Clays and Clay Minerals, Vol. 57, No. 6, 787–794, 2009.
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Authors
Arslan, Volkan
Bayat, Oktay
Issue Date
2009
Type
Article
Language
Keywords
Periodicals , Geology , Aspergillus niger , Bioleaching , Chemical Leaching , Kaolin , Yates’ Technique
Alternative Title
Removal Of Fe From Kaolin By Chemical Leaching And Bioleaching
Abstract
The use of microorganisms to remove Fe (oxyhydr)oxides from kaolins has the potential to be an effective method for upgrading the whiteness and brightness, and therefore the commercial value, of the kaolin. The purpose of the present study was to compare kaolin products obtained by currently used chemical leaching methods with a bioleaching treatment using Aspergillus niger in order to remove Fe from kaolin (from Canakkale, Turkey). The effects of pulp density, temperature, and oxalic acid concentration on the chemical leaching experiments were investigated using the ANOVA-Yates test. The greatest degree of removal of Fe from the kaolin sample (at 15% w/v pulp density, temperature of 80ºC, oxalic acid concentration of 0.2 M, and a particle size of <63 mm) was found to be 94.89% in 120 min of leaching. The Fe content decreased from 1.723% Fe2O3 to0.088% Fe2O3. In a shake flask, bioleaching of kaolin by Aspergillus niger resulted in removal of 77.13% of the total Fe, suggesting that this strain is effective at removing Fe impurities from kaolin. The removal efficiency generally decreased with increased pulp density. The Fe content of the kaolin decreased from 1.723% Fe2O3 to0.3 94% Fe2O3 (at 1% w/v pulp density, temperature of 25ºC, Aspergillus niger 36107 spores, and particle size of <63 mm) after 21 days of bioleaching
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Citation
Clays and Clay Minerals, Vol. 57, No. 6, 787–794, 2009.
Publisher
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