الملخص

Combined geology, mineralogy, and geochemical data of some Egyptian clay minerals have been proved to be a powerful tool in evaluating these clay deposits for the vitrified clay pipes industry. Representative samples underwent mineralogical and geochemical analysis involving major and trace element analyses. A geochemical study of clay deposits from the different formations in Egypt was carried out to determine the environmental deposition, provenance, chemical index of alteration, and paleo-oxygenation conditions. Mineralogical studies using X-ray diffraction analysis revealed prominent kaolinite, montmorillonite, and illite peaks; harmful accessory minerals included quartz, hematite, halite, calcite, and dolomite. The total silica content is high in Mendishia, Monkar El-Wahsh, Bahariya, Wadi Natrun, Sebaya, Gabal Hamza, and Qasr El-Sagha clay deposits while Heiz and Arish clay deposits have lower silica content. The studied clay deposits are characterized by high alumina (11.5% to 18.3%) and silica (45.6% to 60.2%) contents. The CaO and MgO are high in Heiz and Arish clay deposits which implies that carbonates are present. They are characterized by very high Fe2O3, Ba, Sr, and Zr as well as low K2O, Ni, Cu, Zn, Rb, Y, Pb, Ga, and Nb contents. The Heiz and Arish clay deposits characterized by high content of Na2O. The studied characteristics are relevant for the properties of vitrified clay pipes and that three clay deposits of (Heiz, Gabal Hamza, and Monkar El-Wahsh clay deposits) exhibit the required characteristics.