Refining of low-grade molybdenite concentrate

Abstract

Nearly 50% of molybdenum production is derived from the beneficiation of coppermolybdenum porphyries and other polymetallic molybdenum ores. Such by-product concentrates are of low-grade with substantial quantity of impurities and are not amenable for the extraction of molybdenum by traditional practices. Moreover, presence of impurities, particularly copper, drastically reduces the market value of the molybdenite concentrate. Treatment of low-grade concentrates for molybdenum production involves large number of complex processing steps with low recovery. Alternatively, the impurities including copper may be removed by selective dis-solution resulting in refining of molybdenite concentrate which may be used as a high-grade concentrate for the production of molybdenum. Literature survey indicates that over the past five decades, significant research efforts have been made in this direction by using appropriate lixiviants such as ferric and cupric chlorides, hot concentrated sulfuric acid, sodium cyanide and a combination of hydrofluoric and hydrochloric acids. Recently bioleaching has also been used for selective dissolution of metal sulfides, particularly chalcopyrite. In this chapter, various methods applied for the refining / purification / upgradation of low-grade molybdenite concentrates by selective dissolution of impurities are briefly discussed. © 2014 by Nova Science Publishers, Inc. All rights reserved.