Physico-Chemical, Mineralogical, and Chemical Characterisation of Cretaceous–Paleogene/Neogene Kaolins within Eastern Dahomey and Niger Delta Basins from Nigeria: Possible Industrial Applications

Abstract

The demand for kaolinitic clays for various industrial applications is increasing globally. The present study evaluated the potential industrial applications of kaolins from the Eastern Dahomey and Niger Delta Basins, Nigeria. The colour, pH, electrical conductivity (EC), particle size distribution (PSD), plastic limits and liquid limits of the kaolins were determined. Mineralogical properties were assessed using X-ray diffractometry (XRD), scanning electron microscopy (SEM), and differential thermal analysis (DTA). The chemical compositions of the kaolins were determined using X-ray fluorescence spectrometry (XRF). The kaolins were generally acidic, with pH less than 7 with low EC. The moderate plasticity indices (PI ≥ 10%) for the kaolins suggested their potential use in the manufacturing of structural clay products without extrusion. Kaolinite was the only kaolin mineral present with anhedral–subhedral–euhedral crystals. The platy morphology of the kaolinites in the Cretaceous kaolins are very important in paper production. Other minerals present in the kaolins were quartz, muscovite, anatase and goethite. The major oxide contents of the kaolins were dominated by SiO2, Al2O3, Fe2O3 and TiO2. Based on chemical specifications, the raw kaolins are not suitable for most industrial applications except for the Cretaceous Lakiri kaolins in the paper and ceramic industries (except for TiO2 and K2O content). The study concluded that the kaolin deposits would require beneficiation for large-scale industrial applications.