The determination of kaolinite clay content in limestones of western Tamil Nadu by methylene blue adsorption using UV–vis spectroscopy

The clay index values of 60 different limestone samples collected from western Tamil Nadu were determined using UV–vis spectrophotometric method with the help of the absorbance value at 663 nm of a known concentration of methylene blue. The type of clay was determined as kaolinite through the FTIR technique. The applicability of this approach and advantages over the current methods in cement and chemical industries are demonstrated. According to the clay index values, the quality of the samples obtained from Padaivedu area of Namakkal district is better than the other samples.