Characterization of size- and shape-controlled magnetic iron oxide microspheres fabricated by the flame method from industrial steel waste

Abstract Magnetic microspheres were fabricated from industrial waste via a single-stage flame spheroidization method using two ferric oxide precursor powders from steel hot rolling industry. The analysis of all samples was carried out by scanning electron microscopy (SEM), X-ray diffraction (XRD), Mössbauer spectroscopy, FTIR and Raman spectroscopy (RS), thermogravimetric analysis (TGA), and vibrating sample magnetometer (VSM). SEM, XRD, Mössbauer spectroscopy, FTIR and RS show the morphology, structure, and phases of the samples studied. The average size for each microsphere was 45 μm (Sample A2) and 60 μm (Sample B2). TGA confirmed the crystallization and phase transition of iron oxides. The VSM study showed high saturation magnetization ( M s ) for both microsphere samples, with the higher M s being very close to the reported value for bulk magnetite and exhibiting a very soft magnetic behavior. The flame spheroidization processing route provides a method for producing microspheres with high uniformity and size control. These factors make the method promising for biomedical, environmental remediation, and energy device applications.