Abstract

The sustainable use of industrial raw materials requires accurate characterization and strategic sourcing. In Portugal, the ceramic sector is economically important and depends heavily on aluminosilicate raw materials such as feldspar, kaolin, and clay. This study evaluates twelve Portuguese samples—four feldspars, four kaolins, and four clays—collected near major ceramic industry hubs in central and northern Portugal. The aim is to assess their suitability for industrial use. The characterization areas included chemical and mineralogical composition, particle size, specific surface area, skeletal density, thermal behaviour, plasticity, colour, and fusibility. The results reveal that feldspars exhibited greater compositional variability, particularly in alkali content, with lithium-bearing samples showing enhanced fluxing behaviour, whereas kaolins and clays presented more homogeneous, kaolinite-rich compositions, consistent thermal behaviour and plasticity suitable for ceramic processing. The proximity of these raw material sources to ceramic production centres reduces transportation costs and environmental impact, supporting sustainable supply chains. Overall, the findings indicate that Portuguese aluminosilicates show properties consistent with ceramic processing requirements, and may serve as local alternatives to imported raw materials, reducing dependence on imports while enhancing the sustainability, resilience, and competitiveness of the national ceramic industry. Future work should focus on the formulation and technological validation in ceramic products.

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