Novel Clean Process for High-Purity Vanadium Production via Photocatalytic Chromium Removal
Biao Yuan, Kunpeng He, Pan Wu, Changjun Liu, Jian He, Wei Jiang
Abstract
The rapid growth of new energy technologies demands high-purity vanadium pentoxide (V 2 O 5 ) (≥99.95%), yet chromium entrapment during vanadium preparation remains a significant challenge. In this work, a novel photocatalytic chromium removal (PCR) process using P25 titanium dioxide and sodium thiosulfate pentahydrate to remove 99.5% chromium (residual chromium <0.1 mg/L) from vanadium solutions was proposed. The optimized conditions were as follows: 20 g/L V, pH 12–12.5, 25 g/L P25, 5 g/L Na 2 S 2 O 3 ·5H 2 O, and reaction time 2 h. The PCR process reduces Cr(VI) to Cr(III) and deposits as Cr 2 O 3 on the surface, while retaining dissolved V(V), confirmed by theoretical and characterization analyses. The process delivers V 2 O 5 with 99.99% purity after ammonium sulfate precipitation, and the vanadium yield was 89.27%. P25 titanium dioxide demonstrated excellent performance and stability with 95.5% chromium removal retention over ten cycles of PCR. Scale-up experiments further verified the potential for industrial application of this process. Regeneration and vanadium precipitation wastewater could be removed by adsorption using amorphous hydrous zirconium oxides (AHZOs) to achieve clean production. This work provides a novel and environmentally friendly production route for high-purity vanadium pentoxide.