Mössbauer Spectroscopy and SEM Characterisation of Commercial Ferrosilicon Powders

Ferrosilicon is used as a medium for separating different minerals in beneficiation, and is recovered by magnetic separation, then recycled. Commercial grades exhibit different magnetic properties and a range of chemical compositions, and the former can lead to non-recovery and cost implications. A study was carried out on samples of commercial ferrosilicon in an attempt to characterise the varying saturation magnetism (Satmagan) value. The samples had Satmagan values between 56 and 68% (as measured against a ferrite standard). Mössbauer results showed that peaks became more pronounced with increased Satmagan value. This indicates that the order of the Fe₃Si DO₃ phase increased with higher Satmagan value. Scanning electron microscopy revealed that the microstructure comprised dendrites (with 30–34 at. % Si) which were surrounded by a eutectic comprising 22–31 at. % Si, with the dendrites being the major phase.