Effect of MnO₂ on mineral coexistence in balance of portland cement clinker containg calcium sulphoaluminate

The influence of MnO₂ on the minerals formation and coexistence temperature scope in the clinker containing alite and calcium sulphoaluminate (3CaO·3Al₂O₃·CaSO₄, C₄A₃S̄) was investigated by means of quantative X-ray diffraction and chemical analysis. The results show that adding 0.1% (in mass) MnO₂ into the raw meal can speed the decomposition of CaCO₃, enhance the decomposition rate of CaCO₃, promote the solid reaction and the absorption of free lime in the process of burning, increase the liquid, accelerate the sinter of clinker, improve the decomposition temperature of C₄A₃S̄ by 100 °C, and enlarge the coexistence temperature scope between alite and C₄A₃S̄ by 57 °C.