Abstract

Clays contain varying amounts of co-occurring non-clay minerals and lesser amounts of organic materials. Characterization of the clays in the Central Anatolian region (Turkey) was carried out using the spectroscopic techniques and results were qualitatively interpreted in terms of non-clay minerals found in the clays. The DTA-TGA measurements have been carried out for determinations of thermal behaviour of the clay samples. The FTIR spectra of clays known as standard clays such as illite, illite-smectite mixed layer, montmorillonite, Ca-montmorillonite, Na-montmorillonite, kaolinite, chlorite (ripidolite),palygorskite were first taken, and then the spectra of anhydrite, gypsum, illite+quartz+feldspar, quartz+feldspar were taken together with the standard clays. The minerals present in the samples were identified by comparing their FTIR spectra with those of the standard clay minerals and XRD results. Silica polymorphs, quartz being the most abundant, zeolites, feldspars, calcite, dolomite, and magnesite are the most common non-clay occurring in association with the clays. It is observed that bentonites are more frequently associated with silica, zeolites, feldspars, calcite, and dolomite, while kaolinites are often accompanied by silica, calcite and alunite. However, magnesite, dolomite and calcite co-occur commonly with sepiolite and palygorskite.

Key words: Non-clay minerals, FTIR, XRD, carbonates, zeolites, feldspars.