Chemical investigation of lignite samples and their ashing products from Kardia lignite field of Ptolemais, Northern Greece

Twenty-six lignite samples were collected from the Kardia lignite field (Ptolemais, Greece). Ash content, moisture and CO2 were determined. The lignite samples were heated at 900 °C producing 26 ash samples. The chemical composition (major and trace elements) both of the lignite samples and ash products was determined using INAA, ICP-OES and ICP-MS. CaO, SiO2 and Al2O3 are the dominant oxides both in lignite and ash samples. A relative decrease of SiO2 and Al2O3 as well as an increase of CaO was noticed in the deeper lignite samples. Sr, Cr, Ni, V and Ba were found to be the most abundant both in lignite and ash samples. Sr displays a relative increase while Ni and Cr decrease with depth in the lignite samples. In the ash samples, Ni shows the most obvious decrease with depth.