Recovery of Vanadium as Iron Vanadate (FeVO₄) from Spent Sulfuric Acid Catalysts Using Oxalic Acid Leaching

Department of Chemistry, Coordination and Analytical Chemistry Laboratory (LCCA), Faculty of Sciences, Chouaïb Doukkali University, El Jadida, 24000, Morocco.

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Abstract

Used sulfuric acid catalysts are a hazardous industrial waste and also a secondary resource enriched with valuable transition metals such as iron (Fe) and vanadium (V), which can be recycled. Improper disposal poses a severe impact on environmental pollution, while the material can easily be recycled for producing next-generation materials. This study deals with valorization and selective recovery of iron vanadate (FeVO₄) from a used sulfuric acid catalyst. This study proposed a hydrometallurgical method to recycle the vanadium component in used sulfuric acid catalysts, which involves the treatment with a 0.5 mol. L⁻¹ oxalic acid solution under optimised conditions, such as a solid-liquid (S/L) ratio of 1:25 (g/mL), a temperature of 80°C, and stirring speed of 300 rpm. This procedure helps in the creation of a crystalline FeVO4 material, which has been detected through X-ray diffraction (XRD) analysis, with a resultant recovery yield of approximately 20% vanadium. This synthesized material possesses a similar material structure to that which can be obtained from laboratory pure materials. This study, therefore, not only finds applications in producing FeVO4 materials, which will have potential uses in the production of steel, batteries, and photocatalysis, etc., but also helps in recycling industrial waste material.