This paper deals mainly with the particle size distribution of pottery clays on the market and the ways of grinding using Amakusa pottery stones which are raw materials for Arita porcelain.
The conclusions obtained are summarized as follows:
1. It is elucidated from a statistical analysis that the pottery clays on the market being prepared by stamp mill grinding and elutriation have particle size distributions obeying the Gaudin-Schuhmann distribution, irrespective of whether they are pottery clays for throwing or casting.
2. A new grinding system is proposed in which a pottery stone is ground by a roller mill and successively by a stamp mill for a period of 90 minutes. It is found that a pottery powder prepared using such a method has almost the same properties as pottery clays on the market with respect to particle size distribution and mineral composition and also has enough of the properties needed to actually make Arita porcelain.
