Thermal Decomposition of Ammonium Uranate; X-Ray Study

Optical Absorption Edge of Ammonium Uranate and Uranium Oxides: Part II

“…These in tum can only affect the structure by minor distortion and shrinkage of one lattice. This is also confirmed previously by X-ray diffraction studies [12].…”

“…This was done on the AU and samples calcined at 350, 500, 750, 850°C [5,11,12]. The samples were also thermally analyzed [5,10,11 ].…”

“…The samples were also thermally analyzed [5,10,11 ]. The chemical analysis [12] was done for sample A as a representative one for the presence of NH4 ion. The NHJ /U ratio was found to be 0.634 for the unwashed sample and 0.529 for the washed one.…”

“…This may be clarified by returning to the thermal and X-ray diffraction analysis of the corresponding samples which proved that at SSO'C the ammonia is still retained [10]. The Xray analysis proved that the impurities in the unwashed samples when calcined at 500 °C hindered the formation ofpureß-U03 [11,12,18]. The value 2.175 eV corresponding to Eg of ß-UOs [13] is obtained in case of samples A and C after being washed and calcined at 500°C.…”

The Impact of Ammonium and Nitrate Impurities on the Formation of Uranium Oxides, in the Composition Range UO3-U3O8-z, during Thermal Decomposition of Ammonium Uranates

“…Fodor et al [7], and Ball et al [8] stated that washing of ammonium uranates (AU) before thermal decomposition leads to /?-U0 3 , while Daharwadkar et al [9] mentioned that the washed AU give amorphous uranium trioxide (A-U0 3 ). El-Fekey [10] stated that washing AU, precipitated at pH 8, resulted in the formation of ß-\J0 3 .…”