Abstract
A solvent extraction system based on the ionic liquid tricaprylmethylammonium nitrate, [A336][NO3], has been investigated for separation of mixtures of rare earth elements (REE) at high total REE concentrations (up to 2 M). The chelating agent EDTA was added to the aqueous nitrate feed solution to increase the separation factors (SFs). This improvement of the SFs is based on the fact that [A336][NO3] extracts the light REE (LREE) stronger than the heavy REE (HREE), whereas a chelating agent forms more stable complexes with the HREE than with the LREE. The combination of these two effects makes that the LREE are even more efficiently extracted than in the absence of a chelating agent. The most efficient separation of the LREE La–Nd from the other REE was obtained using a total initial REE concentration of 1 M, an EDTA concentration of 0.2 M, and a total nitrate concentration of 11 M. Stripping of the extracted REE from the ionic liquid phase could be done using water.
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References
Dietz M (2006) Ionic liquids as extraction solvents: Where do we stand? Sep Sci Technol 41:2047–2063. doi:10.1080/01496390600743144
Kolarik Z (2013) Ionic liquids: How far do they extend the potential of solvent extraction of f-elements? Solvent Extr Ion Exch 31:24–60. doi:10.1080/07366299.2012.700589
Liu Y, Chen J, Li D (2012) Application and perspective of ionic liquids on rare earths green separation. Sep Sci Technol 47:223–232. doi:10.1080/01496395.2011.635171
Earle MJ, Seddon KR (2000) Ionic liquids, green solvents for the future. Pure Appl Chem 72:1391–1398. doi:10.1351/pac200072071391
Wellens S, Thijs B, Binnemans K (2012) An environmentally friendlier approach to hydrometallurgy: highly selective separation of cobalt from nickel by solvent extraction with undiluted phosphonium ionic liquids. Green Chem 14:1657–1665. doi:10.1039/C2GC35246J
Mikhailichenko AI, Goryacheva EG, Sokolova NP, Aksenova NM, Vdovina LV, Emelyanov AP (1984) Extraction of rare-earth elements from chloride solutions by salts of quaternary ammonium bases. Sov Radiochem 26:25–29
Khopkar PK, Mathur JN (1981) Extraction of trivalent actinides and lanthanides by tertiary and quaternary amines from concentrated chloride solutions. J Inorg Nucl Chem 43:1035–1040. doi:10.1016/0022-1902(81)80170-4
Larsson K, Ekberg C, Ødegaard-Jensen A (2012) Using Cyanex 923 for selective extraction in a high concentration chloride medium on nickel metal hydride battery waste. Hydrometallurgy 129–130:35–42. doi:10.1016/j.hydromet.2012.08.011
Černá M, Volaufová E, Rod V (1992) Extraction of light rare earth elements by amines at high inorganic nitrate concentration. Hydrometallurgy 28:339–352. doi:10.1016/0304-386X(92)90039-3
Morais CA, Ciminelli VS (2007) Selection of solvent extraction reagent for the separation of europium(III) and gadolinium(III). Miner Eng 20:747–752. doi:10.1016/j.mineng.2007.02.010
Lu D, Horng J, Hoh Y (1989) The separation of neodymium by quaternary amine from didymium nitrate solution. J Less Common Met 149:219–224. doi:10.1016/0022-5088(89)90489-X
Bauer DJ, Lindstrom RE (1971) Differential extraction of rare-earth elements in quaternary ammonium compound-chelating agent systems. Bureau of Mines Report of Investigations 7524
Komasawa I, Hisada K, Miyamura M (1990) Extraction and separation of rare-earth elements by tri-n-octylmethylammonium nitrate. J Chem Eng Jpn 23:308–315. doi:10.1252/jcej.23.308
Preston J (1996) The recovery of rare earth oxides from a phosphoric acid by-product. Part 3. The separation of the middle and light rare earth fractions and the preparation of pure europium oxide. Hydrometallurgy 42:151–167. doi:10.1016/0304-386X(95)00079-V
Bauer DJ, Lindstrom RE (1967) Selective extraction and separation of lanthanides with a quaternary ammonium compound. US Patent 3,323,857
Gaudernack B, Hannestad G, Hundere I (1974) Process for separation of yttrium from lanthanides. US Patent 3,821,352
Trimble C, Strott D (1972) Yttrium purification process. US Patent 3,640,678
Vander Hoogerstraete T, Binnemans K (2014) Highly efficient separation of rare earths from nickel and cobalt by solvent extraction with the ionic liquid trihexyl(tetradecyl)phosphonium nitrate: process relevant to the recycling of rare earths from permanent magnets and nickel metal hydride batteries. Green Chem 16:1594–1606. doi:10.1039/C3GC41577E
Rout A, Binnemans K (2014) Solvent extraction of neodymium(III) by functionalized ionic liquid trioctylmethylammonium dioctyl diglycolamate in fluorine-free ionic liquid diluent. Ind Eng Chem Res 53:6500–6508. doi:10.1021/ie404340p
Larsson K, Binnemans K (2014) Selective extraction of metals using ionic liquids for nickel metal hydride battery recycling. Green Chem 16:4595–4603. doi:10.1039/C3GC41930D
Larsson K, Binnemans K (2015) Metal recovery from nickel metal hydride batteries using Cyanex 923 in tricaprylmethylammonium nitrate from chloride aqueous media. J Sustain Metall 1:161–167. doi:10.1007/s40831-015-0017-5
Larsson K, Binnemans K (2015) Separation of rare earths by split-anion extraction. Hydrometallurgy 156:206–214. doi:10.1016/j.hydromet.2015.04.020
Riano S, Binnemans K (2015) Extraction and separation of neodymium and dysprosium from used NdFeB magnets: an application of ionic liquids in solvent extraction towards the recycling of magnets. Green Chem 17:2931–2942. doi:10.1039/C5GC00230C
Larsson K, Binnemans, K (2014) Applying ionic liquid to rare earth separations. In: Proceedings of the 1st European rare earth resources conference (ERES 2014), Milos, Greece, 4–7 September 2014, p 278–290
ERECON (2015) Strengthening the European rare earths supply-chain: challenges and policy options. In: Kooroshy J, Ties G, Tukker A, Walton A (eds) A report by the European Rare Earths Competency Network (ERECON)
Reed GC (2011) NI 43-101 technical report, Norra Kärr REE—zirconium deposit. Pincock, Allen and Holt, Gränna
Sjöqvist ASL, Cornell DH, Andersen T, Erambert M, Ek M, Leijd M (2013) Three compositional varieties of rare-earth element ore: eudialyte-group minerals from the Norra Kärr alkaline complex, Southern Sweden. Minerals 3:94–120. doi:10.3390/min3010094
Vander Hoogerstraete T, Jamar S, Wellens S, Binnemans K (2014) Determination of halide ions in solution by total reflection X-ray fluorescence (TXRF) spectrometry. Anal Chem 86:3931–3938. doi:10.1021/ac403583u
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The research leading to these results has received funding from the European Community’s Seventh Framework Programme ([FP7/2007–2013]) under Grant Agreement No. 309373 (EUARE). This publication reflects only the authors’ view, exempting the Community from any liability.
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The contributing editor for this article was Bernd Friedrich.
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Larsson, K., Binnemans, K. Separation of Rare Earths by Solvent Extraction with an Undiluted Nitrate Ionic Liquid. J. Sustain. Metall. 3, 73–78 (2017). https://doi.org/10.1007/s40831-016-0074-4
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DOI: https://doi.org/10.1007/s40831-016-0074-4