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Lateritic ore is currently the main raw material that allows extraction of Ni by the Caron process. To date, the kinetic behaviour of the roasting/selective reduction process of lateritic nickeli-ferous ores on a pilot scale is largely unknown. In the present study, the kinetic behaviour, the controlling stage and the mechanisms that describe this process with the use of a mixture of 2 wt.% bituminous coal and 1.25 wt.% fuel oil as a reducing additive were determined during the evaluation of the high and low thermal profiles, respectively. The phases of the reduced/le-ached minerals and the fed ore were analysed by X-ray powder diffraction. It was observed that the mixture used as a reducing additive guarantees an adequate transformation in both thermal profiles; the relationship between the residual Ni and residence time is described by a first-order reaction with the determination coefficients greater than 0.949. Although the influence of post-combustion air is not analysed, the controlling stage was diffusion through the ash layer with an activation energy of 14.4060 kJ mol-1. Thus, the most precise combination to describe the process is diffusion through the ash layer and the growth of the nuclei.
