A critique of thermokinetic analysis in solids processing: Cement industry as a case study

• Importance of thermal analysis technique in cement clinkerization.
• Problems of extensive use of thermal analysis in handling complex solid-phase reactions.
• Identified need of focused research to analyze multi-step solid phase reactions.

The study of reactive processes involving solid phases represents a considerable challenge, especially when multiple reactions are involved. The formation of cement clinker, from naturally occurring raw materials, typifies the challenges. Thermal analysis techniques have greatly accelerated the pace of research in this area. In most cases, isothermal reaction studies and use of other instrumental methods have been replaced by programmed temperature studies, facilitated by sophisticated instrumentation and data analysis packages available for thermal analysis. In this paper, we examine the consequences of such exclusive dependence on thermal methods, to plant practice on the one hand, and to fundamental investigations on the other. We do this, drawing on our recent studies on some of the sub-processes in cement manufacture. Possible artifacts which have to be guarded against in routine applications of these methods, and areas which are in urgent need of research inputs are highlighted.