Recovery of Nd and Pr from NdFeB magnet leachates with bi-functional ionic liquids based on Aliquat 336 and Cyanex 272

•Ionic liquid (R4NCy) used for Nd and Pr recovery from waste NdFeB magnet.•R4NCy extracts more REEs than individual extractants(Aliquat336 and Cyanex272).•Nd and Pr extracted in 2 stages at 1:1 phase ratio with R4NCy at pH 2.5.•Extraction of Nd and Pr was 98.97% and 99.02%, respectively.•The extracted species was MCl3 ⋅ 3R4NCy.

The separation of neodymium and praseodymium was carried out from a chloride solution containing the similar composition of NdFeB magnet leach liquor. A comparative study between extractants demonstrated that the extraction efficiency of bi-functional ionic liquids (Bif-ILs) tri octylmethylammonium bis(2,4,4-trimethylpentyl)phosphate (R4NCy) and trioctylmethylammonium di(2-ethylhexyl)phosphate (R4ND) was higher than the conventional extractants such as tri-octyl methyl ammonium chloride (Aliquat 336), bis(2,4,4-trimethylpentyl) phosphinic acid (Cyanex 272) and di-2-ethylhexyl phosphoric acid (D2EHPA) under same experimental condition. The extraction efficiency of different extractants for Nd and Pr was in the order: R4NCy > R4ND > Cyanex 272 > D2EHPA > Aliquat-336. As the extraction of Nd and Pr was maximum with R4NCy Bif-ILs, the McCabe-Thiele diagram was constructed with R4NCy which showed 2 stages at 1:1 phase ratio. A 2-stage counter current simulation study showed 98.97% Nd and 99.02% Pr extraction. The loaded organic phase was stripped with H2SO4 acid and the stripping efficiencies for Nd and Pr were 98.11% and 98.75%, respectively. The extracted species was found to beMCl3 ⋅ 3R4NCy. The thermodynamic parameters were also determined for extraction of Nd and Pr with ionic liquid.