Journal of Nuclear Fuel Cycle and Waste Technology

The solubility of U(VI) hydrolysis products was determined by using a laser-induced breakdown detection (LIBD) technique. The experiments were carried out at uranium concentrations in range from 2×10-4 M to 4×10-6 M, pH values between 3.8 and 7.0, the constant ionic strength of 0.1 M NaClO4 and the temperature of 25.0±0.1℃. The solubility product of U(VI) hydrolysis products was calculated from LIBD results by using the hydrolysis constants selected in NEA-TDB. The solubility product extrapolated to zero ionic strength, logK°sp=-22.85±0.23 was calculated by using a specific ion interaction theory (SIT). The spectral features of ionic species in uranium solutions were investigated by using a conventional UV-visible absorption spectrophotometer and a fluorophotometer, respectively. (UO2)2(OH)22+ and (UO2)3(OH)5+ were dominant species at uranium concentration of 2×10-4 M.

Keywords

Uranium(VI),Solubility,LIBD,Hydrolysis,Speciation,Spectroscopy