Characterization of rectorite from the Beatrix Gold Mine in South Africa

Show simple item record Atanasova, Maria T. Vyalikh, Anastasia Scheler, Ulrich Focke, Walter Wilhelm 2016-04-26T08:20:13Z 2016-06
dc.description.abstract Three rectorite samples from the Beatrix Gold Mine, South Africa were characterized. Scanning electron microscopy revealed a layered morphology. High resolution transmission microscopy showed well distinguished light and dark layers of about 2.20 nm consistent with the 1:1 interstratified mica-smectite nature. X-ray diffraction measurements confirmed the basal spacing d001 of 2.20 nm consistent with a one-water-layer structure. Unit cell parameters, for a monoclinic unit cell with primitive lattice, refined to a = 5.177 Å; b = 8.980 Å; c = 22.489 Å and β = 97.335° with mean crystallite size around 14 nm and calculated cell volume of 1045 Å3. The Greene-Kelly test suggested that the expandable smectite layers have montmorillonite-beidellite composition. Nuclearmagnetic resonance spectroscopy indicated a high degree of Al substitution and the presence of two different Al sites corresponding to six- and four-fold octahedral and tetrahedral aluminumrespectively. The chemical composition and diffraction data suggest that the mica is Na-Ca-rich, i.e. of paragonite-margarite series. The fixed interlayer regions (mica interlayers) contains proportionally dominant Na+ and Ca2+ and minor amounts of K+. The exchangeable smectitic interlayers contain almost equal amounts of Na+ and Ca2+ ions. The distribution of the interlayer Na+ ions was quantified by 23Na solid-state NMR spectroscopy. It points to a three component mixed-layer structure with considerable variation in the composition of the mica layer of the different samples. en_ZA
dc.description.department Chemical Engineering en_ZA
dc.description.embargo 2017-07-31
dc.description.librarian hb2016 en_ZA
dc.description.sponsorship Algeria/South Africa Collaboration Programme (Grant 87453) of the National Research Foundation (NRF). en_ZA
dc.description.uri en_ZA
dc.identifier.citation Atanasova, MT, Vyalikh, A, Scheler, U & Focke, WW 2016, 'Characterization of rectorite from the Beatrix Gold Mine in South Africa', Applied Clay Science, vol. 126, pp. 7-16. en_ZA
dc.identifier.issn 0169-1317 (print)
dc.identifier.issn 1872-9053 (online)
dc.identifier.other 10.1016/j.clay.2016.02.028
dc.language.iso en en_ZA
dc.publisher Elsevier en_ZA
dc.rights © 2016 Elsevier B.V. All rights reserved. All rights reserved. Notice : this is the author’s version of a work that was accepted for publication in Applied Clay Science. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Applied Clay Science, vol. 126, pp. 7-16, 2016. doi : 10.1016/j.clay.2016.02.028. en_ZA
dc.subject Rectorite en_ZA
dc.subject Mixed-layer en_ZA
dc.subject Interstratification en_ZA
dc.subject Solid-state NMR en_ZA
dc.subject Thermal analysis en_ZA
dc.subject Scanning electron microscopy (SEM) en_ZA
dc.subject Fourier transform infrared spectroscopy (FTIR) en_ZA
dc.subject X-ray powder diffraction (XRD) en_ZA
dc.title Characterization of rectorite from the Beatrix Gold Mine in South Africa en_ZA
dc.type Postprint Article en_ZA

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