TRIALKYL (C_6-C_8) PHOSPHINE OXIDE FOR THE EXTRACTION OF ACTINIDES AND LANTHANIDES FROM HIGH ACTIVE WASTE

The extraction behavior of trialkylphosphine oxide (TRPO) for HAW constituents and factors (nitric acid and TRPO concentration, temperature, salting agent, diluent etc.) influencing extraction are studied. Distribution ratios of HAW constituents between 30% (vol.) TRPO-kerosene and aqueous nitric acid are determined. The solvation number and apparent equilibrium constants of certain ions in TRPO extraction are given. Results show that TRPO is a good extractant for the extraction of actinides and lanthanides from acidic HAW.