A one-dimensional model was built to simulate the non-steady radial combustion propagation on thin circular samples of Fe2O3/Aluminum thermite mixtures. The model considers zero order kinetics and conductive/radiative heat transfer. All the properties of the system are assumed to vary with the temperature and composition during the propagation and phase transitions are also contemplated. These features, not yet considered in the literature, allowed the obtainment of realistic solutions, readily comparable with experimental values measured in an earlier work. The experimental combustion velocities were used to adjust the kinetic constant of the model, in order to give it a good predictive capability. The predicted combustion temperatures and reaction extents were higher than the experimental. This was justified by the heat losses due to the spraying of products away from the combustion system and the incompleteness of the reaction, observed in experimental conditions and not considered in the model.