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This research is a proposal for replacing carbonated silt used as neutralizing agent in acid leaching technology with residual dust from marble industry. The liquor neutralization process in pressure acid leaching contains sulfuric acid concentration to excess with pH values equal to 1.9 units, which allows using solid calcium carbonate residues from marble industry. The research was carried out at laboratory scale with an agitation regime of 68 rpm. The multilevel factorial design was used, where two factors are studied: solid mass of neutralizing agent (1, 2, 3 and 4 g) and temperature (50 °C and 700 °C. Behavior of variables was also assessed by means of kinetic model. The statistical models showed a direct relationship between the increase of solid in the mass and the temperature, where the first factor exerts a positive influence on the process. The best pH results are obtained in test 1, for (50 °C and 1 g), where values from 2.37 to 2.53 are achieved between one to ten minutes. [ABSTRACT FROM AUTHOR]

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 objective of the study was to clean the kaolinitic clays in Cay Guam ore body through reverse acid leaching using chloride acid as a leach agent in order to clean the clay by eliminating the iron content. Techniques such as infrared and fluorescence spectrometry and X ray diffraction were applied during the characterization of the original raw material and after the reverse acid leaching process took place. The implementation of this method allowed extracting more than 98% of iron impurities, which resulted in obtaining a purer clay with silicon content of 60.48% and aluminum oxide of 49,50%. It was proved that the structure of the clay is not affected by reverse acid leaching and thus constitutes a method of beneficiation for kaolinites pigmented with iron. [ABSTRACT FROM AUTHOR]