The deactivation model was used to explain kinetics underlying the conversion reaction of trona to NaHCO 3 (sodium bicarbonate). The model showed good agreement with the experimental data obtained from the conversion reaction of trona to NaHCO 3 . It gave the value of 0.94 as an average correlation coefficient with the experimental data. However, at lower temperature, the model was in poor agreement with the data. This would be related to the structural variation of trona particles at the lower temperature. A trona particle is initially nonporous and then it begins to crack. This structural variation creates more surface area for the reaction with CO 2 and water vapor. However, at the lower temperature, the fissures on the surface of the particles are not fully developed during the beginning of the reaction. As a consequence, the level of the conversion of trona at the lower temperature is low during the beginning of the reaction and the time to approach the complete conversion is shorter as temperature increases. However, since the deactivation model does not include the term articulating the degree of the structural variation during the reaction, it does not fit well to the experimental data at the lower temperature. The deactivation rate constant, k d is strongly temperature dependent and the change of the slope suggests the reaction mechanism changes as the reaction temperature increases.