Preparation and Evaluation of High-Purity La^sub 2^O^sub 3

A separation procedure based on extraction chromatography using the di(2-ethylhexyl) phosphoric acid (D2EHPA) impregnated resin, anion exchange with DIAION SA 10 resin, and oxalate precipitation has been developed for the preparation of high-purity La^sub 2^O^sub 3^ in hydrochloric acid media at a high La concentration. The metallic impurities Ce, Pr, Nd, Sm, K, Mg, Ca, Zn, Cu, Co, Mn, Pb, Al, In, and Fe, but not Bi, were removed efficiently from La by extraction chromatography using a D2EHPA impregnated resin. The Bi was separated from the La by anion exchange (DIAION SA 10) separation. Thus, a high-purity LaCl^sub 3^ solution was obtained by anion exchange separation and extraction chromatography. La^sub 2^O^sub 3^ was prepared from the purified LaCl^sub 3^ solution by oxalate precipitation. Glow discharge mass spectrometry was applied for purity evaluation of the prepared La^sub 2^O^sub 3^. The purity of the prepared La^sub 2^O^sub 3^ was more than 99.9998 pct total rare earth oxide. [PUBLICATION ABSTRACT]