Mineralogical and geochemical characterisation of kaolin deposit from Debre Tabor area northwestern, Ethiopia

摘要

Debre Tabor kaolin deposit is located around Debre Tabor town in Amhara region of northwestern Ethiopia. The kaolin deposit in the study area needs a detailed study to evaluate the geological, mineralogical, physical, and geochemical conditions. For this purpose, detailed geological, physical, mineralogical, and geochemical laboratory tests were performed. XRD and petrographic analysis were used to study the mineralogical composition. Geochemical analysis was determined using ICP-MS and ICP-AES. The Debre Tabor kaolin deposit is exposed along riverbanks, road cuts, hillside, and quarry sites. The laboratory results reveal that the deposit is formed from the weathering of felsic rocks mainly trachyte and tuff units. From the laboratory analysis, we found that quartz is the dominant impurities. The geological, mineralogical, and geochemical studies indicate that in situ weathering followed by leaching played a major role in the formation of the Debre Tabor kaolin deposit. The average Chemical Index of Alteration (77.98%) shows that the host rock has experienced moderate weathering and alteration under the hot and humid climatic conditions of the subtropical zone. The low bulk density (1.54 g cm~(-3)) and Ce + Y+La vs. Ba + Sr plot correspond to the supergene type of formation. Based on the mineralogical, geochemical, and physical properties, Debre Tabor kaolin deposit can be used for refractory, ceramics, paper coating, and filler (paint) industries, but treatment is important to remove the existing impurities such as iron, quartz, and feldspars.