Title of article :
Physical, chemical and mineralogical characterisation of hydraulically disposed fine coal ash from SASOL Synfuels
Author/Authors :
Mahlaba، نويسنده , , Jabulani S. and Kearsley، نويسنده , , Elsabé P. and Kruger، نويسنده , , Richard A.، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2011
Pages :
10
From page :
2491
To page :
2500
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 μm) 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.
Keywords :
Fine coal ash dam , C–S–H gel , Hydration products , Chemical Weathering , Coal combustion by-products
Journal title :
Fuel
Serial Year :
2011
Journal title :
Fuel
Record number :
1466866
Link To Document :
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