RECOVERY OF MOLYBDENUM FROM MOLYBDENUM BEARING SULFIDE MATERIALS BY BIOLEACHING IN THE PRESENCE OF IRON

摘要

The invention relates to a method of recovering molybdenum from a molybdenum bearing sulfide material. The material is contacted with a leaching solution in the presence of iron compounds and mesophilic or thermophilic iron oxidizing microorganisms and subsequently, a leaching process is performed by controlling the molar ratio of dissolved ferric iron to dissolved molybdenum. Preferably, a high amount and molar excess of dissolved iron is used. The presence of high concentrations of ferric iron in bioleach solutions allows iron-oxidizing microorganisms to grow and oxidize iron and bioleach molybdenite at dissolved Mo concentrations as high as 4.4 g/L. Organic metabolites were not required for protecting cells from Mo toxicity. Maximum dissolution rates depend on reactor configuration, with agglomerated material simulating heap leaching of almost 1% Mo/day, but up to 10.2% Mo/day in suspension/stirred reactor configurations, with rate highly dependent on temperature within the range of 25°C to 40°C. The ultimate extent of Mo removal from the molybdenum bearing sulfide material is 89%. Finally, molybdenum is recovered from a leach residue of the leaching process.