Comparative analysis of physical and chemical characteristics of selected clays deposits found in Kebbi State, Nigeria

Abstract

The intent of this paper was to explore the physical and chemical characteristics of clays in Kebbi State, Nigeria, and the clays were compared with standard clay which is considered with highest quality standard in casting. Clay’s deposits from Dukku River along River Rima, Jega River which is the tail end of River Niger and Yauri were investigated for their potentials as raw materials used for casting and ceramic industries. Samples were collected from three local governments’ areas at the bank of the Rivers. Chemical analyses of individual clay were determined by employing four different techniques as follows; Complexiometric Titration, Atomic Absorption Spectrophotometer (AAS), X-Ray Diffraction (XRD), and X-Ray Fluorescence (XRF). The data collected from the analyses revealed that the structures of clay minerals were mainly kaolinite, Smectite (bentonite), and illite, and non-clay minerals for the three places were mainly quartz, feldspars and gibbsite. The results obtained revealed high silicate clays and moderate alumina content with trace elements of oxides (Fe2O3, CaO, K2O, TiO2, MgO, MnO, Na2O) also present within acceptable limits. Physical tests results at 900°C and 1300°C were used to determine firing shrinkage, colour, and modulus of rupture, bulk modulus, apparent density, crack formation, apparent porosity, water absorption, and bulk densities. The modulus of rupture, bulk densities, and fired linear shrinkage of all the samples increase with increasing firing temperature. The findings of this work revealed that the clays minerals from Dukku and Yauri had the necessary properties for the foundry work and refractory applications, but clays from Jega, can be exploited for commercial purposes after beneficiation by reducing the level of iron, quartz and other impurities. Key words: Clay minerals, chemical analysis, firing characteristics, oxides.