Rare earth metals are notoriously hard to separate from one another, due to the similarity of their chemical properties. At present, the complex series of solvent extraction steps to extract rare earths from their ores are only carried out in China. With their increasing utilisation in modern technologies, scientists have been collaborating to develop cleaner less intensive methods of rare earth separation.
Tom Van Gerven and Koen Binnemans of the University of Leuven in Belgium have worked together to combine their expertise and develop a photochemical method for extracting the europium and yttrium from an ionic liquid solution. Both elements are present in their trivalent state, but if europium absorbs light of the correct wavelength (provided by a low pressure mercury lamp) it will reduce to the divalent state and be precipitated out.
Want to know more?
Read the full article in Chemistry World by Jonathan Midgley.
Or, take a look at the original article which is free to access until 8th July 2015:
“Photochemical recycling of europium from Eu/Y mixtures in red lamp phosphor waste streams” by B Van den Bogaert et al., DOI:10.1039/c4gc02140a