Late Cretaceous and Palaeocene clays of the northern Tunisia: potential use for manufacturing clay products

Late Cretaceous and Palaeocene clay deposits of the northern Tunisia were studied for potential valorization in clay product manufacturing. To achieve this goal, physicochemical characterization based on multidisciplinary approaches including mineralogy, geochemistry and thermal analyses was carried out. Clay samples collected from the Bir M’Cherga and Tajerouine study sites have undergone chemical analysis by using atomic absorption spectroscopy. The obtained results showed that the studied samples were mainly composed of silica, alumina, calcium and iron oxide. Mineralogical analysis confirmed the results of chemical analysis; it showed the main peaks of quartz, calcite, kaolinite, smectite and illite. Those clay samples were used as natural resources for manufacturing earthenware tiles. Mixtures of clays and dolomites were prepared from the Late Cretaceous and Palaeocene clays and then heated to the desired temperature to obtain different earthenware products. Finally, the prepared clay products were tested via different geotechnical analyses. It was found that the clay percentage needed to be decreased in the starting mixture to enhance the properties of the final products. Those results also indicated that industrial application of both Late Cretaceous and Palaeocene clays of the northern Tunisia could be done, especially for manufacturing clay products.