Types of goethite from Quadrilátero Ferrífero's iron ores and their implications in the sintering process

AbstractQuadrilatero Ferrifero's iron ores used in the sintering process correspond to mixes of hematitic and goethitic ore typologies. The ores have particle size mainly distributed in the range from 6·35 to 0·105 mm. The goethitic typology comprises a low amount in these ore blends; however, it can be relevant in the reactivity during sintering. This research involved techniques such as reflected light optical microscopy (RLOM) and scanning electron microscopy-backscattered electron (SEM-BSE) images for microstructure evaluation, and energy dispersive X-ray spectrometry (SEM-EDS) for microanalytical study. Many morphologies of goethite were identified considering the three ore blends: colloform type, massive, thin (granular and lamellae/fibrous) and earth-like. They have variable degrees of microporosity. Some microanalytical differences among these morphologies were observed as Si–Al–P bearing Gt, which corresponds to the common type, Al2O3-rich Gt and MnO bearing Gt. The latter two types have also Si,...