Physicochemical characterization and industrial use of Awzet Kaolin deposit in Northwestern Ethiopian plateau

This study aimed to elucidate the mineralogy, geochemistry, genesis, and potential industrial applications of the Awzet kaolin deposit in northwestern Ethiopian Plateau. New geological, mineralogical, and physicochemical data were utilized to enhance understanding of its formation and uses. The primary lithologic units included unwelded tuff and basalt, with the parent rock identified as unwelded tuff. Several laboratory analyses were conducted using various techniques, including X-ray diffraction (XRD) for mineral identification and crystallinty characterization, Fourier transform infrared spectroscopy (FTIR) to analyze functional groups and crystallinity, scanning electron microscopy (SEM) for morphological assessments, and inductively coupled plasma (ICP) methods for geochemical analysis. Additionally, a range of physical tests were performed, including assessments of color, pH, Atterberg limits, grain size, bulk density, and specific gravity, to evaluate the suitability of the kaolin for various applications. Results indicated that the deposit primarily comprises kaolinite and quartz, formed through intense chemical weathering, as evidenced by high Chemical Index of Alteration (89.08%) and Chemical Index of Weathering (93.92%) values. Elevated concentrations of Ce + Y + La and Cr + Nb, along with the absence of quartz veining, suggest a supergene weathering process. Samples from the upper part of the deposit (LK2 and AKM) exhibited higher silt and clay contents of 76.8% and 80%, respectively, while bottom samples (LK1 and LKS2) showed lower fractions of 74.4% and 71.2%. The lower bulk density (average 1.25 g/cm³) and grain size distribution further support the supergene kaolinization process. Awzet kaolin samples demonstrated low linear shrinkage values (1.1%-3.5%), a pH range of 6.71-7.43, and preliminary colors of light greenish gray and pale yellow, indicating their potential suitability for applications in brick manufacturing, paper coating, fillers, ceramics, and agriculture.