Triuranium octoxide dissolution by nitric acid solutions with addition of ammonium nitrate

The processes of triuranium octoxide dissolution by nitric acid with and without addition of ammonium nitrate were investigated in the temperature range 75–95 °C and in the acid concentration range 3.0–14.36 mol/L. The optimal effect of nitrogen oxide reduction to elementary nitrogen was obtained by adding of ammonium nitrate in the concentration range 1–2 mol/L and at temperature 75 °C. The kinetics of triuranium octoxide dissolution by nitric acid solutions (3.0 mol/L) with and without addition of ammonium nitrate were studied. The highest dissolution rate was obtained at concentration of ammonium nitrate 2 mol/L and temperature 368 K. The source of ammonium nitrate in the technology of uranium refining can be ammonium polyuranate.

► The U3O8 dissolution in HNO3 with and without addition of NH4NO3 are investigated.
► Addition of NH4NO3 (1 - 2 mol/l) decreases the amount of NOX emitted by 50 - 90%.
► Addition of NH4NO3 (1 - 2 mol/l) decreases nitric acid consumption by 20 - 25%.
► The source of ammonium nitrate in uranium technology can be ammonium polyuranate.