Basic Research on Selective Separation of Vanadium and Gallium by lon Exchange Based on Vanadium's Homopolyacid Characteristics

Vanadium and gallium are critical rare metals essential to industrial development, making their selective separation and recovery a priority. This study examines the use of SO42- ion-type D301 resin for the efficient separation and recovery of vanadium and gallium from a Bayer-enriched solution. Through concentration and component predominance diagrams, alkali titration, and Raman spectroscopy, the presence of vanadium polyoxoanions was confirmed. An RSM scientific model was developed to determine optimal adsorption conditions, and various characterization methods were applied to validate the adsorption process. This study found that in Bayer vanadium-gallium-enriched solutions, the optimal pH range for vanadium polyoxoanions is 2-3. Using the Box-Behnken Design (BBD) method, a maximum vanadium adsorption rate of 97.84% was achieved. The separation factors for vanadium-gallium and vanadium-aluminum reached 402.49 and 902.77, respectively. EDS analysis confirmed ion exchange between vanadium polyoxoanions and SO42- ions, while FTIR revealed that the resin's primary functional group is a tertiary amine, with new V-N peaks appearing after adsorption. XPS analysis indicated shifts in V2p binding energy, confirming vanadium uptake. The adsorption process, driven by intra-particle diffusion, was found to be endothermic and involved multilayer chemisorption with increased entropy.