Synergistic Effect of Soda-Lime-Silica Glass and Porcelain Scrap on the Vitrification Behavior of Porcelanized Stoneware Tile

Abstract

Porcelain scrap, a by-product from the table ware industry, was gradually added to a soda-lime-silica scrap-glass-containing traditional porcelanized stoneware tile body replacing sand. The effect of this addition on the vitrification and physico-mechanical properties was studied by measuring the linear shrinkage, bulk density, apparent porosity, and flexural strength of the samples heated in the temperature range 1100–1250°C. The results revealed that the presence of both glass and porcelain scrap had beneficial effects in relation to vitrification at lower temperatures and development of higher flexural strength. The improvement in strength was mainly because of the formation of well-developed needle-shaped mullite crystals and stronger pre-stress caused by the difference in thermal expansion coefficient between the glassy matrix, quartz, and mullite during the cooling process. Circumferential cracking around quartz grains was observed in quartzitic sand-containing samples. XRD studies were also carried out to determine differences in phase evolution.