Microwave assisted dissolution efficiency of bioleaching of spent alkaline zinc manganese battery

In this study, Acidithiobacillus thiooxidans was used for bioleaching Zn/Mn in spent alkaline batteries electrode materials. The leaching efficiency of Zn and Mn among bioleaching, chemical extraction and microwave assisted bioleaching was studied. The results showed that both of the Zn and Mn leaching rates were reached about 49% in microwave assisted bioleaching after 9 days of bioleaching under the conditions of the concentration of elemental sulfur as the sole energy substrate of 20.0 g/L, the initial pH of 1.0, the culture temperature of 35℃ and the solid-liquid ratio of 1.0%. The extraction efficiency of microwave assisted bioleaching was much higher than the other leaching systems. Dissolution kinetics studies showed that the bioleaching behavior of Zn is best described by the chemical reaction controlled model but Mn had the different controlled model at the different leaching progress. In addition, SEM-EDS and XRD analysis showed that the ZnMn₂O₄ was broken down into MnO by using microwave irradiation, promoting the dissolution of Mn.