Vanadium recovery from solid catalysts by means of Thiobacilli action

Bioleaching of Vanadium-Titanium and spent Vanadium-Phosphorous catalysts w ith Thiobacillus thiooxidans cultures and elemental sulphur as energy sourc e, allowed up to 98.4% vanadium recovery. Thiobacillus thiooxidans catalyse s the aerobic oxidation of elemental sulphur which generates sulphuric acid and reducing intermediate species. These substances reduce and dissolve va nadium species that are present in the catalysts under oxidation state (+5) . The amount of recovered vanadium was correlated with the catalysts reduci bility.