Thesis (M.Sc.)--Chulalongkorn University, 1999

Filter pressing, a conventional process, presently employed in the refining of local ball clays for ceramic industries, produces filter cakes with high moisture content. Practically, the consistency of the filter cakes is hard to control and, as a result, the quality of the refined local ball clay is inferior to that of the imported one, in spite of its high plasticity. This study is aimed to produce a high quality, refined ball clay by spray drying which renders low moisture content. The scope of the study covers characterization of raw materials, one local ball clay and two kaolinite clays, formulation of the recipes with respect to the imported reference (Hypure Vector clay) in terms of chemical compositions,impurities, rheological properties and working performance. The result proves that the refined ball clay is equivalent to the imported clay in green and fired properties and better in plasticity. It enhances the shaping of ceramic bodies either by casting or by other plastic forming methods. The information obtained opens the possibility of process development in a commercial scale.