Study and characterization of ammonium diuranate and uranium trioxide by thermogravimetry and differential scanning calorimetry
Description
Thermogravimetry (TG), Differential Thermogravimetry (DTG) and Differential Scanning Calorimetry (DSC) were used to characterize the thermal behavior of ammonium diuranate (ADU) and uranium trioxide (UO3) produced at IPEN'S Chemical Enginnering Department. Compounds characterization was done using the molar ratios among the compounds and the oxides resulting from thermal decomposition. The TG and DTG curves registered for each sample were used for the determination of the following temperatures: - temperature of water evolution (free and crystallized water); - ammonia evolution and oxidation temperature; - ocluded ammonium nitrate decomposition temperature and - oxygen release temperature. The intermediate phases and their thermal stabilities were also identified by TG and DTG and confirmed by DSC curves, DSC curves showed also the exothermic and endothermic behavior of the processes involved. Finally, the great amount of data collected in this study can be handed as a guide by the professionals responsible for the operation of ADU,UO3 and UF4 pilot plants. (Author)
Availability note (English)
Available from IPEN, Sao Paulo, Brazil.Abstract (Portuguese)
O comportamento termico de diuranatos de amonio e trioxido de uranio, produzidos no Departamento de Engenharia Quimica do Instituto de Pesquisas Energeticas e Nucleares, foi estudado por termogravimetria (TG), termogravimetria derivada (DTG) e calorimetria exploratoria diferencial (DSC). Os resultados inicias confirmaram os dados da literatura, constatando-se a influencia da variacao dos parametros de precipitacao e secagem sobre o comportamento termico deste compostos. A caracterizacao dos compostos foi realizada por meio das razoes molares entre seus constituintes e respectivos oxidos resultantes da termodecomposicao. A interpretacao das curvas TG e DTG permitiu identificar, para cada amostra, as temperaturas de eliminacao de agua (livre e de cristalizacao), evolucao e oxidacao de amonia, decomposicao do nitrato de amonio ocluido e perda de oxigenio, bem como as fases intermediarias e a estabilidade termica, fatos estes confirmados pelas curvas DSC. Os processos endotermico e exotermico correspondentes foram assinalados nas curvas DSC. Deste estudo resultou um numero consideravel de informacoes as quais poderao ser coordenadas e interpretadas para uso e orientacao nas operacoes das usinas piloto de obtencao de DUA, UO3 e UF4. (Autor)Additional details
Additional titles
- Original title (Portuguese)
- Estudo e caracterizacao de diuranato de amonio e trioxido de uranio por termogravimetria e calorimetria exploratoria diferencial
Publishing Information
- Imprint Pagination
- 227 p.
INIS
- Country of Publication
- Brazil
- Country of Input or Organization
- Brazil
- INIS RN
- 16033498
- Subject category
- S37: INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY;
- Resource subtype / Literary indicator
- Thesis, Non-conventional Literature
- Descriptors DEI
- ADU; CALORIMETRY; DECOMPOSITION; DIFFERENTIAL THERMAL ANALYSIS; QUANTITY RATIO; TEMPERATURE DEPENDENCE; THERMAL GRAVIMETRIC ANALYSIS; URANIUM TRIOXIDE
- Descriptors DEC
- ACTINIDE COMPOUNDS; AMMONIUM COMPOUNDS; AMMONIUM URANATES; CHALCOGENIDES; CHEMICAL ANALYSIS; CHEMICAL REACTIONS; DESTRUCTIVE ANALYSIS; GRAVIMETRIC ANALYSIS; OXIDES; OXYGEN COMPOUNDS; QUANTITATIVE CHEMICAL ANALYSIS; THERMAL ANALYSIS; URANATES; URANIUM COMPOUNDS; URANIUM OXIDES