Precipitation Behavior of Lanthanoid(III) Complexes with 2, 6-Diacetylpyridine Bis(benzoylhydrazone) in Methanol and Application to Mutual Separation of Neodymium and Holmium

Abstract

The precipitation behavior of lanthanoid(III) ions (La-Ho except for Pm) has been studied in methanol by the use of 2, 6-diacetylpyridine bis(benzoylhydrazone) as a precipitant. The recoveries of Gd and Tb were very low compared with other lanthanoids. Rough separation of the lighter and heavier lanthanoid groups has also been examined using the (Nd+Ho)-mixed solution. For the initial solution with 0.1-9.0 of the Nd/Ho molar ratios, decontamination factors (DF) of Nd in the precipitate were estimated as 0.4-12.5, whereas those of Ho remained in the solution were estimated as 0.5-17.5. The precipitant was recovered almost completely as a metal-free form by adding the aqueous EDTA solution to the precipitate and the filtrate.