resumo
The aim of this study is to evaluate Tunisian Tithonian-Barremian deposits for the manufacture of ceramic tiles and pigments. Three major geological domains were sampled: the North-South axis, Central Atlas and Southern Atlas. The Tithonian clay sediments (Sidi Khalif Formation) and Barremian sands (Sidi Aich Formation) outcrop exclusively in central Tunisia. X-ray diffraction revealed a predominance of illite and kaolinite and variable amounts of quartz, dolomite and feldspars in the Tithonian clays. Their technological properties were assessed in pressed ceramic tiles after firing at different temperatures. Lab-scale tests involved determinations of porosity, bending strength and linear shrinkage, and results were compared with those of commercial tiles from Tunisia and Italy. The main constituents of the Barremian sands are quartz and K-feldspars. Lab-scale tests were carried out to produce blue Co-olivine and Co-willemite pigments. Formulations showed stability and high crystallinity after calcination at 1300 degrees C. CIELab measurements confirmed the development of interesting blue coloration by the pigments when applied in transparent and opaque glazes. Their coloring performance was similar to that of the commercial equivalents tested. (C) 2010 Elsevier B.V. All rights reserved.
palavras-chave
CLAYS; BEHAVIOR; MULLITE; BRAZIL; RICH
categoria
Chemistry; Materials Science; Mineralogy
autores
Hajjaji, W; Moussi, B; Hachani, M; Medhioub, M; Lopez-Galindo, A; Rocha, F; Labrincha, JA; Jamoussi, F
nossos autores
