Kinetics of alite formation and ye’elimite decomposition in alite-ye’elimite cement clinker

Alite-ye'elimite cement (ACSA) was synthesized by single firing process at lower temperature with addition of phosphorous slag and copper slag, which could be a promising low-energy Portland cement. The coexistence of alite and ye’elimite in this clinker can improve the cement quality and their coproduction during clinkering is crucial. Thus, in order to modify the mineralogical phase composition and its chemical industrial process during the clinker sintering, the kinetics of alite formation and ye’elimite decomposition processes were studied by XRD Rietveld refinement method in this work. Results showed that, during the alite formation and Ye’elimite decomposition processes, Ginstling-Brounshtein diffusion model can be employed to determine their apparent activation energy. The activation energy of ye'elimite decomposition with temperature lower and higher than 1275 °C are 230.4 kJ/mol and 998.9 kJ/mol, respectively. The activation energy of alite formation is temperature dependent in a piecewise function divided by 1278.5 °C. The key to make alite and ye’elimite better coexisted in cement production could be controlling the acquisition of CaO during alite formation and hindering the diffusion of CaO to contact with Ye’elimite during decomposition.