Title: Leaching kinetics of limonite and nontronite ores

Authors: Jessica Tang, Marjorie Valix

Addresses: School of Chemical and Biomolecular Engineering, The University of Sydney, NSW 2006, Australia. ' School of Chemical and Biomolecular Engineering, The University of Sydney, NSW 2006, Australia

Abstract: Bioleaching of nickel laterite ores is the extraction technology based on the use of heterotrophic micro-organisms and their organic acid products to dissolve metals from oxide minerals. This study examined the leaching kinetics of limonite and nontronite ores by metabolites including citric, lactic and malic acids. In addition the roles of acidolysis and complexolysis in the kinetic of metal dissolution were examined. The leaching process was found to follow the chemically controlled model. The roles of acidolysis and complexolysis on the kinetics of leaching were found to depend on the leaching conditions. Acidolysis is the most important under acidic conditions but under weaker acidic conditions the complexolysis become dominant. These results suggest the importance of both acid activity and the nature of complexing agents in dissolving metals such as nickel and cobalt from laterite minerals.

Keywords: nickel laterite ores; leaching kinetics; limonite; nontronite ores; acidolysis; complexolysis; bioleaching; metabolites; citric acid lactic acid; malic acid; metal dissolution; cobalt; green technologies.

DOI: 10.1504/IJEWM.2009.026341

International Journal of Environment and Waste Management, 2009 Vol.3 No.3/4, pp.244 - 252

Published online: 07 Jun 2009 *

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