CARACTERIZAÇÃO QUANTITATIVA DE MINÉRIO DE FERRO POR MICROSCOPIA CO-LOCALIZADA

Despite progress in Scanning Electron Microscopy (SEM) automatic instruments, these systems are not capable of performing the identification and discrimination of major iron ore minerals (hematite and magnetite). On the other hand, Reflected Light Microscopy (RLM) can easily distinguish these iron oxides by their reflectancies, but it cannot discriminate quartz and epoxy resin, which presents similar color on images. Therefore, iron ore quantitative microstructural characterization is still a challenge. In the present work, a Co-Site Microscopy methodology that combines images obtained by RLM and SEM is applied to perform a quantitative characterization of an itabiritic iron ore. The so-called RLM-SEM Co-site Microscopy can discriminate phases that are not distinguishable with either RLM (epoxy resin and quartz) or SEM (hematite and magnetite) through this multimodal approach, allowing the subsequent mineralogical quantification. The applied methodology employs an automatic routine based on Image Analysis and Pattern Recognition techniques. The mineralogical quantification computed by image analysis was consistent with independently obtained results based on the Rietveld technique.