The use of Tunisian Barremian clay in the traditional ceramic industry: Optimization of ceramic properties

This paper shows the results of various analyses and ceramic aptitude tests made on two representative clay samples from Djebel Oust on Northwest of Tunisia. Indeed, mineralogical, geochemical, physical and ceramic properties of crude samples are studied. The crystalline phases presented in different clays are illite, kaolinite, illite–smectite mixed layers, chlorite, K-feldspar, quartz and calcite. This study reveals that an amount of silica is relatively high. The content of CaO and the iron oxide should not exceed 6%. The grain size data indicates a clay-dominated assemblage. The plasticity test shows a medium value, the firing shrinkage and the expansion are limited. These clays could be used in manufacturing of the ceramic pieces.