Influence of mixing/milling on sintering and technological properties of anorthite based porcelainised stoneware

The effect of mixing/milling time on sintering and technological properties of a new porcelainised stoneware body was investigated. This stoneware body is basically based on anorthite (CaO·Al2O3·2SiO2) crystals development in the microstructure and was fabricated by using wollastonite, calcined alumina, quartz, Ukrainian ball clay and some magnesia as raw materials. Laboratory scale tests were carried out starting from mixing/milling of a reference body composition for different durations (3, 12, 24, 48 and 96 h) in a ball mill. Sintering and technological properties such as density, water absorption, firing shrinkage, flexural strength of each body were measured. X-ray diffraction (XRD) and scanning electron microscopy (SEM) studies were carried out to analyse the microstructure.It was found that mixing/milling has a major effect on the particle size distribution, which in turn controls particles packing. High degree of close particle packing increases the densification by reducing the number and size of closed porosity in fired microstructure, which in turn contributes to the improvement of flexural strength.