Characterization and Application of Nigerian Clay Raw Resources for Porcelain Formulation and Manufacture

Porcelain is a ceramic material made by heating refined minerals (clay) in the form of kaolinite to high temperature in a kiln at temperatures between 1200 °C – 1400 °C thus converting ceramic body irreversibly to hard product, impermeable to water and chemicals. The use of three minerals (kaolin, feldspar and sand) from Nigeria in the formulation and production of porcelain has been investigated in this study, with kaolin bond in the formulation intended to increase the thermal strength of the product. Characterization results showed that the clay contains kaolinite (58%), quartz (15%), rutile (0.5%) and illite (15%). Sample was formulated and shaped by casting into molds and sintered at temperatures ranging from 1200 °C – 1300 °C. Characterization of porcelain specimen sintered at 1250oC showed interesting results: a density ranging from 2.16- 2.25g/cm3 ; open porosity of less than 1.03%; flexural strength above 50MPa and water absorption below 0.5%.