Study of the reactivity of cement raw meal: Kinetics of lime combination during the clinkering process.

This paper addresses the kinetics of lime combination and the direct link t hat exists between the mechanism of the transformation of cement raw meal a nd the mode of heating during the calcination. Experiments performed in the laboratory revealed that the kinetics of lime combination involves two sta ges : a first stage of formation of dicalcium silicate from the lime and th e silica, followed by a second stage corresponding to the formation of tric alcium silicate from the dicalcium silicate already produced with the remai ning lime and melt in the reaction medium. By applying the theoretical mode ls of heterogeneous kinetics to experimental curves, obtained during isothe rmal and nonisothermal heating, the kinetic analyses suggest that the lime combination is controlled by volume diffusion in the grains. This reactivit y is closely connected to the mode of heating during the clinkering process .