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

Abstract

Keywords:Coal fly ash Coal-fired power plants Trace element leaching 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).

Characterization and comparison of leaching behaviors of fly ash samples from three different power plants in Turkey

“…TCLP test which was used by a number of researchers [1,14,[29][30][31][32][33][34][35][36][37][38] was carried out to the samples to determine the potential leachability of some elements in acidic conditions. In addition, ASTM D3987 test was applied to find out the leach potential of the samples being exposed to normal environmental conditions.…”

“…Some studies also indicate that heavy metals favorably concentrate on the particle surfaces, making them more easily to be extracted from fly ash by the contact with aqueous solution in ponds and landfill areas [7,9,[11][12][13]. In addition, there are a great number of studies [9][10][11][12][14][15][16][17][18][19] on the leaching behavior of different elements from fly ash. Dissolution behavior of the elements in leaching environments mainly relates to the particle size, surface area, leaching solution and fly ash pH, initial concentrations of the elements, leaching period, solid/liquid ratio, morphological structure and the other features of the leach medium.…”

“…However, the rate of the process may be enhanced by stirring or shaking which increases the possibility and the efficiency of interactions between particles and leach solution. Therefore, by means of the shorter contact time, preliminary information can be obtained about the longlasting leaching process [7,14]. Toxicity Characteristic Leaching Procedure (USEPA TCLP 1311, 1992) [22] and Standard Test Method for Shake Extraction of Solid Waste with Water (ASTM D-3987-85, 2004) [23] are generally applied tests to various wastes for this aim.…”

“…Toxicity Characteristic Leaching Procedure (USEPA TCLP 1311, 1992) [22] and Standard Test Method for Shake Extraction of Solid Waste with Water (ASTM D-3987-85, 2004) [23] are generally applied tests to various wastes for this aim. Both tests can also be carried out for the determination of short-period leaching behaviors of fly ash samples in water and weakly acidic conditions such as acid rain [14]. However, in this process, not only leach medium properties but also fly ash properties are important.…”

Characterization of Inorganic Elements within PM2.5 and PM10 Fractions of Fly Ashes from Coal-Fired Power Plants

“…Higher levels of element contents in FAs are 4-10 times those of the feed coal, which should be an environmental concern (Akar et al, 2012). The elements associated with stockpiled FAs may enter into soils and ground waters and result in adverse environment impacts (Li et al, 2016).…”