Liquid-liquid extractive separation of molybdenum(VI) in malonate solutions with high relative molecular mass amines

Abstract

Molybdenum can be quantitatively extracted with 0.08 M Amberlite LA-2 in xylene at pH 3.0 from 0.02 M malonic acid, stripped with 0.25 M ammonia solution and determined spectrophotometrically with Tiron at 390 nm. Four other liquid anion exchangers were examined as possible extractants and extraction of molybdenum was found to be quantitative over a limited pH range with two of these. Eight common solvents were tested as diluents; of these, hexane, cyclohexane, benzene and xylene were found to be satisfactory.

Molybdenum can be separated from elements that do not form complexes with malonic acid by prior stripping of the extract with water. The metal can be separated from elements forming weak complexes by selective stripping with acids. A novel feature of the method is the separation of molybdenum from multi-component mixtures.

The method has been applied to the determination of molybdenum in steel and soil.