Mn–Zn nano-crystalline ferrites synthesized from spent Zn–C batteries using novel gelatin method

Graphical abstract: It is clear that, the magnetic saturation value is closely related with the substitution of Zn2+ ions. It increases gradually with increasing Zn-substitution with an obvious decrease at x = 0.6. On the other hand, coercivity exhibited a reverse trend. Display Omitted Highlights: ► Mn–Zn ferrites were prepared using spent Zn–C batteries by using gelatin method. ► The ferrites were characterized using XRD, TEM, FT-IR and VSM measurements. ► Obtained magnetizations are significantly lower than that of bulk ferrites. ► The Zn-substitution was found to affect the structural and magnetic properties. -- Abstract: A novel recycling route using acid leaching, reduction and gelatin method was applied to recycle spent Zn–C batteries into more valuable magnetic nano-crystalline ferrites; Mn1−xZnxFe2O4 (with x = 0.2–0.8). The cost of this recycling technology has economical advantages, which holds promising industrial application products. Dried gel thermal decomposition process was monitored by simultaneous differential thermal analysis–thermogravimetry–differential scanning calorimetry. Phase composition, morphological and magnetic properties of the as-prepared precursors were characterized using X-ray powder diffraction, transmission electron microscopy, Fourier transform infrared and vibrating sample magnetometer. Single-phase agglomerated cubic ferrites with crystal sizes in the range 21–41 nm were detected. The obtained magnetization values are significantly lower than that of the bulk ferrite and showed a gradual increase with increasing Zn-substitution with an obvious decrease at x = 0.6. On the other hand, a reverse trend was exhibited by coercivity. The effect of Zn-substitution on both structural and magnetic properties, paved the way to suggest proper cation distributions for the investigated system