Solid Solution Mechanism of CO2O3 During C3S Formation

Polymorphism of tricalcium silicate were prepared by a calcination method with Ca(OH)2 and SiO2 as crude materials and Co2O3 as doping agent. The solid solution mechanism of Co2O3 during C3S formation were studied by means of chemical analysis, XRD and phase diagram analysis. The results show: according to phase analyse of CaO-CoO and CoO-SiO2, Co2O3 accelerated solid reaction of CaO-SiO2. When Co2O3 additive was less than 1.5% in mass, the content of f-CaO increased with the increase of Co2O3, and the formation rate of C3S was accelerated by Co2O3; when Co2O3 addition exceeded 1.5%, the content of f-CaO decreased with the increase of Co2O3. By the least square method and defined f-CaO, the molecular formula that Co2O3 solidified in C3S could be deduced: (Ca3-0.86x Co0.86x) (Si10.14xCo0.14x) O5 (x=0.0209).