TOP 3 research breakthroughs

	Ionic liquid process for Co/Ni separation
	In collaboration with Umicore Research (Olen, Belgium), Prof. Koen Binnemans has developed a new ionic liquid solvent extraction process for separation of cobalt and nickel.
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	Separation of rare earths by split-anion extraction with ionic liquids
	There are two main challenges in the field of separation of rare earths by solvent extraction:
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	Ionic liquid process for recovery of yttrium and europium from fluorescent lamp phosphor waste
	A breakthrough process has been developed to selectively recover the most valuable components of waste fluorescent lamp phosphor powder.
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TOP 3 research breakthroughs

Ionic liquid process for Co/Ni separation

In collaboration with Umicore Research (Olen, Belgium), Prof. Koen Binnemans has developed a new ionic liquid solvent extraction process for separation of cobalt and nickel. Cobalt is efficiently extracted to the ionic liquid phase, while nickel is left behind in the raffinate. The advantages of the new process are: (1) the unprecedented high separation factor (> 50,000), which is nearly an order of magnitude larger than the industrial benchmark processes, and (2) the very easy stripping of cobalt from the ionic liquid phase. The process was demonstrated on a mini-pilot scale in batch reactors and in a continuous process with mixer-settlers. In fact, this study provided the proof-of-principle that ionic liquids can be used on an industrial scale for separation of metals by solvent extraction. References:

• An environmentally friendlier approach to hydrometallurgy: highly selective separation of cobalt from nickel by solvent extraction with undiluted phosphonium ionic liquids Wellens, B. Thijs, K. Binnemans Green Chemistry 14, 1657–1665 (2012). DOI: 10.1039/C2GC35246J

• Continuous ionic liquid extraction process for the separation of cobalt from nickel Wellens, R. Goovaerts, C. Möller, J. Luyten, B. Thijs, K. Binnemans Green Chemistry 15, 3160–3164 (2013). DOI: 10.1039/C3GC41519H

Separation of rare earths by split-anion extraction with ionic liquids

There are two main challenges in the field of separation of rare earths by solvent extraction: (1) the development of a highly selective extraction agent that can remove one rare-earth element from a mixture without co-extraction of the other elements; (2) the development of a process that allows extraction of rare earths from a chloride solution to an organic phase by a solvating extractant. Extraction from chloride solution is preferred by industry because hydrochloric acid is much cheaper than nitric acid, and because waste water treatment is simpler in case of chlorides compared to nitrates. Solvating extractants are the preferred type of extractants, because of the possibility of loading a high concentration of rare earths in the organic phase and the easy back extraction of the rare earths from the organic phase by water instead of strong acids. Within the framework of the FP7 project EURARE on the exploitation of European rare-earth deposits, Prof. Binnemans invented a new process, called “split anion extraction” with makes the extraction of rare earths from a chloride solution possible by extraction with a nitrate ionic liquid via a solvating mechanism. References:

• Separation of rare earths by split-anion extraction Larsson and K. Binnemans Hydrometallurgy 156, 206–214 (2015). DOI: 10.1016/j.hydromet.2015.04.020

• Process for extraction and separation of rare earths by split-anion extraction with ionic liquids Binnemans and K. Larsson Patent application WO 2015106324 A1 (see link here)

Ionic liquid process for recovery of yttrium and europium from fluorescent lamp phosphor waste

A breakthrough process has been developed to selectively recover the most valuable components of waste fluorescent lamp phosphor powder. By means of a functionalised ionic liquid, the red phosphor Y₂O₃:Eu³⁺ (YOX) can be selectively dissolved without affecting the other components in the waste fraction. Of particular interest is the possibility to dissolve Y₂O₃:Eu³⁺ (YOX) without bringing the halophosphate phosphor in solution. The YOX phosphor is rich in the critical elements yttrium and europium and represents more than 70% of the intrinsic value of the lamp phosphor waste. After dissolution, europium and yttrium can be recovered from the ionic liquid phase by precipitation of a mixed yttrium-europium oxalate. At the same time, the ionic liquid is regenerated. By calcination, the oxalate can be transformed into Y₂O₃:Eu³⁺ with the same luminescence properties as a new batch of the lamp phosphor. Oxalic acid is the only chemical that is consumed in this cyclic process. References:

• Rare-earth recycling using a functionalized ionic liquid for the selective dissolution and revalorization of Y₂O₃:Eu³⁺ from lamp phosphor waste Dupont and K. Binnemans Green Chemistry 17, 856–868 (2015). DOI: 10.1039/C4GC02107J

• Process for recovery of yttrium and europium from lamp phosphor waste Binnemans and D. Dupont Patent application WO 2016065433 A1 (see link here)