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.
http://dx.doi.org/10.4322/2176-1523.0979
Tecnol. Metal. Mater. Min., vol.13, n3, p.252-259, 2016
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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4 Wu S, Liu Y, Du J, Mi K, Lin H. Experiment Study of Assimilation Ability between iron ores and CaO. Journal of University of Science and Technology Beijing. 2002;24:258-261.
5 Wu S, Du J, Ma H, Zhang Z, Chen H. Fluidity of Liquid Phase in Iron Ores During Sintering. Journal of University of Science and Technology Beijing. 2005;27:291-293.
6 Scarlett NVY, Pownceby MI, Madsen IC, Christensen AN. Reaction sequences in the formation of silico-ferrites of calcium and aluminum in iron ore sinter. Metallurgical and Materials Transactions. B, Process Metallurgy and Materials Processing Science. 2004;35B(5):929-936. http://dx.doi.org/10.1007/s11663-004-0087-4.
7 Scarlett NVY, Pownceby MI, Madsen IC, Christensen AN. In situ X-ray diffraction analysis of iron ore sinter phases. Journal of Applied Crystallography. 2004;37(3):362-368. http://dx.doi.org/10.1107/S002188980400353X.
2 Ishikawa Y, Shimomura Y, Sasaki M, Hida Y, Toda H. Improvement of sinter quality based on mineralogical properties of ores. In: Ironmaking Conference Proceedings. Englewood: Iron & Steel Society of AIME; 1983. p. 17-29. vol. 42.
3 Dawson PR. Research studies on sintering and sinter quality: Part 2. Ironmaking & Steelmaking. 1993;20:137-149.
4 Wu S, Liu Y, Du J, Mi K, Lin H. Experiment Study of Assimilation Ability between iron ores and CaO. Journal of University of Science and Technology Beijing. 2002;24:258-261.
5 Wu S, Du J, Ma H, Zhang Z, Chen H. Fluidity of Liquid Phase in Iron Ores During Sintering. Journal of University of Science and Technology Beijing. 2005;27:291-293.
6 Scarlett NVY, Pownceby MI, Madsen IC, Christensen AN. Reaction sequences in the formation of silico-ferrites of calcium and aluminum in iron ore sinter. Metallurgical and Materials Transactions. B, Process Metallurgy and Materials Processing Science. 2004;35B(5):929-936. http://dx.doi.org/10.1007/s11663-004-0087-4.
7 Scarlett NVY, Pownceby MI, Madsen IC, Christensen AN. In situ X-ray diffraction analysis of iron ore sinter phases. Journal of Applied Crystallography. 2004;37(3):362-368. http://dx.doi.org/10.1107/S002188980400353X.
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