THERMODYNAMICAL STUDY ON SOLVENT EXTRACTION OF METALS

Based on the solution theory,the thermodynamical approaches to calculation of the component activity coefficients in organic phases,to determination of the thermodynamical equilibrium constant of metal extraction reaction and to predic- tion of the metal extraction equilibrium distribution are presented.Three neutral solvent-metal extraction systems,TBP-UO_2Cl_2,TBP-UO_2(NO_3)_2 and (C_7H_(15))_2SO-UO_2 (NO_3)_2,have been tested solely by thermodynamical method.Seven models have also been examined and compared,Among them,the Scatchard-Hildebrand and Guggenheim ones are more simple and convenient for calculating practice.These two models have tried all available to both quarternary and ternary organic phases.