The use of constant rate thermal analysis (CRTA) for controlling the texture of hematite obtained from the thermal decomposition of goethite

Constant rate thermal analysis (CRTA) has been used for studying the decomp osition of three synthetic needle-shaped goethite samples. This method cont rols the reaction temperature such that the reaction rate and partial press ure of water vapour are kept constant at a selected value. The effects of t he pressure of water vapour generated during the dehydration of goethite an d of the decomposition rate on the porosity of the resulting hematite have been studied. The effect of the particle size of the precursors on the text ure of the final products has also been analysed. By this method, acicular particles of alpha-Fe2O3 with controlled porosity oriented along the c-latt ice axis (the long axis of the particle) have been prepared.