Scientists create new process for recycling rare earth metals

Scientists at Deakin University and Spain’s Tecnalia Research and Innovation have improved the process for recovering rare earth metals (REMs), which are essential in mobile phones and other modern technologies such as hybrid electric cars.

Deakin Institute for Frontier Materials (IFM) researcher Dr Cristina Pozo-Gonzalo, who leads the electromaterials project, said there is an urgent need to develop a cleaner and simpler process for recovering REMs, as current extraction methods generated huge amounts of toxic and radioactive waste.

“Consumption of REMs has been gradually increasing since the 1960s due to their use in electronics, optics and magnetics, making them ubiquitous in everyday applications such as television screens and computer systems,” said Dr Pozo-Gonzalo. “They’re also a key component of many modern technologies, including hard disk drives, clean technologies such as wind power turbines, and batteries for hybrid electric vehicles.”

She said increased demand for REMs — including elements such as cerium, praseodymium, neodymium and lanthanum — is creating pressure on global supply chains.

“To add to concerns, almost 85% of the world’s REM primary resources are in China, where their government has restricted exports for periods of time in the recent past, endangering availability and price stability,” Dr Pozo-Gonzalo said. “There’s growing concern that future access to these materials won’t be reliable, leading to them being targeted for reclamation and recycling. The primary extraction and processing methods for REMs are also energy-intensive processes that lead to the excessive generation of toxic and radioactive waste. We need a real alternative.

“After separating the metals from their end-of-life product, our team uses advanced electrolytes known as ionic liquids (liquid salt-based systems) to recover the rare earth metals from the resulting solution using a process of electrodeposition —when you use a low electric current to cause metals to reform and deposit on a desired surface.

“This new method for recovering REMs has great potential and minimises the generation of toxic and harmful waste. We are also aiming for a method that can easily be implemented widely across the world.”

Dr Pozo-Gonzalo said REMs are among the top critical raw materials identified by the European Commission, Geoscience Australia and United States Department of Energy.

“The efficient recovery of REMs from recycled materials is becoming increasingly important, given that only about 3–7% of REMs are currently recovered from end products because of technological difficulties,” she said.

“Our work addresses a key knowledge gap in the REM recycling process, and is an important early step towards establishing a clean and sustainable processing route for REMs and alleviating the current pressures on these critical elements.”

The project is a collaboration between Deakin IFM researchers Dr Cristina Pozo-Gonzalo, Professor Maria Forsyth, Associate Professor Jennifer Pringle and Dr Matthias Hilder, and Tecnalia Research and Innovation researchers Laura Sanchez-Cupido, Amal Siriwardana and Ainhoa Unzurrunzaga.

Their full findings have now been published in The Journal of Physical Chemistry Letters.