Chair of Non-ferrous Metals and Gold, National University of Science and Technology “MISIS”, Moscow, Russia

P. V. Aleksandrov, Leading Engineer of a Center of Resourcesaving Technologies of Mineral Raw Materials Processing, Senior Researcher, e-mail: alexandrovpv@mail.ru
A. S. Medvedev, Professor
A. A. Kadirov, Candidate for a Master`s Degree

The perspective of chlorination roasting molybdenum concentrate with chlorides of alkalis metals arises from reduction of evolving of SO₂ in the atmosphere and formation of water-soluble compounds of molybdenum during roasting. It has been established that optimum temperature of roasting — 450 ^оC. It has been experimentally established that at chlorinating roasting of a molybdenum concentrate with sodium chloride about 30–33% of sulfur remains in a solid product of roasting in not sulphidic form. Thermodynamic feasible products of reaction between molybdenite and sodium chloride in the presence of oxygen at 450 ^оC have been determined. Solid products of interaction molybdenum concentrate with sodium chloride in the presence of oxygen as it experimentally has been established by X-ray diffraction analysis are Fe₂(MoO₄)₃, Na₆Mo₁₀O₃₃, and MoO₃. Gaseous molybdenum-containing products (molybdenum chlorides and oxychlorides) are experimentally has been established by mass-spectrometer measurements. It has been revealed, that 23–40% of molybdenum volatilized during roasting in form of MoO₂Cl₂, MoO₂Cl, MoCl₂ and MoCl₃. Maximum recovery of molybdenum from a solid sample remaining after roasting by alkaline leaching is about 100%, by ammoniac leaching is about 95% and by water leaching is about 64% (duration of roasting — 3 h, temperature — 85 ^оС, ratio solid : liquid = 1:8, [NaOH] = 100 g/l, С(NH₄OH) = 12.5%). The received results can to become a basis of a method of processing of the molybdenite raw materials excluding (or essentially reducing) evolving of dioxide of sulfur in the atmosphere.

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