TELF AG analyzes a promising new method for the processing of rare earths
The strategic value of these elements
The strategic and industrial importance of rare earths, according to recent reports, could be destined to increase, in particular due to the numerous industrial applications that continue to use rare earths to power electronic devices, artificial intelligence systems and infrastructures related to renewable energy. Nowadays, however, the methods for obtaining high-quality rare earths directly usable by industry are still very complex, and not only because these elements’ refining and processing capacity is still concentrated in very few countries.
The most difficult part of obtaining a pure quality of rare earths is linked, above all, to the separation process, with which the individual rare earths present in a given rock agglomerate are divided and separated from each other and, therefore, made usable for their numerous applications. A key aspect of these important geological resources is represented by the unique properties of each of the 17 elements that make up the rare earths group, which, in addition to making them valid allies for various industrial purposes, also increases the complexity related to the processes aimed at their isolation, their separation.
However, steps forward to simplify this process are being made in various parts of the world and are already bringing promising results. American university researchers recently tested a new method for processing these precious geological resources, including rare earths recoverable from electronic waste.
The potential of the new method
At the moment, rare earths are separated through a peculiar method that combines a water-based solvent with an organic one. In the latter, chemists usually add particular molecules called chelators, which bind to the individual rare earths and promote their subsequent separation (the chelator generally selects the individual rare earths based on their size). Although it is still the most widespread method today, this technique has some obvious limitations, such as the fact that it is still tough to obtain a pure sample of a rare earth element with just a few processing cycles.
The innovation brought to light by the American research team has to do with a new chelator, which has been optimized to make the use of an organic solvent superfluous. The experiment focused on a compound of dysprosium and neodymium and on using a specific chelator capable of binding to the larger neodymium atoms. With the addition of sodium bicarbonate, it is possible to obtain dysprosium with the appearance of a carbonate salt, which could then be filtered to obtain the single rare earth element in pure form. After this operation, however, the chelator can be reused to get the pure element.
It is no coincidence that the research authors focused on the elements of dysprosium and neodymium: these resources are often found in electronic waste from old devices made with some rare earth element, such as neodymium-based magnets. In fact, the possibility of activating new supply chains of rare earths by taking them directly from waste materials from the electronics sector is being explored in various corners of the world.
