Chemists from institutions of the Russian Academy of Sciences have developed new absorbent materials for the selective extraction of rare earth metals from industrial production waste.
The process uses a substance called "Tudga extractor" (octyl diglycolamide), according to the press service of the Russian Ministry of Science and Higher Education.
The press service noted that "researchers from the Center for Rational Use of Rare Earth Mineral Raw Materials of the Frumkin Institute of Physical and Electrochemical Chemistry, in collaboration with colleagues from the Federal Research Center for Physical Chemistry and Medicine of the Russian Academy of Sciences, have synthesized a series of SIR-1-4 adsorbents, which are characterized by their synthetic availability and ease of regeneration. The developed adsorbents, based on the well-known extractant tetraoctyl diglycolamide (TUDGA) and the porous matrix, a styrene-diphenyl copolymer of type LPS-500, have demonstrated high efficiency in the selective extraction of rare earth elements from recycled raw materials."
The press service confirmed that global demand for rare earth metals is currently on the rise. This is due to the essential use of these materials in numerous sectors, such as their use as catalysts in the chemical industry. This increased demand has already depleted traditional raw material sources, leading to higher prices. This, in turn, has spurred the search for new methods of obtaining rare earth elements from other sources, both natural, such as wastewater from mining facilities and mine drainage solutions, and technological, ranging from solutions used in the production of phosphate fertilizers to permanent magnets , which were not previously considered promising sources.
Among the secondary sources of rare earth elements, spent permanent magnets are of particular importance. Their processing is a crucial aspect of the environmental strategy for recycling damaged electronic devices, such as hard drives, audio systems, and vibratory motors in mobile phones, the number of which increases year after year. In this context, neodymium-iron-boron (NdFeB) alloy is one of the best raw materials found in permanent magnets.
The process of extracting rare earth elements from NdFeB-containing magnets begins with the stage of dissolving the magnet scrap in inorganic acids, including nitric acid and sulfuric acid.
One of the new adsorbent materials manufactured by scientists at the Institute of Physical and Electrochemical Chemistry, called SIR 3, opens up new horizons for this extraction process thanks to its unique properties. It surpasses the foreign counterpart of the Trischem DGA type in terms of adsorption capacity and allows for the efficient extraction of rare earth elements from complex mixtures.
Using the SIR 3 adsorbent, scientists developed a method to separate iron ions and the total rare earth elements and typical solutions resulting from the treatment of NdFeB magnets, in order to extract rare earth metals such as neodymium, praseodymium and dysprosium .
