From spent alkaline batteries to Zn Mn O by a hydrometallurgical route: synthesis and characterization.

A series of Zn/Mn binary oxides with different molar ratios (1.4-11) were synthesized co-precipitation from a solution obtained through the acidic (HCl) leaching of a black mass originating from the mechanical recycling of spent alkaline and Zn-C batteries. The oxides obtained were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. Magnetic properties of the samples were also investigated. The Raman spectroscopy results showed all the binary metallic oxides belong to the Zn Mn O (0.25 ≤ ≥ 1.75) type. All showed a spinel crystalline structure. The saturation magnetization decreases with the Zn/Mn molar ratio; a maximum of 13.19 emu g was found for the molar ratio of 11 at the Curie temperature (25.5 K). XPS showed that all the synthesized compounds contained Mn, Mn and Mn. Mn was the most prominent at a molar ratio of 11, Mn was most common at a molar ratio of 2, and Mn at 1.4.