Mineralogy, chemistry and potential utilization of clays from coal deposits in the Kütahya province, Western Turkey

Kütahya graben is one of the largest E–W trending grabens of Western Turkey consisting of Tavşanlı and Seyitömer sub-basins filled with Neogene continental deposits. These deposits contain economic lignite seams and the clay samples investigated in this study are closely related to the commercial lignite deposits since they occur underlying or overlying the major coal seams and also intercalated with them.Petrographical, chemical, XRD, SEM-EDX, DTA-TG analyses and some technological tests were performed on 51 clay samples collected from different open-pit mines within Tavşanlı and Seyitömer sub-basins to determine their mineralogical, chemical and technological properties and to evaluate their potential industrial uses. Their swelling properties, dispersion in water, plasticity, sand and carbonate contents, and thermal behaviours were tested.Analysis showed that major clay minerals are smectite, kaolinite, chlorite, illite and illite–smectite mixed-layer varieties and non-clay minerals are quartz, feldspar, dolomite, calcite and siderite. Tavşanlı sub-basin samples are rich in kaolinite whereas Seyitömer sub-basin samples are rich in smectite and illite. Siderite and dolomite are present only in Tavşanlı while aragonite and cristobalite were detected in the Seyitömer sub-basin. In general, the studied clays are suitable raw materials for ceramic and tile industries. However, a clay source restricted to the Tavşanlı sub-basin is available for use in the cement industry.