete, the yield of gaseous product is low. The pyrolysis tar comprises chemically unstable volatiles before condensing into liquid. Understanding the characteristics of volatile products will aid the design and improvement of subsequent processes. In order to accurately analyze the chemical characteristics and yields of volatile products of ASR primary pyrolysis, TG–FTIR–GC/MS analysis technology was used. According to the analysis results of the Gram–Schmidt profiles, the 3D stack plots, and GC/MS chromatograms of MixASR, ASR, and its main components, the major pyrolytic products of ASR included alkanes, olefins, and alcohols, and both had dense and indistinguishable weak peaks in the wavenumber range of 1900–1400 cm⁻¹. Many of these products have unstable or weaker chemical bonds, such as =CH–, =CH2, –C=C–, and –C=CH2. Hence, more syngas with higher heating values can be obtained with further catalytic pyrolysis gasification, steam gasification, or higher temperature pyrolysis. Full article

Pyrolysis and gasification have gradually become the main means to dispose of automobile shredder residue (ASR), since these methods can reduce the volume and quality of landfill with lower cost and energy recovery can be conducted simultaneously. As the ASR pyrolysis process is integrated, the results of pyrolysis reactions of organic components and the interaction among polymeric components can be clarified by co-pyrolysis thermogravimetric experiments. The results show that the decomposition mechanisms of textiles and foam are markedly changed by plastic in the co-pyrolysis process, but the effect is not large for rubber and leather. This effect is mainly reflected in the pyrolysis temperature and pyrolysis rate. The pyrolytic trend and conversion curve shape of the studied ASR can be predicted by the main polymeric components with a parallel superposition model. The pyrolytic product yields and characterizations of gaseous products were analyzed in laboratory-scale non-isothermal pyrolysis experiments at finished temperatures of 500 °C, 600 °C, and 700 °C. The results prove that the yields of pyrolytic gas products are determined by the thermal decomposition of organic substances in the ASR and final temperature. Full article

The separated and sorted combustibles from automobile shredder residue (ASR) can be pyrolyzed and used as a heat source or liquefied to produce materials with added value. In this study, the thermal decomposition properties of ASR were determined and thermal kinetic studies were performed. Four types of raw materials were separated from ASR and mixed at a constant ratio: 38.5 wt.% of plastic; 31.6 wt.% of fiber; 17.3 wt.% of sponge; and 12.3 wt.% of rubber. Pyrolysis kinetics analysis was carried out using the Thermogravimetric analysis-derivative thermogravimetry (TGA-DTG) technique and activation energy were calculated by differential and integral isoconversional model methods, Flynn-Wall-Ozawa (FWO), Kissinger-Akahira-Sunose (KAS), and Friedman. Thermogravimetric analysis was performed under nitrogen with four temperature rate conditions from room temperature to 800 °C. In the thermal degradation profile, peaks representing mass loss rates were observed for each sample at different temperature ranges. It was observed that the final mass reduction temperature in the mixed samples was lower than in the individual samples. The activation energies of plastics and rubbers were 105.39 kJ/mol and 115.20 kJ/mol respectively. The sponge foams and fibers were 172.59 kJ/mol and 160.30 kJ/mol respectively. The mixed sample had an activation energy value of 159.56 kJ/mol. The basic physicochemical and pyrolysis characteristics of ASR were examined to be used as basic data for the recycling of ASR for future pyrolysis. Full article

In a global market characterized by the trend of saving non-renewable resources, recycling has become one of the key factors that alleviates the rarity of resources and preserves existing ones. One of the largest industries that consumes natural resources is the automotive industry. This includes not only resource consumption but also the environmental effects of each new unit produced in this industry. As a result, recycling end-of-life vehicles has become an increasingly obvious and widespread concern. This paper proposes a preliminary analysis of the dismantling/recycling activities in Romania compared to other economies (e.g., USA). It aims to determine the impact that dismantling end-of-life vehicles has, according to the legislation in the field, on the economy and the environment. In order to obtain a complete picture, it is obvious that further research is needed. Full article

The treatment of end-of-life vehicles generates large amounts of automobile shredder residue (ASR), a potential source of recycled metals. Reliable measurement methods are required to determine the composition of ASR and evaluate the resource potential. We reported on research undertaken to investigate bias and variability in the process of measuring trace metals in ASR. Two primary samples of shredder light fraction (SLF) underwent extensive physical sample preparation and chemical analysis. The samples were spiked to control random variations and systematic effects during physical sample preparation. Chemical analysis was conducted using wavelength-dispersive X-ray fluorescence spectrometry (WD-XRF), a fully validated wet-chemical analysis, and a wet-chemical analysis representing an “in-house” lab procedure. Physical sample preparation introduced deviations up to a factor of 2, likely due to preferential losses and heterogeneity. Deviations for WD-XRF measurements of elements were in the range +100%/−50%. In-house chemical analysis produced results that were in good agreement with validated results for Al, Fe and Sn, but led to biased results or high variability for Cd, Dy, La, Nd, Pb, Pd, Pt and Sb. To improve the chemical analysis of trace metals in SLF, we recommended reducing particle size to less than 0.1 mm before chemical analysis and using a larger number of repeated digestions. Full article

There is increasing demand for an efficient technique for separating automobile shredder residue (ASR) obtained from end-of-life vehicles (ELVs). A particular challenge is the physical separation of conductive materials from glass. In this study, the performance of pretreatment and induction electrostatic separation process was evaluated. The results show that a sieving/washing (combination of sieving and washing) pretreatment was the most effective for removing conductive material compared to electrostatic separation alone. The optimum separation efficiency of copper products was achieved with an applied voltage of 20 kV, a relative humidity of less than 35%, and a splitter position of 8 cm. Although the separation efficiency was slightly reduced when some small glass particles remained attached to the conductive materials, the separation efficiency of copper from the pretreated ASR dramatically increased to 83.1% grade and 90.4% recovery, compared to that of raw ASR (34.3% grade and 58.6% recovery). Based on these results, it was demonstrated that the proposed sieving/washing pretreatment was proficient at removing conductive materials from glass; thus, it has the potential to significantly improve the efficiency of electrostatic separation for ASR. Full article

With the increase the worldwide consumption of vehicles, end-of-life vehicles (ELVs) have kept rapidly increasing in the last two decades. Metallic parts and materials of ELVs can be easily reused and recycled, but the automobile shredder residues (ASRs), of which elastomer and plastic materials make up the vast majority, are difficult to recycle. ASRs are classified as hazardous materials in the main industrial countries, and are required to be materially recycled up to 85–95% by mass until 2020. However, there is neither sufficient theoretical nor practical experience for sorting ASR polymers. In this research, we provide a novel method by using S-Band microwave irradiation together with 3D scanning as well as infrared thermal imaging sensors for the recognition and sorting of typical plastics and elastomers from the ASR mixture. In this study, an industrial magnetron array with 2.45 GHz irradiation was utilized as the microwave source. Seven kinds of ELV polymer (PVC, ABS, PP, EPDM, NBR, CR, and SBR) crushed scrap residues were tested. After specific power microwave irradiation for a certain time, the tested polymer materials were heated up to different extents corresponding to their respective sensitivities to microwave irradiation. Due to the variations in polymer chemical structure and additive agents, polymers have different sensitivities to microwave radiation, which leads to differences in temperature rises. The differences of temperature increase were obtained by a thermal infrared sensor, and the position and geometrical features of the tested scraps were acquired by a 3D imaging sensor. With this information, the scrap material could be recognized and then sorted. The results showed that this method was effective when the tested polymer materials were heated up to more than 30 °C. For full recognition of the tested polymer scraps, the minimum temperature variations of 5 °C and 10.5 °C for plastics and elastomers were needed, respectively. The sorting efficiency was independent of particle sizes but depended on the power and time of the microwave irradiation. Generally, more than 75% (mass) of the tested polymer materials could be successfully recognized and sorted under an irradiation power of 3 kW. Plastics were much more insensitive to microwave irradiation than elastomers. With this method, the tested mixture of the plastic group (PVC, ABS, PP) and the mixture of elastomer group (EPDM, NBR, CR, and SBR) could be fully separated with an efficiency of 100%. Full article

Automobile-shredder-residue (ASR) recycling techniques have been widely applied for improving the total recycling rate of end-of-life vehicles. In this study, to obtain useful information for predicting or improving ASR-separation efficiency, trajectory analyses of conductors (copper) and non-conductors (glass) were performed using a lab-scale induction electrostatic separator. The copper-wire trajectories obtained showed a good agreement depending significantly on the electric field strength and particle size. The observed copper-wire trajectories showed consistent congruity with the coarse-particles simulation (0.5 and 0.25 mm). The observed fine-particles (0.06 mm) trajectory was deflected toward the (−) attractive electrode, owing to the charge density effects due to the particle characteristics and relative humidity. This results in superior separation performance because more copper enters the conductor products bin. The actual dielectric-glass trajectory was deflected toward the (−) attractive electrode, thus showing characteristics similar to conductive-particle characteristics. Through analyses conducted using a stereoscopic microscope, scanning electron microscope, and energy dispersive spectroscope, we found heterogeneous materials (fine ferrous particles and conductive organics) on the glass surface. This demonstrates the separation-efficiency decrease for non-ferrous metals during electrostatic separation in the recycling of ASR. Future work should include a pretreatment process for eliminating impurities from the glass and advanced trajectory-simulation processes. Full article

This paper concentrates on a study of a novel multi-sensor aided method by using acoustic and visual sensors for detection, recognition and separation of End-of Life vehicles’ (ELVs) plastic materials, in order to optimize the recycling rate of automotive shredder residues (ASRs). Sensor-based sorting technologies have been utilized for material recycling for the last two decades. One of the problems still remaining results from black and dark dyed plastics which are very difficult to recognize using visual sensors. In this paper a new multi-sensor technology for black plastic recognition and sorting by using impact resonant acoustic emissions (AEs) and laser triangulation scanning was introduced. A pilot sorting system which consists of a 3-dimensional visual sensor and an acoustic sensor was also established; two kinds commonly used vehicle plastics, polypropylene (PP) and acrylonitrile-butadiene-styrene (ABS) and two kinds of modified vehicle plastics, polypropylene/ethylene-propylene-diene-monomer (PP-EPDM) and acrylonitrile-butadiene-styrene/polycarbonate (ABS-PC) were tested. In this study the geometrical features of tested plastic scraps were measured by the visual sensor, and their corresponding impact acoustic emission (AE) signals were acquired by the acoustic sensor. The signal processing and feature extraction of visual data as well as acoustic signals were realized by virtual instruments. Impact acoustic features were recognized by using FFT based power spectral density analysis. The results shows that the characteristics of the tested PP and ABS plastics were totally different, but similar to their respective modified materials. The probability of scrap material recognition rate, i.e., the theoretical sorting efficiency between PP and PP-EPDM, could reach about 50%, and between ABS and ABS-PC it could reach about 75% with diameters ranging from 14 mm to 23 mm, and with exclusion of abnormal impacts, the actual separation rates were 39.2% for PP, 41.4% for PP/EPDM scraps as well as 62.4% for ABS, and 70.8% for ABS/PC scraps. Within the diameter range of 8-13 mm, only 25% of PP and 27% of PP/EPDM scraps, as well as 43% of ABS, and 47% of ABS/PC scraps were finally separated. This research proposes a new approach for sensor-aided automatic recognition and sorting of black plastic materials, it is an effective method for ASR reduction and recycling. Full article

The purpose of this feasibility research was to study a novel sensor based separation method for recycling of plastic materials from end-of-life vehicles (ELVs) by using eigen-frequency response of impact acoustic emission. In this research three kinds of commonly used plastics, polypropylene (PP), acrylonitrile-butadiene-styrene (ABS), and styrene-maleic-anhydride (SMA) sampled from end-of-life vehicles, were researched. Almost all the crushed plastic scraps had a flake structure, theoretically their impact response behaviors were determined by their diameters and thicknesses. The equivalent diameters of the scraps were characterized by fine sieving and their thicknesses were measured online by a 3D laser triangulation sensor above the conveying path. Following this the scraps were free dropped one-by-one to impact with an impact passive body on which impact acoustic emission (AE) signals were generated and acquired by an acoustic pickup sensor. Thirdly, the AE signals which carried eigen-frequency response features were processed and characterized. Results demonstrated that the scraps with diameters < 8 mm were too weak for the actual devices to process; the scraps with diameter from 8–13 mm still generated quite a lot of AE signals of inadequate intensity. Finally the general characterization and recognition yields were 64.6%, 61.7%, and 63.9% of PP, ABS, and SMA in mass, respectively of tested materials. Full article

Plastics are increasingly a preferred material choice in designing and developing complex, consumer products, such as automobiles, because they are mouldable, lightweight, and are often perceived to be highly recyclable materials. However, actually recycling the heterogeneous plastics used in such durable items is challenging, and presents very different scenarios to how simple products, such as water bottles, are recovered via curbside or container recycling initiatives. While the technology exists to recycle plastics, their feasibility to do so from high level consumer or industrial applications is bounded by technological and economical restraints. Obstacles include the lack of market for recyclates, and the lack of cost efficient recovery infrastructures or processes. Furthermore, there is a knowledge gap between manufacturers, consumers, and end-of-life facility operators. For these reasons, end-of-life plastics are more likely to end up down-cycled, or as shredder residue and then landfilled. This paper reviews these challenges and several alternatives to recycling plastics in order to broaden the mindset surrounding plastics recycling to improve their sustainability. The paper focuses on the automotive sector for examples, but discussion can be applied to a wide range of plastic components from similarly complex products. Full article