Uranyl compound passing ADU, the manner null which transforms in UO2

摘要

PURPOSE: To directly obtain ADU(ammonium diuranate) in a particle form so that a fluoride-containing filtrate is not generated and a filtering operation is not required in transforming the ADU to the UO₂ by allowing gaseous ammo nia to react with a finely divided uranyl compound. ;CONSTITUTION: UO₂F₂ powder is produced by thermally hydrolyzing gaseous UF₆ with steam in a reactor. A satd. aq. soln. of the UO₂F₂ is formed by dissolving the powder to water. Metal oxide is added at need to the soln. so that a weight ratio of uranium to the total metal is ≥0.7. Wet ADU particles are produced by spraying the soln. to gaseous ammonia and/or a gas stream of an ammonium vapor having ≤10 atm a gas stream pressure at an operation temp. below 200°C while keeping the soln. below a boiling point. The particles are simultaneously dried and burned at ≤750°C and then, reduced to the UO₂ with gaseous hydrogen or a hydrogen-stream mixture at ≤850°C to obtain the fine powder having a low fluorine content and good sintering property.;COPYRIGHT: (C)1994,JPO