Effect of Cooling Methods on Clinkering and Periclase Formation of High–Magnesium Portland Clinker with Different Alumina Modulus

High–magnesium Portland cement clinker with MgO content of 6% was synthesized with chemical reagent. The effect of cooling method (i.e., furnace cooling, air cooling and liquid–nitrogen quenching) on the mineral composition, C₃S crystal type, solid solubility of MgO, and formation of periclase of high–magnesium Portland clinkers with different alumina modulus (IM) (i.e., 0.64, 1.10 and 3.00) was investigated. The samples were characterized by X-ray powder diffraction with Rietveld method, petrographic method and scanning electron microscopy. The results show that a rapid cooling can stabilize C₃S crystal into M3 type, and prevent the transformation of C₃S crystal from M3 to T3 type. And this has a little effect on the change of IM. The content of C₃S is relatively high in the clinker with a low IM and by furnace cooling, and the clinker with a high IM and by liquid–nitrogen quenching. Rapid cooling rate inhibits the crystallization of periclase, and the inhibition effect is more dominant in a low IM clinker. Clinker quenching can keep the morphology of C₃S intact, and promote periclase to turn into a fine round granule.