Thermal Treatment and Valorization of Automotive Shredder Residue

Automotive shredder residue (ASR) comprises the heterogeneous polymeric, rubber, textile and residual glass and metal fines left after the mechanical separation of end-of-life vehicles. Thermal treatment—encompassing pyrolysis, gasification, torrefaction and high-temperature melting–gasification—offers routes to reduce landfill burden, recover energy and reclaim material value. Pyrolysis at 400–800 °C transforms organic fractions into pyrolytic oil, syngas and char, with process parameters such as heating rate, residence time and catalysts determining product yields and quality. Gasification under controlled oxygen or steam generates syngas rich in H₂ and CO, suitable for use as fuel or reducing agent in metallurgical processes, while residual ash or slag can be repurposed in construction materials. Torrefaction at 250–450 °C improves the friability and energy density of the remaining fluff, aiding downstream metal separation. Integrating these thermal pathways with downstream valorisation—for example, refining pyrolysis oil into transportation fuels, employing char as alternative reductant or incorporating molten slag into bricks—underpins a circular-economy approach. Recent advances in reactor design, in-situ analytical techniques and process intensification have propelled ASR valorisation towards technical and economic feasibility, with potential to redirect millions of tonnes of waste from disposal into energy systems and material cycles.

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Thermal Treatment and Valorization of Automotive Shredder Residue publication trend

The graph below shows the total number of articles in thermal treatment and valorization of automotive shredder residue across all publications each year (not limited to Nature Index journals).

Technical terms

Automotive Shredder Residue (ASR): The non-metallic waste stream from end-of-life vehicle shredding, comprising plastics, fibres, rubbers and glass.

Pyrolysis: Thermal decomposition of organic materials in the absence of oxygen to yield char, oil and gas.

Gasification: Partial oxidation of carbonaceous feedstock at elevated temperatures to produce syngas (H₂ and CO).

Torrefaction: Mild thermal treatment under inert atmosphere (250–450 °C) to improve fuel properties and separability.

Syngas: Synthesis gas, a mixture of hydrogen and carbon monoxide used as fuel or feedstock.

Solid Recovered Fuel (SRF): Processed waste material sized and characterised for use as an alternative to conventional fuels.

References

1. Pyrolysis of Automotive Shredder Residue (ASR): Thermogravimetry, In-Situ Synchrotron IR and Gas-Phase IR of Polymeric Components. Polymers (2023).
2. Experimental investigations on reactor scale-up and optimisation of product quality in pyrolysis of shredder waste. Fuel Processing Technology (2003).
3. Alternative Reducing Agents in Metallurgical Processes: Devolatilization of Shredder Residue Materials. Journal of Sustainable Metallurgy (2016).
4. Alternative Reducing Agents in Metallurgical Processes: Gasification of Shredder Residue Material. Journal of Sustainable Metallurgy (2016).
5. Evaluation of the Melting Gasification Process for Recovery of Energy and Resources from Automobile Shredder Residues. Energies (2022).
6. Can torrefaction be a suitable method of enhancing shredder fines recycling?. Waste Management (2021).