Extender Properties of Some Nigerian Clays

Abstract

The extender properties of some Nigeria clays have been studied. The local clays were characterized using X-ray fluorescence and scanning electron microscope. The physico-chemical properties of the clays were evaluated using ASTM standards. The physico-chemical characterization of the local clays gave the following results: specific gravity (2.54 and 2.49), oil absorption (51.0 and 59.0 g/100g), refractive index (1.7 and 2.0) and pH (5.1 and 4.8) for Nsu and Ihitte-Uboma clays respectively. Compositional analysis showed that the clays consisted predominantly of silica (SiO2) and aluminium oxide (Al2O3) in high proportions with the other constituents present in very small proportions. The clays were stable to heat and insoluble in toluene, methanol, ethanol, 2-propanol, chloroform and hydrochloric acidexcept for their slight solubility in acetic acid. The colour of the clays was not affected in cold or when heated except for slight colour change observed in the presence of hydrochloric acid when heated. The particle morphology of the clays indicated the presence of sub-angular platelet of varying sizes. The optimum calcination temperature of the clays was determined to be 850°C for use in oil-based paints. The clays can be used in gloss paints, rubber and plastic composites and as an adsorbent with improved properties.