Rare earth materialsSimplifying recycling of rare-earth magnets
Despite their ubiquity in consumer electronics, rare-earth metals are, as their name suggests, hard to come by. Mining and purifying them is an expensive, labor-intensive and ecologically devastating process. Researchers have now pioneered a process that could enable the efficient recycling of two of these metals, neodymium and dysprosium. These elements comprise the small, powerful magnets that are found in many high-tech devices. In contrast to the massive and energy-intensive industrial process currently used to separate rare earths, the new method works nearly instantaneously at room temperature and uses standard laboratory equipment. Sourcing neodymium and dysprosium from used electronics rather than the ground would increase their supply at a fraction of the financial, human and environment cost.
Despite their ubiquity in consumer electronics, rare-earth metals are, as their name suggests, hard to come by. Mining and purifying them is an expensive, labor-intensive and ecologically devastating process.
Researchers at the University of Pennsylvania have now pioneered a process that could enable the efficient recycling of two of these metals, neodymium and dysprosium. These elements comprise the small, powerful magnets that are found in many high-tech devices. In contrast to the massive and energy-intensive industrial process currently used to separate rare earths, the Penn team’s method works nearly instantaneously at room temperature and uses standard laboratory equipment.
Sourcing neodymium and dysprosium from used electronics rather than the ground would increase their supply at a fraction of the financial, human and environment cost.
A Penn release reports that the research was led by Eric J. Schelter, assistant professor in the Department of Chemistry in Penn’s School of Arts & Sciences, and graduate student Justin Bogart. Connor A. Lippincott, an undergraduate student in the Vagelos Integrated Program in Energy Research, and Patrick J. Carroll, director of the University of Pennsylvania X-Ray Crystallography Facility, also contributed to the study.
It was published in Angewandte Chemie, International Edition.
“Neodymium magnets can’t be beat in terms of their properties,” Schelter said. “They give you the strongest amount of magnetism for the smallest amount of stuff and can perform at a range of temperatures.”
These thermal qualities are achieved by mixing neodymium with other elements, including the rare-earth metal dysprosium, in different ratios. Because those ratios differ based on the application the magnet is being used for, the two metals need to be separated and remixed before they can be reused.
“It’s, in principle, easier to get the neodymium and dysprosium out of technology than it is to go back and mine more of the minerals they are originally found in,” Schelter said. “Those minerals have five elements to separate, whereas the neodymium magnet in a wind turbine generator only has two.”
Currently, whether purifying the neodymium and dysprosium out of minerals or out of an old power tool motor, the same costly and energy-intensive process is used. The technique, known as liquid-liquid extraction, involves dissolving the composite material and chemically filtering the elements apart. The process is repeated thousands of times to get useful purities of the rare-earth metals, and so it must be conducted on an industrial scale.
