METHODS OF DESCRIBING ASSOCIATION DURING EXTRACTION OF INORGANIC-COMPOUNDS

Solutions of the principal classes of extractants, neutral (TBP), acid ic (DEHP), and basic (tertiary amines), in benzene and cyclohexane pro vide examples for examining methods of estimating the parameters that characterize the nonideality of the systems, activity coefficients gam ma(A) and association constants K(i)', using experimental data for the solvent activity. Seven approximations are proposed for integrating t he Gibbs-Duhem equation in the analytical form. A method is developed for calculating association constants within the framework of a model for an ideal associated solution. It is based on expansion of the appr oximations in a Maclaurin series. Osmometric measurements are used to calculate gamma(A) and K(i)' in the studied systems.