In 2019, the world generated 54.6 million tons of e-waste. However, just 17.4 percent of it was formally collected and recycled. Since 2014, the amount of e-waste recycled has grown by 1.8 million tons—a relatively small amount, considering that the amount of e-waste generated increased by 9.2 million tons in the same period.
Global reserves of some elements, such as platinum, are supposed to be fully used up within 15 years if the proportion of recycled stocks entering production doesn't increase. E-waste and EV batteries are currently recycled through processes called pyrometallurgy (火法冶金术) and hydrometallurgy (湿法冶金术). However, they involve burning temperatures with a high energy demand and deep carbon footprint, and poisonous chemicals which are harmful to the environment. Alternatives are therefore being sought.
A team of scientists from the University of Coventry are extending one such alternative. They have been using non-poisonous bacteria to oxidize and recover the precious metals—a process known as "bioleaching". They have shown that copper is widely recoverable from e-waste, and that all metals present in EV batteries can be recovered by using microbes (微生物). If extended, bioleaching facilities would mean that manufacturers of EV batteries and other electronic goods would be able to recover metals locally, relying less on costly exports to recycling centers abroad.
"At present, a key limitation for e-waste recycling is the lack of certification detailing the types and amounts of metals contained in electronic goods. But with an efficient recycling process appearing, manufacturers have the motivation to use more recycled material in their products, which will change the very design of electronics goods. It's about closing the loop of a product's life cycle," said the leader of the Bioleaching Research Group, Sebastien Farnaud.
Ultimately, bioleaching technology is born out of the idea of creating a truly circular process for the things that we consume. We need to shift from a mindset and economy where we see waste as an end product, to one where there isn't even a start or an end at all.
