As rechargeable batteries proliferate in everything from cars to smartphones, recycling is becoming a critical issue. Now a team of researchers at the University of South Florida has found a way to use naturally occurring fungi to extract cobalt and lithium from waste batteries.
The scientists presented their work at a recent meeting of the American Chemical Society.
â€œThe idea first came from a student who had experience extracting some metals from waste slag left over from smelting operations,â€ says Jeffrey A. Cunningham, the projectâ€™s team leader. â€œThe demand for lithium is rising rapidly, and it is not sustainable to keep mining new lithium resources.â€
While other methods exist to separate lithium, cobalt and other metals, they require high temperatures and harsh chemicals.
The team dismantles the batteries and pulverizes the cathodes, then exposes the remaining pulp to the fungus. â€œFungi naturally generate organic acids, and the acids work to leach out the metals,â€ Cunningham explains. â€œThrough the interaction of the fungus, acid and pulverized cathode, we can extract the valuable cobalt and lithium. We are aiming to recover nearly all of the original material.â€
The cobalt and lithium remain in a liquid acidic medium after fungal exposure. The next challenge is how to get the two elements out of that liquid. â€œWe have ideas about how to remove cobalt and lithium from the acid, but at this point, they remain ideas,â€ Cunningham says. â€œHowever, figuring out the initial extraction with fungi was a big step forward.â€