Leaching behavior of selected trace elements in coal fly ash samples from Yenikoy coal-fired power plants

Short-term leaching test results of alkaline fly ash from Yenikoy coal-fired power plant were reported in this paper. ASTM D-3987-85 and TCLP-1311 test methods were applied to determine leaching behavior of selected elements namely, Fe, Ca, Cu, Co, Cd, Mn, Ni, Pb Zn, and Cr (VI) at different particle size fractions and test conditions. Chemical, mineralogical and morphological characterizations of ash samples were also performed using chemical, XRD and SEM–EDS analysis methods. The results showed that CaO dominates in the Yenikoy fly ash sample which directly affects the mobility of trace elements by determining the pH of the leaching medium. Higher mobility values of Cd, Co Cu, Pb, Ni and Zn elements were observed for TCLP-1311 procedure. The concentration of these elements in leachates showed a tendency to increase by decreasing particle size. Overall results suggested that the amount of the selected elements in the final leachates of both tests was lower than the limit values of landfill regulations except Cr (VI).

► Fly ash samples were collected simultaneously from Yenikoy coal-fired power plant.
► TCLP 1311 and ASTM 3987-85 toxicity test methods were applied to find out the mobility of some selected trace elements.
► Ca+2 was found as the most mobile element while Mn, Fe have the lowest mobility.
► Dissolution of trace elements is somewhat higher for the particles below 38 micron size.
► The following trend was found for the dissolution of selected trace elements; Ca> Fe>Mn>Pb>Ni>Zn≈Cu>Cd≈Co.