Element enrichments and modes of occurrence in the feed coals and coal ashes of the Türkiye thermal power plants

The trace elements enrichments and modes of occurrence were investigated in the feed coals and coal ashes from the thermal power plants Tunçbilek (Kütahya), Soma-Torku and Soma-Kolin (Manisa), Çan 18 Mart (Çanakkale), Yatağan, Yeniköy, Kemerköy (Muğla), Tufanbeyli (Adana), Çatalağzı (Zonguldak), Çayırhan (Ankara), and Elbistan-B (Kahramanmaraş). The Ni, As, Cr and Th concentrations are higher than the World coal averages in the feed coals of almost all power plants. On the other hand, Ni, Cr, Rb, As, and V in the bottom ashes and Ni, Cr, As, U, B, Li, V, Rb, Cd, and Zn in the fly ashes, are higher than the World coal ash averages. The similar element enrichments were observed in both the bottom and fly ashes related to the element enrichments in the feed coals. Siderophile and chalcophile elements such as Ni, Zn, Pb, and Cd are generally associated with iron oxides, spinels, or metal carbonates in coals and coal ashes. In contrast, lithophile elements such as Li, U, B, Th, Ba, Sr, and V are typically present within carbonates, borates, sulfates, oxides, or organic matter in coals, whereas, in ashes, they are more commonly associated with glass phases, carbonates, and sulfates.