In this study, we present a model for the kinetics of multiple overlapping reactions. Mathematical representation of the kinetics of gas-evolving reactions is crucial for the modeling of the feed-to-glass conversion in a waste-glass melter. The model simulates multiple gas-evolving reactions that occur during heating of a high-alumina high-level waste melter feed. To obtain satisfactory kinetic parameters, we employed Kissinger's method combined with least-squares analysis. The nth-order reaction kinetics with variable reaction order sufficed for obtaining excellent agreement with measured thermogravimetric analysis data. (C) 2012 Elsevier B.V. All rights reserved.