Study on the Enhancement of Oxidation and Leaching of Metal Elements in Vanadium-Bearing Minerals via Aerated Stirring
Converter vanadium slag and vanadium-containing spent catalysts are important secondary resources for vanadium extraction.However,during the leaching process,the oxidative leaching of vanadium is limited by mass transfer efficiency and gas diffusion coefficients,making it difficult to further improve the leaching rate.Therefore,achieving efficient oxidation of low-valence vanadium in vanadium-bearing mineral phases is critical for the sustainable production of vanadium.An aerated stirred reactor was used as the leaching device,the gas-liquid mixing distribution patterns during the stirring process were investigated through computational fluid dynamics(CFD)simulations,and the findings were applied to the liquid-phase oxidative leaching of vanadium and chromium from vanadium slag.The results show that aerated stirring facilitates uniform gas-liquid mixing and drives the gas-liquid mixture towards the bottom of the reactor,increasing gas residence time and subsequently enhancing oxidation efficiency.Through aerated stirring,the formation of high-density fine bubbles in the reactor improves the oxidation efficiency of metals,achieving an oxidation efficiency of over 98%for chromium in the vanadium slag.Further analysis of the leaching residues using electron paramagnetic resonance(EPR)reveales that aerated stirring directly promotes the oxidation and decomposition of solid-phase vanadium-chromium spinels,thereby improving subsequent leaching efficiency.This study,combining CFD simulations with experimental validation,provides a basis for using aerated stirring to enhance the oxidation and leaching efficiency of low-valence metals during liquid-phase oxidative leaching.It also offers valuable guidance for the design and operation of industrial stirred reactors.
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