PRECIPITATION KINETICS OF U(VI) PHASES FORMED IN HIGH CONCENTRATED SALINE SOLUTIONS

The purpose of this paper is to understand the influence of precipitat ion kinetics on the U(VI) phases solubility and therefore, on the crys tallinity of the phases formed. Precipitation kinetics was studied at constant pH value, by considering the influence of the method of pH co ntrol and oversaturation degree. Experiments were carried out at room temperature, anaerobic conditions and constant pH value. Characterizat ion of solid phases were performed by scanning microscopy and X-ray di ffraction. A comparison between particle size of the phase formed, sol ubility value obtained and precipitation method used was accomplished in order to develop a model for the U(VI) precipitation kinetics, in h igh concentrated saline solutions (5 M NaCl).