Solubility of uranium(IV) hydrous oxide in high pH solution under reducing condition

Abstract

Summary The solubility of uranium(IV) hydrous oxide was measured at 25 °C in NaClO 4 solution containing Na 2 S 2 O 4 as a reducing agent in the pH range from 12 to 14. The experiment was carried out from oversaturation at I = 0.5, 1.0 and 2.0 mol/dm 3 (M). The solubility data were analyzed to obtain the hydrolysis constants (β m ) of U(OH) m (4-m) . By taking the specific ion interaction theory (SIT) for ionic strength corrections and by using the solubility product log K sp ° = −53.93 ± 0.20, the hydrolysis constants at I = 0, log β 5 °<48.10 and log β 6 ° = 48.95 ± 1.01, were determined together with the ion interaction coefficients of U(OH) 5 − and U(OH) 6 2− .