A Low-Cost Novel Talc-Based Opaque Glaze for Ceramic Floor Tiles

Zirconium silicate (ZrSiO₄) is widely used commercially as an opacifying agent in the ceramic tile industry. But due to the high price of ZrSiO_4, its alternatives are being discovered. In this research, a novel approach of replacing zirconium silicate with talc [Mg₃Si₄O₁₀ (OH)₂] in ceramic floor tile glaze has been investigated to make the glaze cost effective. Zirconium silicate is gradually replaced by six different weight percentages of talc in glaze compositions. All the prepared compositions were fired in a roller kiln under industrial conditions. After firing, all the samples were collected from the kiln exit and were subjected to various quality check tests like water absorption, bending strength, chemical test, thermal expansion and shrinkage. The color index for the fired samples is measured by CIELEB color space, and it is concluded that better opacity can be achieved by totally replacing zirconium silicate with talc. Resistance of the fired sample tiles to the chemicals attack is also studied, and no significant changes are observed on the surface of the sample tiles. The surface morphology of all the glazed sample tiles is analyzed by SEM and EDX. At the end, both opacifying agents, i.e., zirconium silicate and talc are economically analyzed, and it is concluded that the replacing of zirconium silicate with talc can reduce the cost of opacifier by 82%.