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RESUMOO crescimento da produção e do valor do minério de ferro frente a aumentos de demanda tem levado as mineradoras a buscar a ampliação de suas reservas a partir de recursos minerais de baixo teor. O intemperismo atuante sobre eles resulta em composições mineralógicas e aspectos de associação mineral diversa, especialmente em relação aos conteúdos de goethita e argilominerais, implicando na necessidade de estudos detalhados para avaliação da qualidade dos produtos passíveis de serem obtidos, quanto a teores de SiO2, Al2O3, P e perda ao fogo, críticos nas especificações metalúrgicas. Neste contexto, duas amostras com diferentes graus de intemperismo e composição mineralógica foram estudadas, visando avaliar a possibilidade de obtenção de produtos dentro das especificações usuais requeridas. Os estudos compreenderam cominuição em duas condições: separações minerais e avaliação dos aspectos mineralógicos por análise de imagens por feixe de elétrons (MLA). A amostra 1 é composta principalmente por hematita, quartzo e goethita e a amostra 2 por magnetita, quartzo e anfibólios. Os estudos mostram que, para uma recuperação de 95% do ferro contido nos óxidos de ferro, teoricamente, é possível obter-se produto com teor de 66% para a amostra 1 e 69% na amostra 2. PALAVRAS-CHAVE: minério de ferro, caracterização tecnológica, análise de imagens. ABSTRACTThe growth of production and the value of iron ore have led mining companies to seek expansion of its reserves from low-grade mineral resources, where the weathering process lead to varied mineralogy and mineralogical association, especially regarding the contents of goethite and clay minerals. Detailed characterization studies are fundamental to evaluate the products that can be obtained considering the grades of SiO 2 , Al 2 O 3 , P and loss on ignition, which are critical metallurgical specifications. In this context, this study is based on the characterization of two samples with different degrees of weathering and mineralogical composition to evaluate the possibility of obtaining granulometric products within usual specifications required. The main results were obtained from SEMbased image analysis (MLA). Sample 1 consists primarily of hematite, quartz and goethite, while sample 2 comprises magnetite, quartz and amphibole. Considering the Fe present in the iron oxides, the research indicates a potential recovery of 95 % with Fe grades of 66% for sample 1 and 69% for sample 2

The automated image analysis has an important role in the mineral industry due to the quickly analysis and the results reliability. The technique can be applied using images from a scanning electron microscope associated usually coupled with chemical microanalysis from an EDS system. These analyses are carried out in many stages of a mining project helping mineral exploration, mining (blending), mineral processing (mineral association), genetic studies and mineralization control.This technique allows a statistic analysis of a large numbers particles and data, providing information of mineralogical composition, mineral chemistry, elemental distribution, mineral associations, phase and spectra liberation and others.This study sets the applicability of automated image analysis of an iron ore sample with diverse preparation procedures and analysis routines, which were evaluated by the MLA system. An iron ore sample was chosen because it is a familiar and well-documented ore in the literature, that usually shows simple textures and mineralogy which makes easier the interpretation of results by a diversity of preparation procedures and analysis routines.Furthermore, the iron ore shows mineral phases with significant differences in specific gravity resulting in more difficulties in sampling and preparation procedures due to potential density segregation.

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