Study of Oxidation-Reduction Potential in Uranium Bioleaching from a Low Grade Ore

Oxidation-reduction potential (ORP) in uranium bioleaching from a low grade ore by Acidithiobacillus ferrooxidans is measured experimentally under different conditions. The experimental results are fitted to the mixed potential model, obtained from Butler-Volmer equation. The results from this fitting showed that the model predictes the ORP in uranium bioleaching from 1th anomaly of Saghand ore with very high accuracy the relative error of the present applied model in the process of the used ore is less than 4%. The average values of the electrochemical rates constants km/kα, kc/kα and b related to the experiments with the pulp density of 5% and 10% (w/v) were obtained to be 260, 30606 and 0.01 respectively. The experimental results were also compared with the Nernst equation prediction for two cases of γi=1, γi≠1. The results showed that the relative error of this model is less than 45% with activity coefficients equal to one and less than 35% with real activity coefficients.