| Abstract Scope |
Bauxite ores used in aluminium oxide production via the Bayer process contain trace elements (REEs, V, Li, Sc, Ga) currently not valorised. Vanadium and Gallium dissolve during the Bayer process forming impurities in the Bayer liquor (sodium aluminate). Vanadium application ranges from steel to aircraft industries, and extraction involves ammonium treatment of strip liquor for vanadium salt (AMV,V2O5) precipitation. Current crystallization techniques have drawbacks of generating voluminous, highly saline wastewater. This study investigates alternative techniques for high purity vanadium crystallization in temperature-controlled jacketed batch reactors using synthetic solutions whose vanadium concentration (20-50 g/L) mimicked strip liquors. Different precipitants induced supersaturation whose control was investigated by varying; precipitant concentration and addition rate, agitation rate, and seeding. Precipitate analysis identified vanadium salts, yield, purity, morphology, and composition using ICP-OES, SEM-EDS and XRD. Initial results show techniques with low, well controlled supersaturation produce high purity, regular shaped vanadium salts synonymous with growth domination.
The authors greatly acknowledge the EIT KIC upscaling project VALORE (2022 – 2024, www.kic-valore.eu) under the Grant Agreement n° 21018 which has as main objective the development of an innovative metallurgical process that enables the separation, extraction and valorization of purified V and Ga as side products from the Bayer process in alumina refineries |