Tecnologia em Metalurgia, Materiais e Mineração
https://tecnologiammm.com.br/article/doi/10.4322/2176-1523.0979
Tecnologia em Metalurgia, Materiais e Mineração
Artigo Original

ANÁLISE MICROESTRUTURAL EM PASTILHAS PRENSADAS COM DIFERENTES TIPOS DE MINÉRIOS DE FERRO

MICROSTRUCTURAL ANALYSIS OF PRESSED SAMPLES WITH DIFFERENT TYPES OF IRON ORES (HEMATITIC, MAGNETITIC AND GOETHITIC)

Domingues, Alei Leite Alcantara; Brandão, Paulo Roberto G.

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Resumo

A produção de aglomerados de minério de ferro envolve a adição de materiais como calcário e cal para a formação de escória, que assume função importante na microestrutura do aglomerado envolvendo e sustentando as partículas de minério de ferro. Dessa forma, realizou-se um estudo comparativo das microestruturas formadas a partir de três minérios com características diferentes: hematítico, goethítico e magnetítico. Os minérios foram misturados à cal para obtenção de basicidade binária de 1,5% para todas as amostras. Em seguida, foram prensados e as pastilhas foram submetidas a aquecimento em forno irradiante que atingiu cerca de 1280 °C. As amostras foram então analisadas por microscopia de luz refletida com analisador de imagens e microscopia eletrônica de varredura. Foram observadas diferenças na quantidade de hematita, magnetita, silicatos e ferritas. A porosidade na pastilha hematítica foi menor, enquanto a pastilha magnetítica apresentou os maiores valores de porosidade total. A sustentação da matriz é feita por fases diferentes em cada caso e a composição química das ferritas mostra uma complexa variação composicional.

Palavras-chave

Microestrutura, SFCA, Aglomerados, Mineralogia, Minério de ferro.

Abstract

The production of iron ore agglomerates involves the addition of materials such as limestone and burnt lime to form slag, which plays an important role in the microstructure involving and sustaining the iron ore particles. Thus, a comparative study of microstructures formed from three ores with different characteristics: hematitic, magnetitic and goethitic, was carried out. The ores were mixed with burnt lime to obtain binary basicity of 1.5% for all samples. Then they were pressed and the samples were subjected to burnt in a rapid heat oven that has reached about 1280 °C. Then the samples were extensively analyzed by reflected light microscopy with digital images analyzer and scanning electron microscopy. Differences were observed in the amount of hematite, magnetite, silicates and ferrites. Porosity in the hematitic sample was lower, while the magnetitic sample had the highest total porosity values. The support matrix is made up by different phases in each case and the chemical composition of ferrites shows a complex compositional variation.

Keywords

Microstructure, SFCA, Iron ore agglomerates, Mineralogy, Iron ore.

Referências

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