Preparation of U₃O₈ by calcination from ammonium uranyl carbonate in microwave fields: Process optimization

Highlights: • The U₃O₈ was prepared first from ammonium uranyl carbonate using microwave. • A quadratic model was developed to optimize the process conditions. - Abstract: The effects of process conditions on preparation of U₃O₈ by calcination from ammonium uranyl carbonate in microwave fields were assessed and optimized for maximizing the total uranium as well as calcination temperature, adopting as Central Composite Design (CCD) methodology. The process variables assessed were calcination temperature, calcination duration and mass of sample. A quadratic model relating the process variables and the total amount of uranium and U₃O₈ was proposed eliminating the insignificant parameters. The optimal calcination conditions were estimated to be a calcination temperature of 942.75 K, calcination duration of 8.78 min, with the corresponding total uranium and U₃O₈ to be 82.07% and 31.33%, respectively