Fusion-extraction technique of vanadium(III) using ammonium phosphate salt as flux

Abstract

This study presents an alternative fusion method for sample dissolution and extraction of vanadium from an inorganic (V2O3) compound and mineral ore sample (AMIS 0501) using phosphate salts as flux. Complete sample dissolution was achieved at 800 °C within ±20 min using both the sodium and ammonium phosphate flux. The precipitation of vanadium was subsequently achieved after the fusion of the sample using ammonium phosphate flux, and no precipitate was obtained using sodium phosphate flux. The differences in cations between the two fluxes (NH4+ and Na+) influenced the precipitation of vanadium. The XRD analysis of the precipitate from V2O3 using ammonium phosphate showed a monoclinic structure of vanadium (III) tris(metaphosphate) (V(PO3)3) compound, which belonged to the Ic space group with lattice parameters a = 10.6071, b = 19.0871 and c = 9.4230. A remarkable vanadium recovery of 98% was obtained from inorganic compounds, V2O3, and up to 70% from the AMIS mineral ore sample using the ammonium phosphate flux method. The vanadium precipitates from AMIS contained Fe (20.97%) and Ti (44.97%), which occurred as impurities in the recovery of vanadium using the ammonium phosphate flux method.