Magnetic properties of magnetite-based nano-glass-ceramics obtained from a Fe-rich scale and borosilicate glass wastes

Abstract

Magnetite-based glass-ceramic is a special composite material composed by magnetic nanocrystals embedded in a vitreous matrix. In this work, it was developed magnetic glass-ceramics based on borosilicate glass wastes and, for the first time, by using iron-rich scale (a waste from the metallurgical industry). Different compositions were established with increasing scale contents (20, 30, 45 wt%). Raw materials were melted (1550 °C/4 h) and later cast in a preheated steel mold at 400 °C. Then, the obtained samples were heat-treated at 700 °C/ 30 min. The sample with 45 wt% scale also was heated at 800 °C and 900 °C/ 30 min, in order to promote more crystallization. The obtained glass-ceramics properties were investigated using X-ray diffraction (XRD), Raman spectroscopy, vibrating-sample magnetometer (VSM), Mössbauer spectroscopy and transmission electron microscopy (TEM). Magnetite nanocrystals (average size in the 40–64 nm range) in the glass-ceramics were evidenced by TEM images and Mössbauer spectrum. VSM analysis revealed that the obtained ferrimagnetic glass–ceramic with composition of 45 wt% scale annealed at 800 °C/ 30 min, improved the magnetic saturation (Ms), reaching 42 emu/g. Results indicated a great potential of this magnetic-based glass-ceramics for being applied in many applications, such as the biomedical engineering field, in magnetic devices, magnetic resonance imaging contrast agents, hyperthermia, waste sorbent, and microwave devices.