ABSTRACT
The study is concerned with the identification and use of local raw materilas in procelain production. It has the specific objective of using bone as main raw material. It is hoped that the result will be of benefit toward mass production of tableware. Material sampled were Feldspar and Quartz from Kwara State, Kaolin from Katsina State and Bone and Secondary Clay from Kaduna State. The sampled materials were processed by calcination to 900 C; crushing and watermilling for at least 7 hours. The clays were processed by levigation. A Rational Analysis of the previously analysed raw materials was carried out. Formulation of bodies was done via a 66-tile triaxial blend of Feldspar, Kaolin and Bone Ash. Further tests like shrinkage, porosity, modulus of rupture, slip casting and firing tests were carried out on the selected bodies. Test bodies were made up and milled for 4 hours and were cast in simple drop out moulds. Such pieces were then fired supported with calcined Kaolin and Silica sand or unsupported. Discussion and analysis of results based on physical observation were made. It was observed that Bone China slips dry fast, set fast and crack easily especially if the drying rate at the surface is not synchronised with the flocculation of the plaster mould. It was also observed that slips high in clay are a little stronger. 20% addition of both Bomo Clay and Okene Quartz, however, stained the paste and produced glassy results. Test pieces with cracks deteriorated further in firing, an evidence of the irreversible nature of casting faults of Bone China.