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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2 resultados
Resultados da Pesquisa
Item The effects of fluoride and aluminum ions on ferrous-iron oxidation and copper sulfide bioleaching with Sulfobacillus thermosulfidooxidans.(2012) Veloso, Tácia Costa; Sicupira, Lazaro Chaves; Rodrigues, Isabel Cristina Braga; Silva, Larissa A. M.; Leão, Versiane AlbisMicroorganisms that grow at high temperatures can improve Fe(II) bio-oxidation and thereby its technological applications, such as bioleaching and H2S removal. Conversely, elements present in industrial growth media, such as fluoride, can inhibit bacterial growth and iron bio-oxidation. In this work, the influence of fluoride on the kinetics of ferrous-iron bio-oxidation with Sulfobacillus thermosulfidooxidans was investigated. The effects of fluoride concentrations (0–0.5 mmol L−1) on both iron oxidation and bacterial growth rates were assessed. In addition, the effect of the addition of aluminum, which was intended to complex free fluoride and reduce the concentration of HF through the formation of aluminum–fluoride complexes, was also investigated. The results show that 0.5 mmol L−1 NaF completely inhibited bacterial growth within 60 h. Nevertheless, fluoride toxicity to S. thermosulfidooxidans was minimized by control of the aluminum–fluoride ratio in the system because, at a 2:1 aluminum–fluoride molar ratio, bacterial growth was similar to that observed in the absence of fluoride ions. Despite a slower bacterial growth rate, fluoride concentrations less than the inhibitory concentration increased the Fe(II) oxidation rate. Successful copper bioleaching (80–100%) from fluoride-containing sulfide ores (1% total fluoride) was demonstrated in the presence of aluminum.Item Kinetics of ferrous iron oxidation by Sulfobacillus thermosulfidooxidans.(2010) Pina, Pablo dos Santos; Oliveira, Víctor de Andrade Alvarenga; Cruz, Flávio Luciano dos Santos; Leão, Versiane AlbisThe biological oxidation of ferrous iron is an important sub-process in the bioleaching of metal sulfides and other bioprocesses such as the removal of H2S from gases, the desulfurization of coal and the treatment of acid mine drainage (AMD). As a consequence, many Fe(II) oxidation kinetics studies have mostly been carried out with mesophilic microorganisms, but only a few with moderately thermophilic microorganisms. In this work, the ferrous iron oxidation kinetics in the presence of Sulfobacillus thermosulfidooxidans (DSMZ 9293) was studied. The experiments were carried out in batch mode (2L STR) and the effect of the initial ferrous iron concentration (2–20 g L−1) on both the substrate consumption and bacterial growth rate was assessed. The Monod equation was applied to describe the growth kinetics of this microorganism and values of max and Ks of 0.242 h−1 and 0.396 g L−1, respectively, were achieved. Due to the higher temperature oxidation, potential benefits on leaching kinetics are forecasted.