The optimal kinetic models for the conversion of metastudtite-to-uranium trioxide nuclear materials by using the thermogravimetric analysis
摘要
The kinetic analysis for the conversion of metastudtite (UO4·2H2O)-to-uranium trioxide (UO3) nuclear materials, namely the optimal kinetic models to describe the process, has been studied. By using various isoconversional models, including Flynn–Wall–Ozawa and Kissinger–Akahira–Sunose, and based on thermogravimetric analysis (TGA) data of metastudtite at different heating rates of 10, 15, 20, and 30 °C min−1, the activation energies E for the conversion of the metastudtite-to-UO3 nuclear materials at a given conversion coefficient α were determined. The activation energy was then used for calculating the pre-exponential factor A in the Arrhenius equation. The optimal kinetic models to describe the conversion of the metastudtite-to-UO3 nuclear materials at different heating rates were established by combining the function f(α), which describes the process, with the activation energy data and the pre-exponential factor A. The studies on the optimal kinetic model provided a better understanding for the conversion of the metastudtite-to-UO3 nuclear materials, enabling better control over this process.