Solvent and Reversed-Phase Extraction Chromatographic Separation of Niobium, Zirconium, and Hafnium with Aliquat 336

Abstract Aliquat 336 has been employed as an effective anionic extractant for the radiochemical separation of niobium, zirconium, and hafnium in mixtures using solvent extraction and reversed phase extraction chromatography (RPEC). In solvent extraction, niobium and zirconium are extracted with reagent solutions in the respective concentration ranges <0.001–0.04 mol dm−3 and 0.5 mol dm−3 leaving hafnium in the aqueous phase. In RPEC, niobium and zirconium are extracted by the reagent impregnated column and hafnium is completely eluted with water. Zirconium and niobium subsequently are eluted successively with 0.5 mol dm−3 HNO3 and 1 mol dm−3 HF solutions. Distribution studies indicate that the extracted species for niobium and zirconium are respectively mono- and dinegative in charge. The extent of separation and the purity of the separated species were verified by means of gamma-ray spectrometry.