Thermal analysis — including evolved gas analysis — of clay raw materials

Abstract

Thermal analysis is important for both compositional determinations of clay raw materials for ceramics and technological control of firing processes (Sladek, 1985 ). The main techniques of thermal analysis are listed in Table 1. Developments in instrumentation and computer software now allow reactions to be followed in greater detail, leading to powerful new approaches such as controlled transformation rate thermal analysis (Ortega et al., 1993 ) and closely related techniques such as stepwise isothermal analysis (Sorensen, 1992 ). In this approach, the heating or cooling programme is controlled by the rate of reactions taking place in the sample. The sample is heated at a constant rate until the reaction rate exceeds a pre-set limit, at which point the