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)

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