Radium of radium Curie used the residues after extraction of uranium from pitchblende. The uranium had been extracted by dissolution in sulfuric acid leaving radium sulfate, which is similar to barium sulfate but even less soluble in the residues. The residues also contained rather substantial amounts of barium sulfate which thus acted as a carrier for the radium sulfate. The first steps of the radium extraction process involved boiling with sodium hydroxide followed by hydrochloric acid treatment to remove as much as possible of other compounds. The remaining residue was then treated with sodium carbonate to convert the barium sulfate into
Uranium nitride and, in particular, it undergoes an (n,p) reaction which produces significant amounts of radioactive C which would need to be carefully contained and sequestered during reprocessing or permanent storage. Each uranium dinitride complex is considered to have three distinct compounds present simultaneously because of decomposing of uranium dinitride (UN) into uranium sesquinitride (UN), and the uranium mononitride (UN). Uranium dinitrides decompose to uranium mononitride by the following sequence of reactions: Decomposition of UN is the most common method for isolating uranium sesquinitride (UN). Uranium mononitride is being considered as a potential fuel for generation IV reactors such as the Hyperion