Influence of calcite in a ceramic body on its thermophysical properties

Abstract

We study thermal expansion, mass changes, heat capacity, and thermal diffusivity and conductivity for a ceramic body with (10 and 20 mass%) and without waste calcite content, using the TDA, TG, DTA, DSC, and flash method. The measurements were performed (a) for green samples either isothermally or by a linear heating up to a temperature 600, 1,050, or 1,100 °C, depending on the measurement method; (b) at the room temperature for samples preheated at 100, 200,…, 1,100 °C. In case (a) we show that a high calcite content may double the energy consumption during the anorthite creation at 950 °C. On the other hand, calcite has a slight positive effect on the final contraction and quite substantial effect on the thermal conductivity in the range 150–550 °C, decreasing it even by 50 %. In case (b) a positive impact of calcite on the final contraction is about 10 times higher than in case (a). A clear effect of calcite on the thermal diffusivity occurs in case (b) only above 600 °C, resulting in a rather different behavior for the 10 and 20 mass% calcite content.