Valorization of industrial iron and zinc sludges for the synthesis of ZnFe2O4 ceramics

The suitability of recycling some industrial wastes (zinc sludge, mill scale, and pellet fine) into valuable zinc ferrite ceramics via solid-state reaction has been investigated. Various properties of zinc ferrites prepared from pure oxides (as reference material) were compared with those prepared from mixtures containing or composed of wastes. The prepared ferrites were characterized using X-ray diffraction (XRD), Fourier-transform infrared characterized (FTIR), Field emission scanning electron microscopy (FESEM), Archimedes method, Vibrating sample magnetometer (VSM), and broadband dielectric spectroscopy (BDS). The results revealed that the highest density (5.05 gm/cm3), highest magnetization (4.8 emu/g), highest dielectric constant, and lowest resistivity (in the studies frequency range) were obtained for ferrite synthesized from pure oxides. However, ferrites synthesized from mixtures containing one waste exhibit physical and magnetic properties similar to those obtained for ferrites synthesized from pure oxides. The occurrences of cation redistribution for all synthesized ferrites confirmed by Rietveld analysis play a key role in the resulting properties. The properties of all synthesized ferrites from physical, chemical, magnetic, and electrical perspectives enable them to be a promising candidate in different electronic applications.