Characterization of Spent Household Zinc-Carbon Dry Cell Batteries in the Process of Recovery of Value Metals

Abstract

Spent zinc-carbon dry cell batteries were characterized to assess the environmental impacts and also, to identify the potentials of recovering the metal values from these batteries. Different component parts of both new and spent batteries of all the five types (AAA, AA, C, D and 9V) were examined. The outer steel casings were found to be tin plated. Steel, zinc and manganese constituted 63 percent of the total weight of the battery. Average zinc and manganese contents were about 22 and 24 percent of the total weight of spent batteries. The electrolyte paste of the spent batteries contained 22 wt. percent zinc and 60 wt. percent manganese. The rest was chlorine, carbon and small amounts of iron and other impurity elements. The major phases in the fresh batteries were carbon, MnO2 and NH4Cl, while Zn(NH3)2Cl2, ZnO.Mn2O3, Mn3O2 and Mn2O4 were the prominent phases in the spent batteries. Presence of mercury and cadmium were not detected and a small percentage of lead was found in both the zinc anode and in the electrolyte paste.