Degree of Conversion of Dehydroxylation in a Large Electroceramic Body

The initial composition (36 mass% kaolin, 30 mass% alumina, 22 mass% feldspar, 12 mass% clay) and density of a body containing kaolinite is substantially altered during dehydroxylation which starts at a temperature of ~420 °C. Values of the degree of the dehydroxylation conversion of kaolinite into metakaolinite were experimentally obtained from a cylindrical sample with a radius of 80 mm from isothermal regimes at (450, 500, 550, 600, and 650) °C with heating times from 0 h to 10 h. The degree was determined for small samples (10 × 10 × 5 mm³) from different places of the cylindrical sample. This value was calculated from the mass loss caused by dehydroxylation. The dependencies of the degree of conversion on the small sample position, temperature, and time are presented.