The production and use of citric acid for the removal of potassium from the iron ore concentrate of the Sishen Iron Ore Mine, South Africa

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dc.contributor.authorWilliams, Peter J.
dc.contributor.authorCloete, Thomas E.
dc.date.accessioned2011-05-15T15:55:09Z
dc.date.available2011-05-15T15:55:09Z
dc.date.issued2010-03
dc.descriptionThe original publication is available at http://www.sajs.co.za/
dc.description.abstractThe depletion of the richer iron ore worldwide has made it necessary to process lower quality iron ore. Certain substances, such as potassium, contained within the lower quality iron ore, have a detrimental effect on the smelting process during steel manufacturing. Therefore, international steel-making companies charge penalties when purchasing iron ore concentrates containing high concentrations of potassium. To date, lower quality iron ore has been blended with high quality iron ore in an attempt to alleviate the potassium concentrations in the export iron ore; however, the ratio of low quality iron ore to high quality iron ore is increasing, thereby becoming an escalating problem within the economic functioning of the Sishen Iron Ore Mine. It has, therefore, become necessary to develop an economically viable and environmentally friendly process to reduce the high potassium concentrations contained in the iron ore concentrate of the Sishen Iron Ore Mine. In this study, we compared solid substrate and submerged fermentation using Aspergillus niger for the production of citric acid, which is used for the chemical leaching of potassium from the iron ore concentrate. It was found that submerged fermentation proved to be more economical and efficient, producing a maximum citric acid concentration of 102.3 g/L in 96 h of fermentation. 'Heap leaching' simulation experiments were found to be uneconomical, due to the required addition of fungal growth medium every 5 days as a result of growth factor depletion within this time; however, this process removed 17.65% of the potassium from the iron ore concentrate. By contrast, chemical leaching of potassium from the iron ore concentrate proved to be most efficient when using a 1 mol citric acid leaching solution at 60 °C, removing 23.53% of the potassium contained within the iron ore concentrate. Therefore, the most economical and efficient process for the removal of potassium from the iron ore concentrate of the Sishen Iron Ore Mine involved a two-stage process whereby citric acid was produced by A. niger, followed by the chemical leaching of the potassium from the iron ore concentrate using a 1 mol citric acid leaching solution at 60 °C. © 2010. The Authors.en_ZA
dc.description.versionPublishers' versionen_ZA
dc.identifier.citationWilliams, p. J. & Cloete, T. E. 2010. The production and use of citric acid for the removal of potassium from the iron ore concentrate of the Sishen Iron Ore Mine, South Africa. South African Journal of Science, 106(3/4), doi:10.4102/sajs.v106i3/4.158.en_ZA
dc.identifier.issn1996-7489 (online)
dc.identifier.issn0038-2353 (print)
dc.identifier.otherdoi:10.4102/sajs.v106i3/4.158
dc.identifier.urihttp://hdl.handle.net/10019.1/9615
dc.publisherAcademy of Science of South Africa (ASSAf)
dc.rights.holderAuthors retain copyright
dc.subjectCitric aciden_ZA
dc.subjectCost effectivenessen_ZA
dc.subjectFermentationen_ZA
dc.subjectFungien_za
dc.subjectIron ores -- Geologyen_ZA
dc.subjectLeachingen_ZA
dc.subjectMines and mineral resourcesen_ZA
dc.subjectPotassiumen_ZA
dc.subjectSmeltingen_ZA
dc.titleThe production and use of citric acid for the removal of potassium from the iron ore concentrate of the Sishen Iron Ore Mine, South Africaen_ZA
dc.typeArticleen_ZA
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