Chemical kinetic models, reaction mechanism estimation, and thermodynamic parameters for the non-isothermal decomposition of trona ore

Abstract

Trona ore, a naturally occurring sodium carbonate mineral, is a crucial raw material in various industrial applications, particularly soda ash production. Despite its significance, trona's thermal decomposition kinetics and underlying reaction mechanisms remain underexplored, limiting the optimization of industrial-scale processing methods. This study comprehensively investigates the non-isothermal thermal decomposition of trona using thermogravimetric analysis under different heating rates in an N₂ atmosphere. To determine the activation energy (Ea) and reaction mechanisms governing the decomposition process, FWO, KAS, Tang, Starink, and CR methods were applied. The results indicate that the thermal decomposition follows a nucleation-controlled reaction mechanism P₄ with activation energy values ranging from 122 to 131 kJ mol⁻¹, demonstrating that the process occurs through a single-step reaction. The thermodynamic analysis revealed that the decomposition process is endothermic, as indicated by the positive ΔH values, while the ΔS values suggest an increase in molecular randomness during decomposition. Additionally, ΔG calculations indicate that the reaction is non-spontaneous, necessitating external energy input. These findings provide critical insights into trona's kinetic and thermodynamic behavior, bridging the knowledge gap between experimental analysis and industrial processing applications. Unlike previous studies, this research comprehensively evaluates trona's decomposition behavior, offering valuable data for reactor design and process optimization.