Efficient recovery of neodymium and praseodymium from NdFeB magnet-leaching phase with and without ionic liquid as a carrier in the supported liquid membrane

In this study, the presence and absence of ionic liquids as a carrier in the SLM system was investigated for the extraction of praseodymium and neodymium ions from the NdFeB magnet-leaching solution. The rate of permeability coefficient in the ion transport process inside the supported liquid membrane was studied by utilizing the variation in the acidity of the source and stripping phases and the role of different carriers in the transport. The highest permeability coefficients were obtained with the synergistic system containing [C6MIM][NTf2], TOPO, and TPB extractants. The higher efficiency is related to the particular ionic property in the extraction of rare earth ions compared with TOPO, and TBP extractants diluted in kerosene. The experimental data of the acidity of the source and stripping phases showed that the neutral pH similar to 6 in the feed phase and the average acidity of 1.8 M nitric acid in the stripping phase were suitable for the transport of ions between both phases. The kinetics of ion transport inside the ionic liquid membrane based on logarithmic variations showed that the process of ion transfer inside the membrane follows the first-order kinetics. The investigation of stability with ionic liquids indicated that a more stable system was provided with ionic liquid as a green solvent in the carrier phase.