Recovery of High Purity Vanadium Salts from Bayer Liquor

Bauxite oresBauxite ore used in aluminium oxide production via the Bayer process contain trace elements (REEs, V, Li, Sc, Ga) currently not valorised. VanadiumVanadium and GalliumGallium dissolve during the Bayer process forming impurities in the Bayer liquorBayer liquor (sodium aluminate solution). VanadiumVanadium application ranges from steel to aircraft industries, and extraction involves ammonium treatment of strip liquor for vanadiumVanadium salt (AMV, V2O5) precipitation. Current crystallizationCrystallization techniques have drawbacks of generating voluminous, highly saline wastewater. This study investigated the use of antisolventAntisolvent (acetone) crystallizationCrystallization with synthetic solutions as an alternative to the crystallizationCrystallization and calcination step in the conventional production of high purityPurity vanadiumVanadium salts. The yieldYield, purityPurity, and product characteristics of the crystals for different final organic to aqueous (O/A) ratio at constant addition rate of antisolventAntisolvent at room temperature have been investigated. A batch time-dependent effect was observed with the best product quality, in terms of size and crystal habit (dominated by hexagonal laths), being attained when tb ≤ 2 h at an O/A ratio of 0.5. The early onset of acicular crystal formation and higher yieldsYield (≥ 97%), along with higher impurity incorporation into the solid phase, was observed at an O/A ratio of 0.75, and this was attributed to higher levels of supersaturationSupersaturation.