Bioleaching waste printed circuit boards by Acidithiobacillus ferrooxidans and its kinetics aspect

In this paper, H+ consumption and metal recovery, during the process of bioleaching waste printed circuit boards (WPCBs) by Acidithiobacillus ferrooxidans (A. ferrooxidans), were discussed in detail. When the WPCBs concentration was 15 g/L, Cu (96.8%), Zn (83.8%), and Al (75.4%) were recovered after 72 h by A. ferrooxidans. Experimental results indicated that metal recovery rate was significantly influenced by acid. Based on experimental results, the kinetics of the H+ consumption and metal recovery on bioleaching WPCBs were represented by reaction kinetic equations. The kinetic of H+ consumption could be described by the second-order kinetic model. The metal recovery belongs to the second-order model with adding acid, which was changed to the shrinking core model with precipitate production.