March 26, 2013 by Editorial Staff
Belgium: Researchers at Belgium's University of Leuven are using ionic liquids to recycle old magnets and are aiming to apply the process to rare-earth metals.
'The process involves the liquid-liquid extraction of rare-earth metals from the other elements present in neodymium-iron-boron and samarium-cobalt magnets,' explains Koen Binnemans who leads the group developing the process. Meanwhile, these other elements - including iron, cobalt, manganese, copper and zinc - are extracted into the ionic-liquid phase, leaving the rare-earth metals behind in the aqueous phase, he adds.
The ionic liquid itself, trihexyl tetradecyl phosphonium chloride, can also be reused after the transition metals have been successfully recovered. This approach is ‘far more environmentally friendly’ compared to traditional methods that require flammable and volatile solvents such as kerosene, the researchers point out.
At present, the usefulness of neodymium and samarium in the microelectronics industry is countered by their lack of availability, with the European Commission having placed them on a list of critical raw materials.
The Binnemans-led team intends to extend its work on model systems to real-world samples from end-of-life industrial magnetics. Though less than 1% of rare-earth elements are recycled, he estimates that roughly 20% of global demand could be met in this way. ‘Recycling is only a partial solution to the supply-risk problem,’ asserts Binnemans, but he believes that ‘by combining mining and recycling the Western World could become largely independent of China in the future’.
For more information, visit: www.kuleuven.be
Source: Chemistry World