Suitability of Tanzanian Kaolin, Quartz and Feldspar as Raw Materials for the Production of Porcelain Tiles

Abstract

Kaolin and quartz from Pugu; and feldspar from Morogoro were investigated to determine their suitability as raw materials for the production of porcelain tiles. From the mineralogical analysis, kaolin sample was found to contain kaolinite (Al2Si2O5(OH)4) and quartz (SiO2); quartz sample was found to contain only quartz mineral silica (SiO2); and feldspar sample was found to contain albite (NaAlSi3O8) and microcline (KAlSi3O8). The major chemical compounds found in kaolin and feldspar were SiO2 and Al2O3, and quartz sample was found to contain SiO2 and SO3. The tiles made from the raw materials and fired between 900 °C and 1200 °C were found to have the water absorption of 12.4 - 13.7%, bulk density of 1.89-1.95 g/cm3, apparent porosity of 24.1-26.0%, linear shrinkage of 0.0-1.7%, compressive strength of 107.4-380.4 kg/cm2 and loss on ignition of 3.6-6.0%. Among the studied compositions and firing temperatures, tiles made from a blend containing 40% kaolin, 45% feldspar and 15% quartz; and fired at 1100 °C were found to have the best properties for the production of porcelain tiles. This is an indication that the Tanzanian kaolin, quartz and feldspar are suitable raw materials for the production of porcelain tiles.