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The precipitation of Ni and Co mixes sulphides is one of the stages of the ammoniacal technological process in the cuban nickel industry, but the oxidation of sulphides disturbs its storage and transportation. This paper exposes results from chemical characterization by X-ray diffraction and mineragraphic analysis of mixed sulphides as well as from the kinetic investigation of the thermal oxidation of samples in isothermal and no isothermal regime. It's determined de most probable model and kinetic parameters of the physical-chemical transformations that occurs in oxidation process. It's concluded that oxidation of mixed sulphide concentrate follows 4 stages: lost of water and ammonio, degradation of superior sulphides, formation of sulphates and degradation of sulphates into oxides. Degradation of sulphides into oxides degradation of sulphides to oxides Nickel and cobalt sulphides obtained through leaching technology carbonates ammoniacal of laterític ferrous nickelitic ore is characterized and is studied in the kinetics of oxidation concentrated in nickel and cobalt sulphides applying the isothermic and not isothermic methods, being determined the most probable pattern and the kinetic parameters of the physical chemical transformations that take place in the process of oxidation. [ABSTRACT FROM AUTHOR]

The generalization of Barrett's method for the isothermal investigation of heterogeneous solid state reactions is proposed. This method allows calculation of the kinetic parameter (n) and determination of the appropriate kinetic model. The proposed method uses the f(a) function in its general form, for instance f(α) = αn, f(α) = (1- α)n, f(α) = (1-α)(-ln (1-α))1-1/n, and some others, unlike Barrett's method in which the function is restricted to f(α) = (1-α)n. [ABSTRACT FROM AUTHOR]