Effect of spray-dried powder granularity on porcelain tile properties

Porcelain tiles are a ceramic product with high technical and aesthetic performance, whose composition is formulated from a mixture of clay or kaolin, quartz and feldspar. The industrial processing of porcelain tiles consists of various stages such as wet milling, spray-drying, pressing of the spray-dried powder and firing. This paper is a study focusing on determining the influence of the industrially spray-dried powder particle size distribution on technological porcelain tile properties. Five granulometric compositions were prepared artificially with the spray-dried powder: very coarse (VC), coarse (C), medium (M), fine (F), and very fine (VF). The mixtures obtained were formed by pressing at 40 Mpa and fast fired with a maximum temperature of 1220°C in industrial conditions. The results revealed that the VF composition had better sintering properties, i.e. lower water absorption (0.084%) and porosity, and a higher bending strength (46 N/mm, 2) than the other granulometric compositions prepared as a result of a larger amount of spherical regular shaped fine granules in the composition