Experimental study and optimization of effective parameters on extraction Praseodymium and Neodymium from simulated NdFeB magnet-leaching solutions using Bis (2,4,4-trimethylpentyl) phosphinic acid

Praseodymium (Pr) and neodymium (Nd) are among the rare earth elements that have received significant attention due to their many applications. In this research, the separation of Pr and Nd from simulated NdFeB magnet leaching solutions with Cyanex 272/kerosene was modeled and optimized. Response surface methodology (RSM) based on the central composite design (CCD) was applied to fit the polynomial equation to the experimental data. The effects of variables such as concentration of Cyanex 272 (0.23-0.57 mol.L-1), pH (2.0-5.0) and O/A (1-3) on the extraction efficiency and separation factor of Pr and Nd were studied. The order of the effect of the variables on the extraction efficiency was opposite to the effect of the variables on the separation factor. The numerical optimization was performed to maximize the operational selectivity of the studied system. The calculated results for Nd and Pr extraction percentages were 71.7% and 62.5%, respectively and the separation factor was 1.54. Also, it was found the stripping of Pr and Nd ions from the loaded organic phase can be effectively conducted under the 0.1 mol/L hydrochloric acid solution within a contact time of 5 min conditions. The studied system showed an efficient performance in both extraction and striping processes of Pr and Nd at investigated condition.