Recycling spent zinc–carbon batteries through synthesizing nano-crystalline Mn–Zn ferrites

Abstract

In the present study, spent Zn–C dry batteries were used as a source of Zinc, manganese and iron for preparing manganese–zinc ferrites through citrate sol–gel auto-combustion method. The battery contents were leached with nitric acid and the chemical composition was estimated using atomic absorption spectroscopy (AAS). Stoichiometric amounts of the respective metal nitrates were used to adjust the proper compositions to reach Mn1−xZnxFe2O4 (with x=0.2–0.8). Thermal analysis measurements (DTA-TG-DSC) were carried out on the gel precursors to characterize the thermal decomposition reaction. X-ray diffraction (XRD) of as-prepared precursors showed single-phase cubic nano-crystalline ferrites. For different compositions, the lattice parameter, X-ray density and size were estimated and discussed. Fourier transform infrared spectroscopy (FT-IR) exhibited the characteristic absorption bands of ferrites and was used in cooperation with XRD to estimate the proper cation distribution of the systems. Transmission electron microscopy (TEM) was used to describe the morphology of the prepared ferrites and to estimate their sizes. The magnetic properties of the prepared ferrites were measured using vibrating sample magnetometer (VSM) and the different magnetic parameters were calculated and discussed. The effect of zinc substitution on the structural and magnetic properties of prepared ferrites was also estimated and discussed.