Potentiality of clay raw materials from Gram area (Northern Tunisia) in the ceramic industry

• The kaolinic–illitic clays from Gram area with high quartz content have been studied.
• Chemistry, mineralogy and technological properties were investigated.
• High amount of quartz explains the absence of defects due to drying.
• Their technical and chemical properties allow them suitable for ceramic products.

The geological study of Miocene clays from Gram area, North West of Tunisia shows an important series of clay materials to use them in the faience ceramic. Selected samples were studied with the objective of analyzing their chemical and mineralogical composition, morphology, particle size, plasticity, thermal analysis and their ceramic aptitude to be used in the faience ceramic. Raw materials are mainly composed of illite and kaolinite are the dominant clay minerals with minor quartz and dolomite.The plasticity indexes are lower than 15.40%, suggesting that these clays are not plastic. Technical characterization was carried out on one representative mixture of Miocene clay samples. The firing characteristics (shrinkage and water absorption) were measured. The optimum firing temperature of clay mixture (M) has been established. These clays could be used in the manufacture of ceramic pieces.