The optimization of Cu and Fe bioleaching from converter slag using Acidithiobacilus ferrooxidans

The main objective of this work was to assess the optimization of Fe and Cu bioleaching from converter slag using Acidithiobacillus ferrooxidans. Important parameters that contribute to the bioleaching process include initial pH, initial Fe2+ concentration and pulp density. In order to optimize these parameters, the response surface methodology (RSM) was applied. The maximum simultaneous Fe and Cu recovery yields were 95% and 100%, respectively. The optimum conditions were initial pH 1.8, initial density 1.4 g/100 mL and initial Fe2+ 7.3 g/L. The comparison between chemical leaching and bioleaching results showed that bioleaching improved the recovery yields of Fe and Cu by 26% and 33%, respectively. The modified shrinking core model was used to determine the rate-limiting step of the process. It was found that diffusion through the product layer and chemical reaction are the rate controlling steps.