PROCESS TO RECOVER MOLYBDENUM AND VANADIUM METALS FROM SPENT CATALYST BY ALKALINE LEACHING

摘要

There is provided a process to reclaim molybdenum, vanadium and other hydrodesulfurisation metals from catalysts, said process comprising collecting one or more catalysts containing at least one metal sulfide; leaching the catalyst in an atmospheric alkaline leach step; separating the leached slurry into a first liquid stream and a first solid; leaching the first solid in a caustic pressure leach process; separating the second leached slurry into a second liquid stream and a second solid; collecting the first and second liquid streams; oxidizing the combined liquid stream; cooling the oxidized liquid stream; adjusting the pH of the oxidized liquid stream; contacting the cooled oxidized liquid stream with an organic solvent containing an extractant; stripping the soluble metal species from the organic phase; adjusting the pH of the aqueous phase to selectively precipitate at least one metal as a metal salt; and separating the metal salt from the aqueous phase.