Investigation of unexplored kaolin occurrences in southern Mauritania and preliminary assessment of possible applications

Abstract

Non-metallic raw materials are largely unexplored in many African countries. In an attempt to reduce this knowledge gap, kaolin occurrences in three promising regions of southern Mauritania were examined. The aim of the paper is to describe the occurrences and characterize the material in terms of mineralogy and potential technical use in the ceramics industry. The kaolins are geologically associated with various sedimentary rock units in either the Coastal Basin (Kaédi), the Mauritanide Belt (Hassi Abyad) or the Taoudeni Basin (Néma). Geochemical data show Al2O3 contents of between 9% and 38% (corresponding to 23–96% kaolinite). Samples from the Hassi Abyad and Kaédi regions have greater kaolinite contents on average and were further investigated mineralogically. The kaolin from the Néma region contained less kaolinite (<50 mass%). The region is also less accessible and hence is not considered further in this study. X-ray diffraction, X-ray fluorescence and infrared spectroscopy confirmed the geochemically calculated kaolinite contents of the kaolins and identified quartz, anatase and goethite as the remaining major mineral constituents. The degree of structural disorder of the kaolinites (determined by infrared spectroscopy) is generally greater in the Kaédi occurrences than at Hassi Abyad. Ceramic tests proved that all of these kaolin raw materials might be used for the production of ceramics, and some may even be used for fine ceramics. From an economic point of view, the Hassi Abyad deposit is interesting in terms of its quality and reserves, aspects that will be addressed in detail in a follow-up study.