Formalism of dispersive kinetics is applied for the decomposition process of zinc leach residue in an inert atmosphere. Thermal decomposition has been studied in a tubular furnace under a constant nitrogen gas flowing, at four different operating temperatures. It was found that the presented dispersive kinetic model can much better describe the complex decomposition process than classic Sestak-Berggren kinetic model. It was shown, that increase in the values of dispersive parameter (H) leads to an increase in dispersion of conversion values, together with the appearance of the distribution of the apparent activation energies. It was established that several parallel elementary reactions with strictly defined, but different apparent activation energies, contribute to the overall decomposition process. The model presented in this article may offer a more physically meaningful approach for the treatment of the kinetic data for the investigated process, compared to that of standard (i.e., non-dispersive) kinetic model. (C) 2012 Elsevier B.V. All rights reserved.