Mineralogical and physicochemical characterization of bentonite deposit of Gidicho Island in Lake Abaya, Southern Main Ethiopian Rift

The present study investigates the geochemical, mineralogical, morphological and physical properties of Gidicho bentonite deposits to determine its grade and quality using X-ray fluorescence (XRF), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and physical tests. The XRD and FTIR results reveal that Gidicho bentonite consists of Ca-montmorillonite with minor kaolinite, quartz and feldspar minerals. SEM image shows spongy and flaky structures stacked together to form agglomerates. The geochemical results suggest that the bentonite was formed by a moderate degree of weathering in arid and semi-arid environments. Na 2 O/CaO ratio indicate non-swelling bentonite with tolerable quality and grade. The physical characteristics show that 77 meq 100 g −1 cation exchange capacity, 17.1 ml 2 g −1 swelling index with 30.1% optimum moisture. Bulk density and specific gravity ranges from 1.64–1.67 g cm −3 and 2.23-2.4 g cm −3 , respectively. The overall results revealed that the Gidicho bentonite can be used for many industrial applications with appropriate beneficiation methods.