Large-scale production of strontium ferrite by molten-salt-assisted coprecipitation

•Mass production of SrFe12O19 was achieved by molten-salt-assisted coprecipitation.•The mixture of NaOH and Na2CO3 was served as a precipitant during coprecipitation.•Effect of salt amount on morphology and magnetic properties of SrFe12O19 was studied.•A comparison of the products obtained on different preparation-scales was done.

Large-scale production of strontium hexaferrite (SrFe12O19) particles was successfully achieved by molten-salt-assisted coprecipitation. A mixture of sodium hydroxide and sodium carbonate was served as mixed precipitant to obtain ferrite precursors. The effects of the Fe3 +/Sr2 + molar ratio, calcination temperature, calcination time, and molten-salt amount on the formation, morphology and magnetic properties of SrFe12O19 particles were investigated. The resultant particles were characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, X-ray diffraction, scanning electron microscopy, and vibrating sample magnetometer. Single-phase SrFe12O19 particles, with particle sizes of 0.8–1.2 μm, were obtained from the precursor (with a Fe3 +/Sr2 + molar ratio of 10) being calcined at 950 °C for 2 h using the mass ratio (NaCl to precursor) of 0.3. The saturation magnetization, remanent magnetization and coercivity were about 62 emu/g, 37 emu/g, and 4310 Oe, respectively. A comparison of the products obtained at different preparation-scales was also done. The results showed that it was easier to control the particle morphology using molten salt synthesis and more economical on a large-scale production.

Graphical abstractParticle sizes were predominantly dependent on the NaCl amount and it was easier to control particle morphology using molten salt synthesis. The change of particles size further influenced the magnetic properties of SrFe12O19 particles.Figure optionsDownload full-size imageDownload as PowerPoint slide