Study on the thermodynamic properties of nickel-cobalt ore bio-leaching solution

Researches about the separation process of valuable metals for nickel-cobalt ore bio-leaching solution had already been continuously studied, while studies about its thermodynamic properties has not been carries out. This paper conducted research about thermodynamic properties including conductivity, activity coefficient of nickel-cobalt ore bio-leaching solution. Conductivity of nickel and cobalt in bio-leaching solution system was determined with conductivity method at a temperature range from 298K to 313K. The mean activity coefficient of nickel-cobalt in bioleaching solution was calculated with relative formula, and effect of the temperature and the concentration to the mean activity coefficient have been discussed. The comparison of thermodynamic properties has been researched in presence of bacteria and aseptic condition. To reflect the solution components' effect on its thermodynamic state, this paper used the Meissner-Pitzer Model to analyze the variation rule of the activity coefficient, and quantified change of thermodynamic properties of the system when the pH value and ion concentration changed.