Researchers at Kyoto University in Japan are investigating the selective dismantling of certain components from used vehicles to increase the recycling potential of precious metals.
Discarded automobiles have become a ‘promising’ secondary resource pool for precious metals for researchers at Kyoto University and their work focuses on gold and silver, platinum, palladium and rhodium. It is a huge market. In 2010, global automobile ownership and annual end-of-life vehicles (ELVs) exceeded one billion units, with 40 million added each year.
Could we reach 83%?
Between 33% and 53% of precious metals present in ELVs were recycled in Japan in 2015. This could be boosted to between 62% and 83%, according to the university specialists. They have reported their innovative ‘selective dismantling’ process in the journal Environmental Science & Technology. This approach was found to be effective for printed wiring boards (PWBs) and heating wires in automotive rear windows.
The content of precious metals per ELV in Japan will range from 2-6 grams by 2040, notes professor Guochang Xu. He says the annual amount of precious metals in all ELVs ‘will remain largely stable’ at 14–15 tonnes. However, the proportions of precious metals used in the different vehicles, parts and components will gradually change. Specifically, more will occur in the PWBs of next-generation vehicles.
Nevertheless, it has proved difficult to date to efficiently recycle all precious metals in this growing waste stream because many car components are shredded. As a result, the precious metals content is ‘highly diluted’ in the fractions from complex shredders.
Xu says that modern industrialised ELV recycling systems tend to focus on the collection of catalysts while neglecting other valuable components such as PWBs. As the global automotive industry moves toward ‘greener’ and ‘smarter’ practices, fewer catalysts and more PWBs will be required.
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