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.