A proposal for the formulation of high-quality ceramic “green” materials with traditional raw materials mixed with Al-clays

Spain is one of the main ceramics producers of Europe and, in spite of the world economic crisis, the exporting market and the production of advanced ceramics are strengthening again many Spanish ceramic areas. In this sense, the efforts now should be directed to the consecution of new ceramic formulations that optimize the technological properties of the products and contribute to significant changes in the fabrication technology. Some advances should be directed to improve the drying process, to reduce the firing temperature, to eliminate efflorescence, etc., and even to reduce contamination effects of ceramic production, if possible. Accordingly, this paper presents the study of traditional raw materials, marls from the Guadalquivir Basin (south Spain) and aluminium-rich raw materials from the Badajoz province (south-western Spain) for the fabrication of structural ceramics. The investigation led to the preparation of new formulations with higher quality finished products and greater added value. The new mixtures were mineralogical (X-ray diffraction) and chemically (X-ray fluorescence) characterized and their technological properties were also determined. The obtained mixtures could be used with the existing technologies to create majolica or weakly coloured porous materials in the temperature range of 850–900 °C, but they are also advisable to be used in the fabrication of monoporosa or white/red birapida products firing at 1050 °C. In addition, as the formulations proposed contain only moderate proportions of carbonates, the CO2 emissions during firing are reduced, and the new ceramic materials would meet the requirements of “green materials” for construction.