Oxygen solubility modeling in inorganic solutions: concentration, temperature and pressure effects

A model has been developed to predict and estimate the P_O2 and T-dependent molal solubility, (c_aq)_I, of oxygen in aqueous solutions containing an inorganic solute, I. It is based on the concept that (c_aq)_I may be obtained by multiplying the thermodynamics-based P_O2 and T-dependent equation for the molal solubility of oxygen in pure water, c_aq, by a factor (φ-factor) that is <1 and which is functionally dependent only upon the molal concentration, C_I, of I. The C_I-dependent φ-functions of 21 different I's have been determined from an analysis of published solubility data. Subsequently, the (c_aq)_I/P_O2 ratios for several solutions, containing single and multiple I, were predicted for a wide range of T by combining the corresponding φ-function with the thermodynamics-based equation for pure water. The predicted ratios were compared with available published data relating to effects of T. Satisfactory agreement was found between the predicted and experimental behavior, thereby validating the general principles of the model. It is anticipated that the model will be provide a foundation for predicting and estimating oxygen solubility under widely different hydrometallurgy leaching conditions, ranging from bio-leaching processes to oxygen pressure leaching.