WaterSolutions Separation of Group VB from Liquid Media

Water/Wastewater: Vanadium, niobium, and tantalum are present as cations in acid, so a strong acid cation resin like DOWEX™ G-26 (H) resin is the separation media of choice. In HCl, V(IV) has a high affinity for a strong acid cation resin under dilute acid conditions that diminish at about 4 to 8 M HCl then increase as acid concentrations increase. In perchloric acid, a strong acid cation resin has an even higher affinity of these cations. In dilute nitric acid, V(IV), has a high affinity for DOWEX G-26 (H) resin and is eluted with higher concentrations of nitric acid.

NOTICE: Oxidizing agents such as nitric acid attack organic ion exchange resins under certain conditions. This could lead to anything from slight resin degradation to a violent exothermic reaction (explosion). Before using strong oxidizing agents, consult sources knowledgeable in handling such materials.

In HF and HCl, these elements also form anions that can be captured on a strong base anion exchange resin like DOWEX 21K XLT resin (1). A process for Niobium and Tantalum recovery has been described (2).

Often these metals are being separated from other closely associated metals so resins with the maximum number of theoretical plates are needed. Strong acid cation fine mesh resins like DOWEX 50WX8 100-200 or DOWEX 50WX4 100-200 resins are proposed for this separation.

References

1. "Resin Selectivity in Dilute to Concentrated Aqueous Solutions" by R.M. Diamond and D.C. Whitney, Chapter 8 of Ion Exchange – A Series of Advances Edited by J.A. Marinshy, Published by Marcel Dekker, Inc., New York (1966).

2. "Ion exchange separation processes for Niobium and Tantalum." Barney, Duane L. and Kent, Clifford E., I&EC Process Design and Development 7 (1), 1-5 (1968).