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

2016 - 20202

Configurações

Assunto: search.filters.subject.Particle size distribution

Resultados da Pesquisa

Agora exibindo 1 - 2 de 2
  • Nenhuma Miniatura Disponível
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    Specific surface area of polydispersions as a function of size distribution sharpness.
    (2020) Lopes, Paulo Filipe Trindade; Luz, José Aurélio Medeiros da; Milhomem, Felipe de Orquiza
    Knowledge of particulate system properties is very important in various industrial instances and the possibility of fast predicting the behavior of such systems is an important control tool. The specifi c surface area of simulated particulate systems was studied as a function of the sharpness parameter of the size distribution of the Gates– Gaudin-Schumann, Gaudin–Meloy and Rosin–Rammler equations. The results showed good statistical adherence, especially the Rosin–Rammler equation, in situations where it is the best descriptor of particle size distribution.
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    Kinetics of chalcopyrite leaching in either ferric sulphate or cupric sulphate media in the presence of NaCl.
    (2016) Veloso, Tácia Costa; Peixoto, Johne Jesus Mol; Pereira, Márcio Salgado; Leão, Versiane Albis
    The shrinking core model (SCM) has been extensively applied in the kinetics analysis of particulate systems. This is because in its classical form it is one of the simplestmodels developed for fluid–solid reactions. However, it requires single-sized solid grains failing to describe the leaching kinetics for broad particle size distributions (PSDs). The current investigation successfully applied an extension of the SCM to the leaching of chalcopyrite with a broad PSD in a mixed chloride–sulphate solution. Such a medium was selected because there is renewed attention to leaching in mixed systems due to the increasing utilization of saline waters in both leaching and bioleaching of sulphide ores. Moreover, chloride is a catalyst of chalcopyrite leaching. Specifically, the effects of temperature (70 °C to 90 °C) and reagent (Fe3+, Cu2+ and Cl−) concentrations on the leaching kinetics were determined. The results showed that chalcopyrite leaching was faster with Cu2+ (larger rate constant) than with Fe3+, but the activation energy was similar in both cases with 66.6 kJ/mol for 0.5 mol/L of Cu2+ and 66.8 kJ/mol with 1.0 mol/L Fe3+.