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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3 resultados
Resultados da Pesquisa
Item Flotation routes for a phosphate ore bearing silicate-carbonate gangue.(2012) Albuquerque, Rodrigo Oscar de; Peres, Antônio Eduardo Clark; Aquino, José Aury de; Pereira, Carlos AlbertoThis laboratory scale investigation addressed two different process routes for the concentration of a phosphate ore bearing a silicate-carbonate gangue: (i) bulk apatite and calcite flotation followed by calcite flotation in the presence of phosphoric and citric acids; (ii) calcite flotation in the presence of carbon dioxide followed by apatite flotation. The target of selectively separating apatite from the contaminating silicates and carbonates was achieved. Following the flotation experiments, calcite zeta potential determinations were performed aiming at clarifying the mechanisms that rule the adsorption of the soybean bran oil soap onto the mineral surface in the presence of the modifying agents phosphoric acid, citric acid, and carbon dioxide.Item Flotation concentration of a xenotime pre-concentrate.(1997) Pereira, Carlos Alberto; Peres, Antônio Eduardo ClarkThe worm market for rare-earths elements is increasing due to the development of new products and applications, resulting in the need for technology to treat deposits having highly complex mineralogy, such as that of Pitinga, AM, Brazil, with estimated reserves of 146,960 t of rare-earths oxides (REO), including Y203. Mineralogically the mine of Pitinga is very rich. The initial and major target of the company Paranapanema was the production of tin concentrates from placer deposits and later from primary ore. However, geological studies identified several other minerals of potential economical importance, such as: columbite-tantalite, zircon, cryolite and xenotime, the objective of the present investigation. The response of a pre-concentrate sample of the non-conducting fraction from Pitinga " s electrostatic separator to laboratory scale physical concentration methods was very poor. Another possibility for the selective separation of xenotime and zircon (the major associated mineral) is flotation. Microflotation experiments were performed in a modified HaUimond tube with pure samples of xenotime and zircon, in the presence of hydroxamate as collector and five different reagents as depressants.Item Dispersion effect on a lead–zinc sulphide ore flotation.(2009) Silvestre, Marcelo Oliveira; Pereira, Carlos Alberto; Galery, Roberto; Peres, Antônio Eduardo ClarkThis investigation was performed with samples from a lead–zinc sulphide deposit aiming at studying the influence of the dispersion degree of the particles in the pulp on lead and zinc flotation. Samples of ore and also of the minerals sphalerite, galena, pyrite, and dolomite were selected for the experiments. Nine types of dispersing agents and six blends among them were employed. A set of three dispersing agents was selected for the lead flotation and another set of three was chosen for zinc flotation. The criteria for the reagents selection were: high dispersion degree for galena and low for the other species, high dispersion degree for sphalerite and low for the other species, low dispersion degree for pyrite and high for the other species, and high dispersion degree for all species. Lead flotation experiments were performed under three conditions aiming at verifying the influence of the dispersing agent, of the pH, and of sodium carbonate. The zinc flotation tests were carried out at pH 10.5, modulated with lime. The use of dispersing agents in lead flotation did not improve the overall efficiency of the circuit for, despite improving the lead metallurgical recovery, they increase significantly the zinc losses in the lead concentrate. Sodium carbonate presented a low dispersion degree and did not affect the lead flotation results when compared with those achieved at natural pH and at pH 9.8 modulated with lime. Two dispersing agents were particularly effective in zinc flotation: dispersant 3223, a sodium polyac-rylate, and sodium hexametaphosphate. Both reagents significantly enhanced zinc recovery without impairing the concentrate quality.