Effect of Kaolin Type on Pyroplastic Deformation of Sanitaryware Porcelain Body

Abstract

Pyroplastic deformation is one of the major problems of sanitaryware production, because of high temperature firing and high amount of glassy phase and this problem can be reduced by controlling of amount of glassy and crystalline phases in the microstructure. As kaolins are the finest raw materials, they are not only the major source of reactive ingredients for crystal formation but also they play a great role in homogenity of microstructure. In this work, the effect of kaolin type and amount on the pyroplastic deformation and other physical and mechanical properties of sanitaryware porcelain body were evaluated. Both weight percent and Seger formulation approaches were used to change the amounts of kaoline of new compositions. With Seger approach which allows controlling molar ratios of oxides, more successful results were obtained according to weight percent approach. The recipe D1 was produced by using Seger formulation approach with better physical properties than standard body. D1 has 12% higher casting rate, 10 degrees C lower sintering temperature and 8% lower pyroplastic deformation value than standard body. Thus, it was found out that pyroplastic deformation and physical properties of bodies can be controlled by modification of kaolin type and amount in sanitaryware body by Seger formulation. In addition, this study shows that Seger formulation can be used an alternative method to control of the product properties in ceramic industry rather than traditional weight percent approach.