DEMIN - Departamento de Engenharia de Minas

URI permanente desta comunidadehttp://www.hml.repositorio.ufop.br/handle/123456789/510

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Autor: search.filters.author.Lima, Margarida Márcia FernandesAssunto: search.filters.subject.Sintering

Resultados da Pesquisa

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    Sintering of manganese ore tailings under an argon atmosphere.
    (2016) Lima, Margarida Márcia Fernandes; Valduga, Fillipe; Lima, Rosa Malena Fernandes
    Manganese is a chemical element widely used in Metallurgy. In Brazil, the ore’s beneficiation processes discharge the tailings (fraction size 0.106mm) with considerable Mn content. It would be interesting to recover this material. The aim of this work was to obtain and characterize the sinters from the manganese ore tailings at the Morro da Mina Mine. The fines (37 μm) were calcinated at 800°C for 3600s, and afterwards, homogenized with activated charcoal (7 and 10%) and CaO (5 and 10%). The sintering were carried out at 1135, 1140 and 1145°C during 7200 and 14400s under an argon atmosphere. The sintered products were characterized by BET surface area, apparent density, X-ray diffraction, MO and SEM/EDS. The presence of potassium from the alkalis justified the low melting point of the tailings (1145°C). Due to the chemical complexity of the tailings, several phases were identified in the products: pores, silicates with a high content of manganese in the matrix, as well as other silicates with different proportions of Al, Mn, Mg and Ca, pure Fe, and SiO2, etc.
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    Bench-scale calcination and sintering of a goethite iron ore sample.
    (2016) Silva, Mônica Suede Santos; Lima, Margarida Márcia Fernandes; Graça, Leonardo Martins; Lima, Rosa Malena Fernandes
    This work presents the results of bench calcination and sintering studies conducted on an iron ore sample from Iron Quadrangle, Brazil with high goethite content. The natural samples and the products of calcination and sinteringwere characterised by inductively coupled plasma optical emission spectroscopy (OES/ICP), X-ray spectrometry and gravimetric methods. Optical microscopy, X-ray diffraction (XRD) and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM/EDS) were used to identify the phases in the studied samples. Density, specific surface area, specific pore volume and pore diameter were determined through gas pycnometry. All of the natural sinter feed samples had a Fe grade N64% and a very high phosphorus grade (~0.17%). After calcination, a 3.1–3.4% increase was observed in the Fe grade compared to that of the natural sinter feed samples. The average Fe grade of the sintered samples was 59.1%. The identified phases with XRD in the raw materials were hematite and goethite. In the calcined samples, only hematite was identified because of the thermal decomposition of goethite. The density, specific surface area, specific pore volume and pore diameter of the calcined samples increased compared to those of the natural sinter feed samples. Hematite, brownmillerite, anorthite, and gehlenite were identified in the sintered samples. The sites for phosphorus occurrence were calcium silicates and apatite. The sintered samples exhibited specific surface areas lower than those of the calcined samples. This result was ascribed to the destruction of the pore structure by the sintering process.No relationship between the proportions of nucleate, intermediate and agglomerate particles used inmixture of sinter testswith the results of microtumbler was identified.