Solvent extraction of molybdenum and vanadium from sulphate solutions with Cyphos IL 101

Increasing demand for the rare metals of molybdenum and vanadium stimulates the research on their recovery from various resources. Solvent extraction of molybdenum and vanadium from sulphate solution with Cyphos IL 101 (trihexyl(tetradecyl)phosphonium chloride) in an aromatic diluent of ShellSol A150 was investigated in order to develop a more efficient separation method. It was found that molybdenum was extracted efficiently in the tested pH range of 0.5-2.0, while efficient vanadium extraction was at pH over 1.8. Effective separation of molybdenum from vanadium could be achieved at pH around 0.5. The separation of molybdenum and vanadium from impurities including iron(III) and aluminium was effective. The metal loading capacity was very high due to the formation of polyoxometallic ions during the extraction of molybdenum and vanadium. Chloride up to 10 g/L and sulphate up to 100 g/L had no significant effect on metal extraction. The extraction of molybdenum and vanadium was very fast, reaching equilibrium in 0.5 min. Vanadium could be stripped efficiently using 0.5 M sulphuric acid, while molybdenum could be stripped efficiently using 4-6 M sulphuric acid. The Cyphos IL 101 organic system has obvious advantages compared to the previously investigated solvent systems in terms of separation of molybdenum from vanadium and separation of vanadium from iron(III) and aluminium. Crown Copyright (C) 2015 Published by Elsevier B.V. All rights reserved.