Thermodynamic study of the Cu-Na-H-SO4-Cl-HSO4-H2O system for the solubility of copper sulfate in acid seawater at different temperatures

Abstract The objective of the present work is the thermodynamic study of the Cu-Na-H-SO 4 -Cl-HSO 4 -H 2 O system using the Pitzer model in the temperature range from 293.15 to 333.15 K. Also, the water activities for aqueous solutions of copper sulfate were experimentally determined. This information and the Pitzer ion-interaction model were used to represent the solid-liquid equilibrium of the copper sulfate – sulfuric acid – seawater system. A simplification of the seawater system has been carried out, where the main ions from seawater (Na + and Cl − ) have been considered in the modelling. A good agreement between the correlated and the experimental solubility data of the CuSO 4 - H 2 SO 4 - seawater system was obtained, with an absolute average deviation of 0.0157 mol/kg. The ion-interaction model of Pitzer has been successfully used to predict the solubilities of an electrolyte in a system as complex as natural seawater, which makes it a suitable model to be applied to mining processes using seawater.