Separation of vanadium from iron by solvent extraction using acidic and neutral organophosporus extractants

• Cyanex 923 can separate vanadium (V) from iron (III)
• The molar ratio of Cyanex 923 and vanadium (V) species was found to be one
• D2EHPA can be used for separation of vanadium (IV) from iron (II)
• Two moles of D2EHPA were required for per mole of the extracted vanadium (IV) species

Vanadium is known to produce solutions of complex speciation as a function of vanadium concentration and pH. Various solvent extractants have been tested for vanadium recovery from acidic leachates. This research assesses the selectivity of extraction of vanadium (V & IV) over iron (III & II) in sulphate media using phosphinic acid (Cyanex 272), phosphonic acid (Ionquest 801), phosphoric acid (D2EHPA) and phosphine oxide (Cyanex 923) extractants. Among selected extractants, Cyanex 923 showed the best selectivity for vanadium (V) over iron (III) by extracting of VO2SO4‐ in the system. Moreover, D2EHPA revealed a suitable separation for vanadium (IV) over iron (II) by extracting VO+ 2. None of the extractants tested can be used to separate vanadium (V) over iron (II) or vanadium (IV) over iron (III).