Petrographic characterization of economizer fly ash
Minerals & Metallurgical Processing, 2009, Vol. 26, No. 4, pp. 208-216
Valentim, B.; Soares, S.; Guedes, A.; Garcia, C.; Flores, D.; Hower, J.C.; Oliveira, A.
Policies for reducing NOx emissions have led power plants to restrict O2, resulting in high-carbon fly ash production. Therefore, some potentially useful fly ash, such as the economizer fly ash, is discarded without a thorough knowledge of its composition. In order to characterize this type of fly ash, samples were collected from the economizer of a Portuguese power plant burning two low-sulfur bituminous coals. Characterization was also performed on economizer fly ash subsamples after wet sieving, density and magnetic separation. Analysis included atomic absorption spectroscopy, loss-on-ignition, scanning electron microscopy/energy-dispersive X-ray spectroscopy, optical microscopy, and micro-Raman spectroscopy.