Physical, chemical and mineralogical characterisation of hydraulically disposed fine coal ash from SASOL Synfuels

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dc.contributor.author Mahlaba, Jabulani Samuel
dc.contributor.author Kearsley, Elsabe P.
dc.contributor.author Kruger, Richard A.
dc.date.accessioned 2011-05-27T06:47:13Z
dc.date.available 2011-05-27T06:47:13Z
dc.date.issued 2011-07
dc.description.abstract Coal serves as the primary energy source in most parts of the world. It is a fact that coal combustion yields enormous quantities of fly ash some of which are either hydraulically placed or dry dumped. The current study attempts to provide a comprehensive characterisation of a disused alkaline fine coal ash dam (FCAD) towards assessing environmental impact, rehabilitation and utilisation potential. Fine coal ash refers to a combination of approximately 83% power station fly ash and 17% gasification and bottom ash fines (particles <250 lm) at SASOL Synfuels. The hydration products found in Weathered Fine Coal Ash (WFCA) using X-ray Diffraction (XRD) and Differential Scanning Calorimetry (DSC) are analcime, calcite, C–S–H gel, ettringite, hydrated gehlenite (Strätlingite), magnetite, periclase, pyrrhotite and sillimanite. High resolution Scanning Electron Microscope (SEM) results provide additional proof that hydration products are present in WFCA. No indication of appreciable leaching was given by X-ray Fluorescence (XRF) results except calcium and silicon. Thus evidence exists that pollutants from saline brines are immobilised in WFCA and an insight of reaction kinetics was obtained. High content of amorphous phase and lack of alteration in some geotechnical properties suggest that WFCA can be reutilised with lime addition to increase alkalinity and activate pozzolanic reactions. en_US
dc.description.sponsorship The authors would like to thank SASOL Technology R&D (Pty) Ltd for sponsoring this project. en_US
dc.identifier.citation Mahlaba, JS, Kearsley, EP & Kruger, RA 2011, 'Physical, chemical and mineralogical characterisation of hydraulically disposed fine coal ash from SASOL Synfuels', Fuel, vol. 90, no. 7, pp. 2491-2500. [http://www.elsevier.com/locate/fuel] en_US
dc.identifier.issn 0016-2361 (print)
dc.identifier.issn 1873-7153 (online)
dc.identifier.other 10.1016/j.fuel.2011.03.022
dc.identifier.uri http://hdl.handle.net/2263/16641
dc.language.iso en en_US
dc.publisher Elsevier en_US
dc.rights © 2011 Elsevier Ltd. All rights reserved. en_US
dc.subject Coal combustion by-products en_US
dc.subject Fine coal ash dam en_US
dc.subject C–S–H gel en_US
dc.subject Chemical weathering en_US
dc.subject Hydration products en_US
dc.title Physical, chemical and mineralogical characterisation of hydraulically disposed fine coal ash from SASOL Synfuels en_US
dc.type Postprint Article en_US


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