A way to recover rare earths from electric motors’ magnets

THE MOTORS driving today’s use powerful magnets made from . Not all rare earths are actually that rare. Neodymium, for instance, is about as abundant as tin. But good, workable deposits are scarce, and many are in China, which has, in the past, imposed export quotas. This, combined with an absence of substitutes, make rare earths pricey enough to constitute more than half of such a motor’s cost. Yet virtually none is recycled—a deficiency that extends also to the motors in computer hard drives, cordless tools and domestic appliances, and to the generators (essentially, electric motors in reverse) in wind turbines.The problem, says Allan Walton, who leads the Magnetic Materials Group at the University of Birmingham, in Britain, is that the process of shredding and separating usually applied to electronic waste makes the recovery of rare earths hard. Rare-earth magnets are brittle, and break into particles which oxidise readily in air. The result is a residue which is of little, if any, commercial value.