Determination of activity coefficients and relative partial molar free energies for copper sulfide mineral bioleaching solutions by ion-selective electrode

This work reports the results about the determination of mean activity coefficients and relative partial molar free energies for copper sulfide mineral bioleaching solutions by potentiometric method at 25 °C. The experimental potentiometric data were obtained by combining a diamond film—cupric ion-selective electrode (Cu(II) ISE), containing a KNO3 filling solution, and an Ag/AgCl electrode. The measurements were performed, at constant ionic strength, in different series of copper sulfide mineral bioleaching solutions. The non-ideal behavior of the system was described on the base of the Pitzer ion-interaction model for mixed salts. Meanwhile, the relative partial molar free energies of bioleaching solution were obtained. The determination of the thermodynamic properties offers a basic data for the study of copper sulfide mineral bioleaching solutions.