Characterization and Use of Egyptian Nubian Sandstone in the Ceramic Tile Industry

Abstract

Egyptian ball clay quarried in the Aswan area in Upper Egypt contains up to 10% Nubian sandstone. This inclusion causes problems in clay grinding when used in ceramic industries. In the present paper, Nubian sandstone was characterized for mineralogical and chemical compositions using XRD and XRF respectively. Its grinding characteristics were then established using a laboratory ball mill where stone was ground for time periods ranging from 60 to 150 min at speeds ranging from 40 to 90 rpm. The cumulative analysis and specific surface area were determined for all samples. It was found that while an increase in either time or speed favoured higher fineness, the effect of rotating speed was more pronounced than that of grinding time. The findings were then applied to the production of ceramic tiles. It was found that crushed sandstone could be crushed and ground with ball clay without impairing the grinding characteristics of the latter or affecting the composition of the final body.