Extracted Species of Rare Earth Elements Using Bis(1,1,3,3-tetramethylbutyl)phosphinic Acid as an Extractant and Their Effective Mutual Separation by High-Performance Extraction Chromatography

摘要

The possible extracted species of rare earth elements (REE) in bis(1,1,3,3-tetramethylbutyl)phosphinic acid (Hmbp)/cyclohexane-HNO_3 system was proposed by a log-log plot analysis and a saturated extraction method as being [m(mbp)_3(Hmbp)_3] (M=REE). It was also verified by IR, ~1H MR spectra and element analysis of lutetium-Hmbp extracted species. The effective mutual separation of REEs was achieved on the Hmbp modified C-18 column by a pH gradient elution. Moreover, the degree of the mutual separation of europium(III) from gadolinium(III) was remarkably improved by adding glycollic acid in the mobile phase. A fine concentrate of Sm_2O_3, Eu_2O_3, and Gd_2O_3 from a rare earths smeltery was analyzed by the present method with the spectrophotometric detection after postcolumn derivatization with Arsenazo III.