Extraction and separation of heavy rare earth metals in the presence of diethylenetriaminepentaacetic acid

Abstract

The extraction and separation of heavy rare earth metals (Y/Er and Yb/Lu) by liquid-liquid extraction with 2-ethyl-2-methylheptanoic acid (VA-10) in the presence of diethylenetriaminepentaacetic acid (DTPA) has been investigated. The extraction equilibrium for each heavy rare earth metal with VA-10 is established up to high loading ratios. In the presence of DTPA, the distribution ratios of each metal are decreased by the masking effect. In the Y/Er system, the order of the extractabilities of Y and Er is reversed and the selective extraction of Y is enhanced especially at high pH values, while the separation is little improved in the Yb/Lu system.