KINETICS OF REAGENT OXIDATION OF MOLYBDENUM SULFIDE IN SULPHATE ELECTROLYTES

摘要

The sulphide phase of ore minerals is subject to passivation in oxidizing conditions. The kinetics of dissolution of polycrystalline sulfide minerals - the raw material of hydrometallurgy of molybdenum, copper, under conditions of variable hydrodynamics of interaction with the medium, is adequately described by the method of a rotating disk of dissolved material with a surface equally accessible to the diffusion of reagents. Overcoming the passivation of their surface is described by kinetic equations based on model representations. Objective: on the example of the behavior of Mo-concentrate in nitrate and hypochlorite electrolytes to describe the nature of the resulting products and the kinetics of their dissolution. Samples of Mo-concentrate (38 % Mo in M0S2 phase) were used. The concentration of Cu (II), Fe (III), Mo (VI), Re (VII) ions in solutions was determined photocolorimetrically and spectrometrically (AAS Perkin-Elmer 3030B, ICP- Aligent 7500 ICP MS); thermal analysis was carried out by dilatography, and microscopy of samples was carried out on scanning electron microscopes: SEM-EDS EVO-MA (Carl Zeiss Instrum) and JCM - 6000 Neoscope II (JEOL); spectral analysis - on a Nicolet iS50 FT-IR spectrophotometer (Thermo Scientific, USA), diffuse reflection electronic spectra - on a UV-2600 spectrophotometer (Shimadzu); structural and phase analysis - on an XRD Empyrean X-ray diffractometer (PANalytical), kinetic measurements were performed on powder samples of sulfide concentrates, t:W= 1:7 and 1:75. For example, oxidation of Mo-concentrate samples in a sulfate-hypochlorite electrolyte, during 1800 seconds, the destruction of the phase of Mo, Cu sulfide compounds was established, with the transformation of their share into the oxide-sulfate phase. The kinetics of oxidation of a number of minerals in a sulfate-hypochlorite electrolyte was studied in the temperature range 20-40-70 °C, at atmospheric pressure. The samples of the solid phase after their leaching were studied by the methods of thermal analysis, optical, UV and IR spectroscopy, X-ray diffraction, electron microscopy, and probe microanalysis of the surface areas of the grains.