Reaction mechanism and kinetic analysis of citrate gel-combustion synthesis of nanocrystalline urania

The reaction mechanism and the determination of kinetic parameters of the citrate gel combustion synthesis of nanocrystalline urania (U 3 O 8 ) are being studied for the first time. The gel samples were subjected to simultaneous thermogravimetry–differential thermal analysis coupled with mass spectrometry to determine the reaction mechanism. The samples were also subjected to analysis by using differential scanning calorimeter to determine the kinetic parameters of the processes. It was observed that the combustion reaction took place in two steps followed by crystallization of uranium oxide to obtain nanocrystalline U 3 O 8 . The activation energy obtained (isoconversion method) for the first two steps of the reaction is 152 ± 6, 179 ± 7 kJ mol −1 , whereas activation energy for the crystallization of urania is 166 ± 7 kJ mol −1 (isoconversion method).