| 摘要 |
A method for converting UO3 and/or U3O8 into hydrated UO4 of formula UO4.nH2O wherein n is 2 or 4, comprising the following successive steps: a) preparing an aqueous suspension of a UO3 powder and/or a U3O8 powder; b) adding hydrogen peroxide H2O2 to the aqueous suspension of a UO3 and/or U3O8 powder, converting the UO3 and/or U3O8 into hydrated UO4 and precipitating, crystallizing the hydrated UO4 in the suspension; c) recovering the precipitate, crystals of UO4 hydrate; d) optionally, washing the recovered UO4 hydrate precipitate, crystal(s); e) optionally, repeating step d); f) optionally, drying the precipitate, the crystals; wherein the addition of H2O2 to the aqueous suspension is carried out so that the suspension contains a stoichiometric excess of H2O2 relatively to the stoichiometry of the reaction from UO3: UO3+nH2O+H2O2→UO4.nH2O+H2O  (1) or of the reaction from U3O8 UO2.67+1.33H2O2+nH2O→UO4.nH2O+1.33H2O  (2), and the pH of the suspension is maintained in steps a) and b) at a value comprised between 2 and 3. |
