Thermal decomposition kinetics of ammonium uranyl carbonate

Uranyl ammonium carbonate precipitation and conversion into triuranium octaoxide

“…By analyzing this mass variation, the material balance calculations unequivocally indicated that the AUC compound was (NH 4 ) 4 UO 2 (CO 3 ) 3 . Consequently, our study successfully identified the conditions conducive to the formation of AUC precipitates, which are very similar to the findings reported in the literature [ [37] , [38] , [39] , [40] , [41] , [42] ]. Therefore, to achieve the precipitation of free AUF, a C/U molar ratio greater than six is required.…”

“…8 . The typical dTG and TG curves of the AUC decomposition reaction obtained under these conditions are similar to those described in the literature [ [37] , [38] , [39] , [40] , [41] , [42] ]. The dTG and TG curves obtained during AUC decomposition ( Fig.…”

“…The decomposition reaction involves the formation of intermediate compounds, specifically, UO 3 . When AUC is treated in air, the final product is U 3 O 8 , as reported previously [ [37] , [38] , [39] , [40] , [41] , [42] ].…”

“…The decomposition reaction of AUC in air is summarized as follows (Eq. (19) ) [ [37] , [38] , [39] , [40] , [41] , [42] ]: (NH 4 ) 4 UO 2 (CO 3 ) 3 = UO 3 + 4NH 3 + 3CO 2 + 2H 2 O …”

“…Numerous previous studies [ [37] , [38] , [39] , [40] , [41] , [42] ] explored the decomposition of AUC in different environments, such as O 2 , Ar, N 2 , and 90% Ar–10% H 2 mixtures. Our TG–dTG curves obtained at a heating rate of 10 °Cmin -1 in oxygen and inert gases (argon and nitrogen) were similar to those reported in the literature.…”