from the conferences organized by TANGER Ltd.
In the production of molybdenum compounds, JSC "Almalyk MMC" (Republic of Uzbekistan), for a long time used the method of nitric acid opening of raw material, replaced by the scheme of ammonia, then soda leaching of the cinder of the industrial product of molybdenum after oxidative roasting. In view of the improvement of technologies and equipment, there is an interest in environmentally friendly hydro-oxidative methods for their processing based on a strong oxidizer. Molybdenum disulfide in the composition of molybdenite concentrate is subject to surface passivation under the oxidizing conditions of processing the cinder of an industrial molybdenum product. The use of a strong oxidizing agent, nitric acid, makes it possible to overcome it in the hydrometallurgical process of oxidative leaching. The purpose of the study: to study the kinetics of the reaction of oxidative leaching of molybdenite concentrate of industrial production of molybdenum in nitric acid solutions, with the regeneration of nitric acid in them. Used samples of molybdenite concentrate, composition, wt%: 38.0 Mo; 2.5 Cu; 13.8 Fe; 0.7 Re; 0.009 P; 0.025 Sb; 0.05 WO3; 25.2 S; 10.8 SiO2; 0.42 H2O; in solution, %: HNO3 0-25, H2SO4 5, O2. Kinetics of reagent oxidation of a sulfide mineral in nitric acid solutions, in the temperature range of 24-70 °C, at atmospheric pressure. was studied by the rotating disk method with control of the mass of the disk and the concentration of Cu(II), Fe(III), Mo(VI), Re(VII) ions in solutions. Kinetic measurements were performed on powder samples of Mo disulfide concentrate pressed into discs, 10 mm in diameter. Elemental analysis of samples was performed spectrometrically by methods of potentiometry, pH-metry, atomic absorption and optical emission (ICP-Agilent 7500 IСP MS), IR- (Nicolet iS50 FT-IR spectrophotometer, ThermoScientific), X-ray phase (XRD Empyrean X-ray diffractometer PANalytical).and X-ray fluorescence analysis (Rigaku NEXCGEDX RF Analyzer), scanning electron microscopy (SEM-EDS EVO-MA, Carl Zeiss Instrum). The parameters of the kinetic equation of the leaching process are obtained, the order of the reaction in terms of the concentration of the oxidizing agent, the activation energy of the process of solid-phase diffusion of molybdenum (VI) ions from the crystal lattice of the mineral into the liquid phase of the solution are calculated.
Keywords: Molybdenite concentrate, oxidation, nitric acid© This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.