New process for recycling rare earth metals

Scientists at Deakin University and Spain’s Tecnalia research and innovation hub 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.

Project leader, Dr Cristina Pozo-Gonzalo, from Deakin’s Institute for Frontier Materials (IFM), said there was 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,” Dr Pozo-Gonzalo said.

“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 – which include elements such as cerium, praseodymium, neodymium, and lanthanum – was creating pressure on global supply chains.

“To add to concerns, almost 85 per cent of the world’s REM primary resources are in China, where the government has restricted exports for periods of time in the recent past, threatening 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, the researchers use ionic liquids to recover the rare earth metals from the resulting solution using a process of electrodeposition.

This new method for recovering REMs has great potential and minimises the generation of toxic and harmful waste. It is also easy to implement.

REMs are among the top critical raw materials identified by the European Commission, Geoscience Australia and the US Department of Energy.

Their efficient recovery from recycled materials is becoming increasingly important, given that only about 3–7 per cent of REMs are currently recovered from end-products because of technological difficulties.

The 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 Dr Cristina Pozo-Gonzalo, storEnergy Director Professor Maria Forsyth, and platform leader Professor Jennifer Pringle, Dr Matthias Hilder; and Tecnalia Research and Innovation researchers Laura Sanchez-Cupido, Amal Siriwardana and Ainhoa Unzurrunzaga.

The full findings, “Water-Facilitated Electrodeposition of Neodymium in a Phosphonium-Based Ionic Liquid”, have been published in The Journal of Physical Chemistry Letters.