While a shortage of raw rare-earth materials available to the United States draws near, the number of rare-earth-containing products, such as cell phones and hybrid cars, appears to be ever growing. Scrap from the manufacturing of these consumer products contains some rare-earth material, and the products themselves are eventually discarded by their owners. So, could the United States create a new supply stream of rare earths by recycling them from industrial scrap and post-consumer products?
Perhaps. And scientists at the Ames Laboratory are working to improve rare-earth recycling processes.
“We’ll be looking at questions of how you recover rare earths from a wide variety of mixed alloys, at the same time, at a reasonable price, without creating any additional hazardous waste,” says Bill McCallum, a senior materials scientist at Ames Laboratory and part of a team evaluating rare-earth recycling. The end goal may be developing an alternative to current rare-earth alloy separation processes, which start with an oxide form of rare-earth materials. Researchers will be looking to combine some processing steps so non-rare-earth elements can be separated from rare-earth elements in one continuous process
“From a scientific standpoint, we look at the recycling problem and say it’s something we ought to be able to do,” McCallum adds. “Some of the economic factors are out of our control, but as scientists, we can examine and improve the processes. We can then determine their cost and have a starting point for improving economic viability of rare-earth recycling.”
Ames Laboratory brings decades of previous rare-earth research to the challenges of rare-earth recycling. In fact, many rare-earth processing techniques currently in use all over the world were originally developed at Ames Lab.
“The Ames Laboratory has the ability to tap a considerable amount of knowledge that was gained in developing rare-earth processing,” says McCallum. “We have reports, papers and records that other laboratories and researchers do not have access to. In addition, some personnel who are most familiar with the previous research are retired but are still available to consult. This will be true for a relatively narrow window in time. Thus, if we are going to address the rare-earth recycling challenge, the time is now.”
The Ames Laboratory’s research goals in the area of rare-earth recycling include developing a metallic flux process to recover rare earths in magnets, batteries and magnetic refrigerant; developing an efficient process for mixed materials not suitable for metallic flux processes; and modifying current processes to recover rare-earth elements from phosphors, lasers and optical materials.
“But, right now, regardless of whether materials come from discarded post-consumer items or industrial scrap, recycling rare earths faces some economic challenges,” says McCallum.
For instance, in most consumer goods, like laptop computers or hybrid vehicles, the amount of rare earths in products is a relatively small part of the whole. So costs for dismantling a cell phone or a car are prohibitively high in comparison to the potential value of the salvaged rare earths.
The relatively high cost of separating materials also holds true for manufacturing scrap created when rare-earth magnets are produced. Most current manufacturing processes result in some broken magnets and other scrap pieces, all of which contain alloys with high concentrations of rare-earth materials with some potential for recycling.
However, most magnet companies use the same production lines for many different grades of rare-earth magnets, which contain different concentrations of rare-earths. Manufacturers do not currently separate out scrap according to composition because it would introduce additional costs. The result is a mixture of scrap containing a fluctuating blend of alloys, making any potential recycling process difficult.
“Even if this mixed material is separated, the resulting material is not very usable in preparing new alloy because it is oxidized,” said McCallum. “For now, it’s cheaper to dump rare-earth manufacturing scrap in a landfill than to attempt to separate the scrap alloy, let alone attempt to separate out the rare-earth elements in the alloy for reuse.”
But, as the volume of rare-earth materials in use in the United States and elsewhere grows and the supply of virgin rare earths dwindles, recycling discarded rare earths may become appealing and perhaps necessary. “We know that if we can bring down the cost and increase the efficiency of rare-earth recycling, it will tip the balance toward increased recovery of rare earths,” says McCallum.
~ by Breehan Gerleman Lucchesi