Kinetic study of the thermal decomposition of low-grade nickeliferous laterite ores

Abstract

This study presents an evaluation of the decomposition kinetic of low-grade nickeliferous laterite by thermogravimetric analysis. Kinetic parameters were calculated using the Ozawa and the iso-conversional Friedman methods. Simplified kinetics models like those based on the reaction order were also applied for the simulations. Two-dimensional shrinkage models of the reaction interface mechanism were adopted as describing the thermal transformation process from non-isothermal kinetic analysis. The iso-conversional method (model-free kinetics) reveals that the decomposition of low-grade nickeliferous laterite does not follow a single mechanism because the determined activation energies and pre-exponential factor are not constant during the course of the reaction.