Potential New Rare Earth Elements Supply from Phosphoric Acid
Researchers continue to develop new technologies to recover rare earth elements (REEs), an essential component in consumer electronic products. X-ray fluorescence technology is an important tool in the rare earth element recycling industry because handheld XRF analysers can help detect lead, mercury, and cadmium in electronics such as printed circuit board (PCB) finishes, leads, terminations, solder and internal/external interconnects, keeping these toxic metals out of the recycling stream and future products. XRF analysers are also used to positively identify the chemical composition of numerous metal alloys. Finally, handheld XRF analysers are useful instruments for REE exploration because they can provide real-time, on-site assays of REEs and other elements in any type of geological samples.
A new REE recycling technology developed by Precision Periodic involves using a nano-filtration system to extract and separate rare earth metals from phosphoric acid and waste. As reported in Mining.com, the filter captured 40-60% of the rare earth elements and radioactive elements in a five-minute single pass-through from wet-process phosphoric acid and 80% of the rare earth elements in a five-minute single pass-through from sulfuric acid leached waste.
“The successful test projects proved that the Thor nano-filtration technology could be a game-changer for US production of its own rare earth elements supply,” Brian Andrew, CEO of Precision Periodic, said in the media statement. “The phosphoric acid contains 150 ppm of total rare earths. Based on our extraction capabilities, we could extract 75 grams of total rare earths out of every 1,000 litres of phosphoric acid from a phosphate mine. This equates to one Florida phosphate mine being able to produce 230 metric tons of total rare earths per year which would supply an estimated 25% of the annual US Military needs.”
Other notable recycling efforts include a project to recover rare earths such as europium, cerium and lutetium from LED bulbs without using any chemicals, according to mining.com.
Phys.org described on a REE recycling project underway at Kanazawa University in Japan to extract yttrium and europium from spent phosphors in fluorescent lamps.
Agmetalminer.com reported that a team of researchers at Worcester Polytechnic Institute may have developed both a technically and commercially viable means for recycling 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 fibre membranes, organic solvents, and neutral extractants to selectively recover rare earth elements.
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.
The National reports that researchers at the Masdar Institute of Science and Technology are interested in developing magnets that could replace the most common form of rare-earth magnet, namely those that contain neodymium. 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.
Phys.org reports that scientists are recycling magnets by the melt spinning process, also known as rapid solidification, a method already tried and tested for other alloys. The scientists are now optimising the properties of the recycled magnets by varying the melt spinning process.