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Location
Lexington, Kentucky
Start Date
5-5-2026 2:00 PM
End Date
5-5-2026 2:30 PM
Description
Due to the ongoing need for critical minerals, coal combustion residuals (CCR), like fly ash, have been evaluated as a potential source of critical minerals, particularly rare earth elements (REEs). Previous studies have found that REEs in fly ash are largely contained within aluminosilicate glass from which they are difficult to extract. However, these studies have predominantly studied CCR from conventional pulverized coal fired (PCF) plants. PCF plants use higher temperatures (≥1300°C) than do circulating fluidized-bed (CFB) plants (~900-950°C). Samples of feed coal, fly ash, and bottom ash were collected from two adjacent Vietnamese coal-fired power stations, one with a PCF boiler and the other with a CFB boiler. The samples were analyzed for bulk geochemical and mineralogical compositions using inductively coupled plasma mass spectrometry and X-ray diffraction and for mineral morphology and chemistry using scanning electron microscopy. Although CCR from both plants exhibited similar major-element chemistry and relative REE concentrations (230-340 ppm), mineralogical analysis showed substantial differences. The lower-temperature CFB CCR contained clay minerals (e.g., kaolinite) preserved from the feed coal, whereas the higher-temperature PCF CCR consisted largely of glassy aluminosilicate spheres formed from clay melting. Feature analysis through energy-dispersive X-ray spectroscopy indicated that REE-rich mineral particles accounted for a higher proportion of the total REE content in the CFB CCR samples relative to the PCF CCR samples. This result suggests that REEs in the PCF CCR are likely disseminated in other particle types, meaning that the optimal extraction method for REEs from the two CCR sources could differ.
Document Type
Presentation
Archival?
Archival
Included in
Energy Systems Commons, Environmental Indicators and Impact Assessment Commons, Environmental Monitoring Commons, Mining Engineering Commons, Oil, Gas, and Energy Commons, Structural Materials Commons, Sustainability Commons
Comparison of Residuals from Neighboring Power Stations with Different Coal Combustion Technologies
Lexington, Kentucky
Due to the ongoing need for critical minerals, coal combustion residuals (CCR), like fly ash, have been evaluated as a potential source of critical minerals, particularly rare earth elements (REEs). Previous studies have found that REEs in fly ash are largely contained within aluminosilicate glass from which they are difficult to extract. However, these studies have predominantly studied CCR from conventional pulverized coal fired (PCF) plants. PCF plants use higher temperatures (≥1300°C) than do circulating fluidized-bed (CFB) plants (~900-950°C). Samples of feed coal, fly ash, and bottom ash were collected from two adjacent Vietnamese coal-fired power stations, one with a PCF boiler and the other with a CFB boiler. The samples were analyzed for bulk geochemical and mineralogical compositions using inductively coupled plasma mass spectrometry and X-ray diffraction and for mineral morphology and chemistry using scanning electron microscopy. Although CCR from both plants exhibited similar major-element chemistry and relative REE concentrations (230-340 ppm), mineralogical analysis showed substantial differences. The lower-temperature CFB CCR contained clay minerals (e.g., kaolinite) preserved from the feed coal, whereas the higher-temperature PCF CCR consisted largely of glassy aluminosilicate spheres formed from clay melting. Feature analysis through energy-dispersive X-ray spectroscopy indicated that REE-rich mineral particles accounted for a higher proportion of the total REE content in the CFB CCR samples relative to the PCF CCR samples. This result suggests that REEs in the PCF CCR are likely disseminated in other particle types, meaning that the optimal extraction method for REEs from the two CCR sources could differ.
