Our post, Rare Earth Element Recycling: Is There Hope After All? discussed a potential solution for recycling the rare earth elements neodymium, dysprosium and praseodymium from the drive units and motors of discarded electric and hybrid cars. Another emerging technology, reported on the Oak Ridge National Laboratory web site, simplifies the process of recycling critical materials from electronic waste by using a combination of hollow fiber membranes, organic solvents, and neutral extractants to selectively recover rare earth elements.
Here we continue the discussion with a look at some emerging technologies to recycle rare earths from magnets, or in some cases, to eliminate them altogether. Magnets are what make electric motors work. According to engadget, Honda has co-developed a new hybrid motor with Daido Steel that doesn’t use heavy rare earth metals like dysprosium and terbium, instead relying on magnets from Daido Steel that cost and weigh less than the previous components.
Researchers looking for alternatives to rare earth elements include two scientists at the Masdar Institute of Science and Technology who are looking for new combinations of chemical elements, including iron, aluminum and manganese, that have magnetic properties and are resistant to stresses such as high temperature. The National reports the researchers are particularly interested in developing magnets that could replace the most common form of rare-earth magnet, namely those that contain neodymium, which is used in an alloy also containing iron and boron. The technology involves high-throughput screening to identify promising compositions, followed by an analysis of the physical properties, including the magnetic energy product, of the compositions. New magnets with a medium energy product are likely to be fully characterized and ready for commercial applications within two to three years. High-value magnets will likely to take four to five years.
Finally, phys.org reports that scientists from the Fraunhofer Project Group for Materials Recycling and Resource Strategies IWKS in Alzenau and Hanau of the Fraunhofer Institute for Silicate Research ISC are trying to recycle magnets by the the melt spinning process, also known as rapid solidification, a method already tried and tested for other alloys. The scientists have already recycled magnets and are now optimizing the properties of the recycled magnets by varying the melt spinning process.
X-ray fluorescence technology is also a help in the rare earth element recycling industry. Portable XRF analyzers can help detect if electronics, including printed circuit board (PCB) finishes, leads, terminations, solder and internal/external interconnects, contain restricted substances. This technology can help ensure that toxic substances, including lead, mercury, and cadmium, are kept out of the recycling stream and future products.
REE recycling technologies are likely to continue to help keep pace with the anticipated increase in demand for the products they help make, and to supplement the difficult and costly mining process for these metals. Mining REEs is challenging because they rarely exist in pure form; they are usually concentrated in more than one mineral, and each mineral requires a different extraction and processing technology and mineral processing. Geochemical exploration is the main method of REE exploration. Depending on the REE project type, portable XRF analyzers are useful instruments that can provide real-time, on-site assays of REEs and other elements in any type of geological samples.