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)