Behavior of Iron Oxide in the Heating Process of Bizen-clay and Potassium Chloride Mixture

Abstract

Hematite was formed when mixtures of Bizen-clay and potassium chloride were heated to temperatures between 600°C and 1100°C. Clay minerals in Bizen-clay reacted with potassium chloride to liberate iron in the form of hematite. Above 1200°C, however, no hematite was detected within the glassy phase. When the glassy phase was cooled down slowly, hematite reappeared. This reappearing hematite could be responsible for Hidasuki, the red surface coloration characteristic of Bizen-yaki.