Resumo

VAN DYK, L.D et al. Gas-phase extraction of lead and iron from their oxides in a fluidized-bed reactor. J. S. Afr. Inst. Min. Metall. [online]. 2012, vol.112, n.6, pp.461-465. ISSN 2411-9717.

The extraction of iron and lead from their oxides with a volatile organic ligand such as acetylacetone in the gas phase offers potential advantages of lower energy consumption, recycling of the extractant, recovery of pure metals, and a reduced environmental impact compared with conventional extraction processes. The influence of reaction temperature, ligand flow rate, and metal oxide levels on the extraction and rates of reaction of iron and lead from single metal oxide (synthetic haematite (Fe₂O₃) and synthetic massicot (PbO)) systems in a fluidized bed was studied. It was found that at the investigated acetylacetone flow rates, the influence of mass transfer was limited, but that the reaction suffered from reactant starvation. When the metal load increased the effect of starvation on the rate of reaction also increased. The reaction kinetics increased with an increase in temperature for both systems. At low metal oxide concentrations more that 80 per cent of the iron and lead could be extracted from their respective metal oxides after only four hours.

Palavras-chave : gas-phase extraction; leaching; iron(III) oxide; lead(II) oxide; acetylacetone.

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