Solvent Extraction and Electrowinning (SX/EW) play an important role during the hydrometallurgical production of copper for low grade ores. To better understand the rapid Cu extraction/strip kinetics for producing a high-purity CuSO4-H2SO4 electrolyte and elucidate the method to maximize current efficiency by preventing leach carryover to electrolyte during SX and minimizing the iron concentration, a detailed speciation study is required to quantitatively describe the iron and copper distribution in the SX/EW solutions. In the present study, by virtue of our previous modeling work, thermodynamic modeling of the SX/EW solutions is carried out to quantify the distribution of iron (ferric and ferrous), copper and sulfuric acid. The developed model provides a mathematical tool capable of quantifying the concentrations of free ions and complexes in terms of temperature (25°C-60°C) and solution composition under simulated industrial conditions. Finally, oxidation reduction potential measurements are employed to validate the model.