The selective separation of neodymium from aluminum using ion flotation

Abstract

In this study, fluorine ion was applied as a chelating agent to separate selectively neodymium ion from aluminum ion by ion flotation. The interactions of neodymium and aluminum ions with fluorine ions at different fluorine concentrations and pHs were investigated to determine species ions formed in solution. The results showed that the presence of fluorine ions increased the selective separation of neodymium ion, enhancing the selectivity coefficient during the process. A decrease in the selectivity coefficient was obtained with increasing the concentration of fluorine ion. As the fluorine ion concentration increased from 3.5 to 10 mM, there was an increase in the selectivity coefficient from 2.91 to 30.2 and then decreased using more fluorine. Selective ion flotation results indicated that neodymium ion recovery was higher than that of aluminum ions, indicating the ion recovery order based on the enhancing order of crystal ionic radius. Also, the scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDAX) and Fourier-transform infrared spectroscopy (FTIR) analyses results confirmed higher interaction of fluorine ions with neodymium ions compared to that of the aluminum ions in the solution.