Composition and ceramic properties of ball clays for porcelain stoneware tiles manufacture in Poland

The paper presents the results of investigations of mineralogical, grain and chemical composition, and ceramic properties of 18 white-firing ball clays from five producing regions in eastern and central Europe. Relationships between the bending strength of the clay after drying and its grain size and mineralogical composition were studied. High contents of illite and illite/smectite minerals in the clay, and low crystallinity of kaolinite and illite, strongly influenced plasticity but also improved sinterability, as appropriate phase transitions of clay minerals began at lower temperatures. The clays were also highly reactive towards other components of the ceramic batches for porcelain stoneware tile production. The ball clays from the Donetsk region in Eastern Ukraine are recommended for the porcelain stoneware tile production in Poland, while the Polish, German and Czech clays may be used only as supplementary components.