Characterization of clay deposits in Nachchaduwa area for ceramic fabrication

Abstract

In this research clay deposits located in the Nachchaduwa area were investigated to identify suitable ceramic fabrication techniques and products. Deposits located in this area are known to be rich in Kaolinite and Montmorillonite (MMT) and other type of phyrophyllite clays. These are known as "Red Clav" and mined to fabricate traditional ceramic ware by traditional techniques. The specimens were collected fr~m tanks located in this area and subjected to Fourier Transform Infrared Spectroscopy (FTlR). X-ray Diffraction (XRD). Differential Thermal Analysis (DTA) and Thermo Gravimetric Analysis (TGA). after purifying them and removing organic compounds. Combination of these techniques with the chemical analysis on selected specimens was employed to accurate identification of the clay specimens. The results were then compared with each other and published literature for the identification. Results showed the presence of MMT, kaolinite. quartz and other type of clay minerals in small quantities; furthermore specimens subjected to chemical analysis revealed that they contain more than 50% quartz by weight. The purified clay specimens were subjected to a Deflocculant Demand Test. which determines the optimum amount of deflocculant needed to prepare a casting slip. but the test showed that these claysare not suitable to prepare a casting slip in fabricating ceramic ware.