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