Mineralogy, geochemistry, origin, and potential industrial applications of kaolin deposit from Hassi Abyad, Mauritania

Abstract

The Hassi Abyad kaolin deposit is in the southern part of Mauritania, around 45 km east of the town of M'Bout. Hassi Abyad lies in the middle of the Mauritanides Shield, which consists of deformed and metamorphosed Precambrian and Paleozoic formations. Complementary geological, mineralogical, and geochemical studies have been carried out to help answer questions linked to the origin of these kaolin and to determine the potential suitability for different industrial applications. The mineralogical compositions showed that Hassi Abyad kaolin is mainly composed of kaolinite (61–96%) and other minerals such as chlorite, illite, muscovite, cronstedtite, quartz, rutile, magnetite, laumontite, and gibbsite. The average chemical composition of the kaolin samples is 35.84% Al₂O₃, 45.27% SiO₂, and 14.19% LOI. Other oxides occur in low concentrations (less than1%). The higher chemical indices of alteration CIA (99.5%) and CIW (99.6%) indicate that this kaolin deposit underwent a high degree of alteration during the process of kaolinization of the source rock. The absence of high temperature minerals such as pyrite, topaz and dickite, and the presence of high Ce + Y + La and Cr + Nb contents signifies that the development and evolution of this deposit are affiliated with supergene processes. This kaolin is derived from a lateritic material, proving that they are the source rock of this deposit. The geochemical and mineralogical characteristics indicate that Hassi Abyad kaolin is applicable in ceramics, paper, cosmetics, pharmaceutics, bricks making, and pottery.