Effect of Titania on the Dehydration Kinetics of 12-( Calcium oxide )-7 -(aluminium oxide) Hydrates

Department of Chemical Technology, University of Calcutta, Calcutta-700 009

Manuscript received 7 November 1991, revised 20 November 1992, accepted 19 February 1993

12-(Calcium oxide)-7-(aluminium oxide), i.e. C₁₂A₇ is almost always present in variable proportions upto 15% in the ordinary high alumina cements and the more refactory calcium aluminate cements. The thermal stability of C₁₂A₇ hydrate in relation to titania has been studied by thermogravimetry. The dehydration rate curves obtained at different temperatures (100-400°) follow first order kinetics. The activation energy values of the dehydration reactions are found to be dependent on the titania content. A 6% titania has beneficial role on the thermal stability of the hydrated C₁₂A₇.