Talc in Ceramic Tile Industry

Ceramic Tile Industry

Tile is a piece of artificial stone that has different lengths and widths and its thickness is a few millimeters. One side of tile has a glass surface and is completely smooth and polished. Tile is earthenware and ceramic product which has a dramatic role in building construction and used in bathrooms, toilets, kitchens and public water dispensers and the like. Tiles are used for interior and exterior decoration as well as for sanitation and moisture insulation purposes. 21% of the world talc is used in production of ceramics. Talc has a suitable melting point, thermal expansion coefficient and a good diffusion coefficient and this properties decrease ceramic cooking temperature. Due to the high thermal conductivity, high dielectric strength and low electrical conductivity and low cost of talcs, they are used in the production of special types of ceramic and porcelain. Talc powder is mainly used as low-cost filler in tiles production.
One of advantageous properties of talc in the ceramic tile industry is its resistance against high temperature and acids, its low volume change in the wide range of heat and its great transparency. The presence of talc in ceramics creates resistance in products. Since talc prevents from formation of small cracks at cook time, as well as breaking over time, its use in this industry is more welcomed. Talc is used in glazing when silica and magnesium are required. In low grades about 4% of talc is used as a smelting aid and in high grades as refractory and heat shock resistance regulating agent.
One of the important criteria for evaluating building ceramics is their ability for water absorption. Water absorption in ceramics reduces the beauty and causes separation of glaze from the tile. The amount of porosity in the structure of the engobe and the tile is one of the effective factors in absorbing tile water. The presence of cavities and capillary channels makes it possible to transfer water to the surface of tiles and ceramics. Therefore, one of the appropriate ways to improve and control the absorption of water is to change the engobe and also to add fluxes, which is used by adding talc to three ferrite.
Experiments such as measurement of water absorption percentage, flexural strength, percentage of contractions and colorimetry were performed. The results show that by changing the ferrite composition, the water absorption as well as the whiteness of the glaze surface has changed. Samples prepared by electron microscopy (SEM) have been evaluated. Microscopic images of the specimens show that by adding talc, the engobe particles are stuck to each other and the water penetration is reduced.