The Sulphocalcic coal fly ashes of Ptolemais (Macedonia, Greece) and Gardanne (Provence, France)

European Seminar Coal Fly Ash: a Secondary raw Material. Marseille, Francia, 18 April 1997.Proceedings, 1997, 149-158[EN] Morphological, mineralog1ca l and chemical characteristics of lignite fly ashes of Ptolemais (Greece) and Gardanne (France), were studied using Scanning Electron Microscopy (SEM-EDS), X-Ray Diffraction (XRD) technique, Atomic Absorption Spectrometry (AAS) and !nductively Coupled Plasma - Mass Spectrometry (ICP-MS). In Ptolemais area, the five power plants (installed capacity of 3,689 MW) use pulverized lignite as fuel and produce around 7 million t/y of fly ash. The 600 MW unit 5 of Gardanne is using also lignite as fuel, but applying forced desulphurization during the combustion (mixing limestone into the lignite and completed by lime injection into the furnace). The annual production of fly ash in the unit 5 of Gardanne is approximately 300,000 tons. Morphologically, the fly ashes consist of irregularly shaped, oval and spherical particles. Concerning the major and minor/trace mineral phases, differences between the two fly ashes are observed. However, anhydrite, lime and quartz are contained as major phases in both fly ashes. Chemically, the fly ashes are mainly composed of CaO, SiO2, Al2O3 and SO3. The Garcanne fly ash is richer In CaO and SO3, while the fly ash of Ptolemais is richer in SiO2 and Al2O3. Compared with the global concentration ranges in coal ash, the majority of the trace elements analysed, display overall low contents. Utilization and environmental aspects in relation to the morphological, mineralogical and chemical characteristics of the fly ashes, are considered and discussed.Peer reviewe