Molybdenite alkali fusion and leaching: reactions and mechanism

Abstract

The production of MoO₃ from Sarcheshmeh molybdenite concentrate via a pyro-hydrometallurgical process was studied. The molybdenite concentrate and sodium carbonate were premixed and fused under air atmosphere. Then the fused products were leached in water and the dissolved molybdenum was recovered as ammonium molybdate. The ammonium molybdate was then calcined to produce molybdic oxide. At the fusion stage, the effect of the mass ratio of carbonate to sulfide on the reaction products and the solubility of the products was investigated. The results show that during the fusion, sodium molybdate and sodium sulfate are the final reaction products and sodium sulfide is detected as an intermediate reaction product. By melting at 850°C with 5wt% excess carbonate, the maximum solubility of the products is obtained. The molybdenum is recovered from the solutions as ammonium molybdate.

Keywords

molybdenite / alkali fusion / leaching / sodium molybdate / molybdic oxide

References

[1] Gupta C.K. Extractive Metallurgy of Molybdenum, 1992 Boca Raton, CRC Press

[2] Gupta C.K., Mukherjee T.K. Hydrometallurgy in Extraction Process, 1990 Boca Raton, CRC Press

[3] Vizsolyi A., Peters E. Nitric acid leaching of molybdenite concentrates. Hydrometallurgy, 1980, 6(1–2): 103.

[4] Romano P., Blazquez M.L., Ballester A., et al. Reactivity of molybdenite concentrate against chemical or bacterial attack. Miner. Eng., 2001, 14(9): 987.

[5] Nair K.U., Sathiyamoorthy D., Bose D.K., Gupta C.K. Processing of low-grade Indian molybdenite concentrate by chlorination in a fluidised-bed reactor. Int. J. Miner. Process., 1988, 23(3–4): 171.

[6] Kar B.B., Murthy B.V.R., Misra V.N. Extraction of molybdenum from spent catalyst by salt-roasting. Int. J. Miner. Process., 2005, 76(3): 143.

[7] Singh S., Chetty M.K., Juneja J.M., et al. Studies on the processing of a low grade molybdenite concentrate by lime roasting. Miner. Eng., 1988, 1(4): 337.

[8] Prasad P.M., Mankhand T.R., Suryaprakashrao P., et al. Kinetics of the direct synthesis of molycarbide by reduction-carburization of molybdenite in the presence of lime. Metall. Mater. Trans. B, 2002, 33, 345.

[9] Othmer K. Encyclopedia of Chemical Technology, 1982 3rd Ed. New York, John Wily & Sons

[10] Charles F.B., Robert E.M. The Hydrolysis of Cations, 1980 New York, John Wily & Sons