Selective recovery of dysprosium and neodymium ions by a supported liquid membrane based on ionic liquids

Selective permeation of rare earth metal ions (Dy and Nd) against ferric ion (Fe) was conducted by an ionic liquid-based supported liquid membrane (SLM). A novel extractant N,Ndioctyldiglycol amic acid (DODGAA) was employed as the mobile carrier because the DODGAA is readily soluble in ionic liquids such as l-octyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([Cgmim][Tf ₂N]) and shows good selectivity to the rare earth metal ions and efficient stripping behavior. Quantitative transport of Dy and Nd was successfully achieved through the SLM impregnated with the [Cgmim][Tf ₂N] containing DODGAA. Ferric ions were transported at the 10 % level, and Dy and Nd were selectively recovered to the receiving phase. The results suggested a potential use of the SLM system proposed in this study for the recovery of the rare earth metals from leaching magnet scrap which produces leach liquor containing a large amount of Fe.