EM - Escola de Minas

URI permanente desta comunidadehttp://www.hml.repositorio.ufop.br/handle/123456789/6

Notícias

A Escola de Minas de Ouro Preto foi fundada pelo cientista Claude Henri Gorceix e inaugurada em 12 de outubro de 1876.

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Filtros

2013 - 20163

Configurações

Autor: search.filters.author.Peres, Antônio Eduardo ClarkAssunto: search.filters.subject.Hematite

Resultados da Pesquisa

Agora exibindo 1 - 3 de 3
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    Dispersion degree and zeta potential of hematite.
    (2016) Alexandrino, Júnia Soares; Peres, Antônio Eduardo Clark; Lopes, Gilmara Mendonça; Rodrigues, Otávia Martins Silva
    The dispersion degree of the mineral particles in the pulp is especially relevant regarding the performance of the cationic reverse flotation of iron ores. The gangue minerals should remain dispersed while hematite particles should be selectively flocculated. The present study addressed determinations of dispersion degree and zeta potential of hematite in the presence of different dispersants, classified as organic polymeric (natural and synthetic), organic monomeric, and inorganic. Special attention was paid to results achieved at pH 10, used in plant practice. For natural organic polymers, correlation was observed between the dispersion degree and the increase in the negative value of zeta potential. Some synthetic organic polymers enhance the dispersion of hematite particles despite not affecting significantly the zeta potential. Sodium silicates, irrespectively of the SiO2/Na2O ratio, at pH 10, did not impact significantly either the dispersion degree or the zeta potential.
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    Effects of hematite surface characteristics on filtration process.
    (2016) Graça, Leonardo Martins; Lagoeiro, Leonardo Evangelista; Galery, Roberto; Peres, Antônio Eduardo Clark
    In iron ore pelletizing plants a range of process parameters such as particle size distribution, specific surface area, and moisture, must be controlled to achieve opti¬mized operation conditions. Particle size distribution and specific surface area are con¬trolled during the grinding operations. Moisture, however, is controlled during filtra¬tion of the ground products. This work investigates the relationship between particle morphology, filter cake moisture and filter capacity. The samples were taken during the filtration tests and referred to three different blends presenting distinct mineralogical features and similar chemical compositions in order to investigate the effects of only the hematite surface characteristics. Six types of morphology are distinguished: granu¬lar hematite, tabular hematite, martitic hematite, polycrystalline hematite, hematite-goethite aggregates and goethite. For each filtration test, the filter cloth product was characterised. The characterisation analysis revealed that blends containing martitic hematite concentration above 11.45 percent increased substantially the filter capacity. However, it had also caused an increasing in final moisture content that reached values around 10.0 % compared with industrial moisture specification that can vary on the range of 8.5 to 9.5 %.
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    Kaolinite and hematite flotation separation using etheramine and ammonium quaternary salts.
    (2013) Rodrigues, Otávia Martins Silva; Peres, Antônio Eduardo Clark; Martins, Afonso Henriques; Pereira, Carlos Alberto
    Clay minerals are widespread in various types of mineral deposits. When present, they contribute to the high content of certain parameters such as silica, aluminium, and magnesium. This study aimed to find selectivity windows to separate hematite from a clay mineral (kaolinite) to allow reduction of the levels of silica and alumina in iron ore. The collectors used were: etheramine Flotigam EDA (EDA) and the ammonium quaternary salts: dodecyltrimethylammonium bromide (DTAB) and Tomamine Q-14-2 PG (AQ142). The depressant used was corn starch. The separation selectivity was achieved using DTAB in the pH range between 4 and 10. Using the collectors EDA and AQ142, the selectivity was obtained only in the presence of starch, at pH 10. Laboratory scale tests showed that as far as the particles size is concerned, better selectivity was achieved with finer particles. Circuit configurations including cleaner and scavenger stages, and pilot scale tests, will be required prior to a possible industrial implementation of the separation.