METHOD FOR CONVERTING UO3 AND/OR U3O8 INTO HYDRATED UO4

摘要

The invention relates to a method for converting UO3 and/or U3O8 into hydrated UO4 having the formula UO4, nH2O, where n is 2 or 4, including the following consecutive 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 UO3 and/or U3O8 powder, converting the UO3 and/or U3O8 into hydrated UO4, and precipitating and crystallizing the hydrated UO4 in the suspension; c) recovering the hydrated UO4 precipitate; d) optionally washing the hydrated UO4 precipitate; e) optionally repeating step d); and f) optionally drying the precipitate, wherein the addition of H2O2 to the aqueous suspension is carried out such that the suspension contains a stoichiometric excess of H2O2 with respect to the stoichiometry of the reaction from UO3: UO3 + nH2O + H2O2 ? UO4,nH2O+ H2O (1) or of the reaction from U3O8: UO2.67 + 1.33 H2O2 + nH2O ? UO4,nH2O+ H2O (2), and the pH of the suspension is maintained in steps a) and b) at a value between 2 and 4.