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Microbially induced selective flocculation of hematite from kaolinite

Poorni, S and Natarajan, KA (2013) Microbially induced selective flocculation of hematite from kaolinite. In: INTERNATIONAL JOURNAL OF MINERAL PROCESSING, 125 . pp. 92-100.

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Official URL: http://dx.doi.org/10.1016/j.minpro.2013.10.002


Microbially induced selective flocculation of hematite from kaolinite has been demonstrated using Bacillus subtilis. Growth of bacterial cells in the presence of kaolinite resulted in enhanced production of extracellular proteins while that of hematite promoted significant secretion of exopolysaccharides. Bacterial cells were adapted to grow in the presence of the minerals and use of hematite-grown and kaolinite-grown cells and their metabolic products in the selective flocculation of hematite and dispersion of kaolinite illustrated. Bacterial cells and extracellular polysaccharides exhibited higher surface affinity towards hematite, rendering it hydrophilic; while significant protein adsorption enhanced surface hydrophobicity of kaolinite. Bacterial interaction with hematite and kaolinite resulted in significant surface chemical changes on the minerals. Due to higher surface affinity towards extracellular proteins, zeta potentials of kaolinite shifted in the positive direction, while those of hematite shifted in the negative direction due to higher adsorption of extracellular polysaccharides. Bacterial interaction promoted selective flocculation of only hematite, while kaolinite was efficiently dispersed. Mineral-specific stress proteins were generated on growing B. subtilis in the presence of kaolinite. Interfacial aspects of microbe-mineral interactions are illustrated to explain microbially-induced selective flocculation of hematite from kaolinite with relevance to clay and iron ore beneficiation. (C) 2013 Elsevier B.V. All rights reserved.

Item Type: Journal Article
Additional Information: Copyright for this article belongs to ELSEVIER SCIENCE BV, NETHERLANDS
Keywords: Bacillus subtilis; Selective flocculation; Hematite; Kaolinite
Department/Centre: Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Depositing User: Id for Latest eprints
Date Deposited: 29 Jan 2014 06:11
Last Modified: 29 Jan 2014 06:11
URI: http://eprints.iisc.ac.in/id/eprint/48266

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