Kinetic study of Mn and Zn dissolution from waste Zn-C batteries by shrinking core model

ABSTRACT The recovery of valuable metals from waste batteries gains more importance over time due to the decrease in natural resources and the possible harms of these to the environment. Economic benefits can also be obtained by recycling waste batteries. The recovery of valuable metals such as manganese (Mn) and zinc (Zn) in waste zinc-carbon (Zn-C) batteries has attracted the attention of many researchers. Hydrometallurgical methods are used as an effective method for the recovery of metals from waste Zn-C batteries. In this paper, kinetics of Mn and Zn dissolution from waste Zn-C batteries in sulfuric acid (H2SO4) solution was studied. The maximum Mn and Zn dissolution recoveries in 60 min leaching time were achieved using 400 rpm stirring speed, 0.25 M H2SO4 concentration, 70°C temperature and −53 µm particle size. In these conditions, Mn and Zn dissolution recoveries were obtained as 62.56% and 100%, respectively. To determine the dissolution kinetics of Mn and Zn, a new equation of shrinking core model was used and determined that Mn and Zn were dissolved in H2SO4 solution by interfacial mass transfer and diffusion across the product layer.