Preparation of porcelain from Iraqi raw materials and the effect of silica particle size on its properties
T.A. Thanoon A.B.AL-Kattan Dept. of Geology, College of Science, Univ. of Mousel
Received 28/10/1999 Accepted 12/8/2000
Porcelain of 50 % kaolin, 25 % silica and 25 % feldspar was prepared. Duekhla Kaolin and Urdhuma silica sand were used. The silca sand was crushed to 8, 13, and 19 pm mean particle size. Another material rich in silica and characterized by its ultrafine nature (5 p m average particle size) available near Mosul was used as a substitute for the silica sand in order to study the effects of silica particle sizes on porcelain properties.
The samples were formed by semidry pressing and fired at 1100- 1300°C with an interval of 50°C/hr with a soaking time of 1/2 and 1 hour. The changes on firing were followed by x-ray diffraction and measurement of shrinkage, bulk density, water absorption and bending strength. Best results were attained for mixes with fine grain sizes of silica sand (8 pm average) and the ultrafine silica rich material from Mosul fired at 1250°C for 1 hour. The low alumina and high silica content of the clay used in the mixes is the reason behind disagreement of the results with the high quality porcelain.