Factors influencing bioleaching copper from waste printed circuit boards by Acidithiobacillus ferrooxidans

The aim of this paper is to understand the factors that influence copper leaching from electronic scrap. It is revealed that the bioleaching is greatly influenced by process variables such as Fe3+ concentration, quantity of stock culture added, and pH. Before starting the leaching process, A. ferrooxidans was cultivated for 3–4 days as stock culture, until the concentration of Fe3+ ions had reached about 7.00 g/L, which was considered strong enough to dissolve metallic copper. The results show that high leaching rates of copper could be achieved in the presence of 6.66 g/L of Fe3+, 100% addition quantities of stock culture, and pH 1.5. It is concluded that bioleaching copper from printed circuit boards (PCB) using Acidithiobacillus ferrooxidans (A. f.) is feasible.