Physicochemical characterisation and industrial application of new kaolin deposit in Sela Dingay Area, Central Ethiopia

Sela Dingay kaolin deposit is a primary deposit formed mainly through the weathering of rhyolitic ignimbrite. Integrated analyses of geological, mineralogical, geochemical and physical properties were conducted to characterise the industrial applications of Sela Dingay kaolin. X-ray diffraction (XRD) and attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR) were used to characterise the raw kaolin samples. The results show that Sela Dingay kaolin is mainly composed of kaolinite (66–93%) and quartz (9–34%). The higher chemical index of alteration (CIA = 94.2%) and chemical index of weathering (CIW = 96.8%) values suggest that Sela Dingay kaolin was formed by intense chemical weathering under oxidising conditions. Sela Dingay kaolinite deposit consists of high percentage of clay/silt-sized particles, a low shrinkage value (1.1–3.4%), medium-high plastic limit (25–35%), with specific gravity and pH values ranging between 2.47 and 2.56 g/cm 3 and 6.3 and 7.2, respectively. The overall results show that Sela Dingay kaolin is medium to high grade and it can be used for various industrial applications with appropriate beneficiation processes to remove higher amounts of Fe 2 O 3 and quartz. Therefore, the newly discovered kaolin deposit (estimated at 5,136,166 tonnes) in the Sela Dingay area is a potential target for future kaolin exploitation.