Research Projects

Neodymium is one of the crucial rare earth elements enormously used in magnets, smart phones, catalysts, light emitting diodes, electronic displays and alloys. Estimate shows that India has one-fifth of world’s total rare earth reserves in the form of monazite ore. The mined neodymium values are being exported to Japan as mixed rare earth chloride. On the other hand, we import refined neodymium based products which incurs loss of money. Lack of indigenous separation technology and process technique is the reason for our inability to separate neodymium from its immediate neighbouring element praseodymium and other rare earth elements. It is high time to develop separation strategies for the separation of neodymium in pure form to save our economy. Conventional solvent extractants such as alamine 336, aliquat 336, primene, di-2-ethylhexyl phosphoric acid (D2EHPA), ethylhexyl phosphonic acid mono-2-ethylhexyl ester, cyanex 272, tri-n-butyl phosphate, naphthenic acid, etc. are used to separate neodymium by solvent extraction technique. However, it is very difficult to separate as the chemistry of all rare earth elements is similar due to lanthanide contraction and consequently several stages are required to achieve high separation factor. Moreover, saponification of extractants consumes several tonnes of base (NaOH) which leads to pollution of water bodies and incurs treatment cost to the industries. Also, the solubility of saponified extractant is less in aliphatic solvents which complicates extraction processes. On the other hand, ionic liquids are suitable green alternatives with better performance than conventional solvents. Extraction of rare earths using ionic liquids provides a promising pathway for sustainable environment as it does not require saponification. They also reduce the extractant loss and limits the requirement of organic diluents. The selectivity of metal extraction is dictated by steric hindrance, electron density and orientation of functional groups as well as substituents present in ionic liquids. Therefore, tailoring the substituents present in the molecule of ionic liquids will enhance the separation of rare earths. This project aims at the synthesis of various amine based ionic liquids with various substituents and investigate their potential for the separation of neodymium from praseodymium. The synthesis procedures would be optimized for high yield of ionic liquids. Furthermore, extraction and stripping studies would be performed to optimize process conditions for the efficient separation of neodymium.