Abstract:The extraction of Eu³⁺ from chloride medium using bifunctional ionic liquid extractants (Bif-ILEs) tri-n-octylmethyl ammonium bis(2-ethyl hexyl) phosphate ([A336][D2EHP]) and trihexyltetradecyl phosphonium bis(2-ethylhexyl) phosphate ([P₆₆₆₁₄][D2EHP]) in kerosene was studied to develop environmentally friendly extraction process. The extraction behavior of Eu³⁺ was examined by varying key process parameters. The extraction behavior indicates that ammonium-based ionic liquid [A336][D2EHP] shows better extraction efficiency of Eu³⁺ than that of phosphonium-based ionic liquid [P₆₆₆₁₄][D2EHP]. Quantitative extraction of Eu³⁺ is obtained with 0.05 mol/L [A336][D2EHP], whereas, 0.1 mol/L of [P₆₆₆₁₄][D2EHP] is required to achieve the same extraction rate of Eu³⁺. The extraction process is endothermic with respect to [A336][D2EHP]. Stripping experiments indicate that 100% of Eu³⁺ can be back extracted from both the loaded ionic liquids using 20 vol.% HNO₃. The highest separation factor (β_Y/Eu) of 653.59 is reported at pH of 3.2, and the separation factor of Eu³⁺ over La³⁺ is 30.6 at the same pH. From the leach liquors of waste tube light powder, 99.98% of Eu and 99.99% Y are recovered using 0.2 mol/L [A336][D2EHP] in 2-stage cross current extraction with aqueous to organcic ratio (O/A) of 1:1 and 1:2.

Key words: europium; bifunctional ionic liquid; solvent extraction; separation; phosphor powder