Mineralogical and chemical classification of Pleistocene clays from the Lucanian Basin (Southern Italy) for the use in the Italian tile industry

Abstract

Data from literature and some representative ternary diagrams from Fiori et al. (1989) have been used to point out a more suitable use of Pleistocene clays, occurring in Lucanian and Apulian areas (Southern Italy), in the Italian tile production. The clays considered consist mainly of clay minerals (illite, smectite, chlorite and kaolinite) mixed with carbonates (calcite and dolomite), quartz and feldspars, and can be used as starting materials for the production of the so-called red bodies. From bodies of Lucanian clays, poorer in carbonates, the “cotto toscano” tiles can be directly obtained and also “stoneware” ones with the addition of a little quartz and feldspar. On the other hand, in the bodies of Apulian clays, the addition of suitable amounts of quartz, feldspars and carbonates are necessary to produce “porous single-fired” and “cotto toscano” tiles. Nevertheless, further technological testing is needed to confirm the mineralogical and chemical findings.