Development of Cordierite Based Carrier Refractory Sagar Bodies for Bone Porcelain Firing Process

Abstract

During the firing process of porcelain tableware; Biscuit firing takes place at low temperatures (980-1000°C), while glazed firing takes place at high temperatures (1250-1280°C for soft porcelain, 1350-1380°C for hard porcelain). Biscuit firing in bone porcelain products, which is in the soft porcelain class, is done at higher temperatures than glazed firings. Due to the presence of bone ash in the Bone China recipe formulation, it causes the bodies to undergo vitrification in a narrow range and thus the final product to deform during sintering. Bone porcelain products are fired on carrier refractories called sagar so that they do not deform during sintering. Sagars are designed to support that model for each product model and do not shrink or deform during firing thanks to its low thermal expansion coefficient. In this study, a refractory body with a porous structure with the code of "PS1-Std" was developed by performing the characterization analyzes of refractory products with different technical properties supplied from different companies. In order to improve the mechanical properties by changing the ratios of talc, alumina, quartz and zircon in the recipe composition; A refractory product containing 8.47% zircon in its recipe composition and containing indialite, corundum, mullite, quartz and zircon phases after sintering has been developed. The microstructure images of the developed refractory product were examined with the support of SEM analysis. It has been observed that refractory products obtained as a result of recipe development studies offer a 10% longer service life than equivalent refractory products.