Solubility of magnesium oxide in selected cement clinker phases

The substitution of Mg into cement clinker phases has been studied by isothermal annealing, followed by X-ray diffraction, electron microscopy and analysis and infrared spectroscopy of the products. The substitution of Mg into 12CaO.7Al₂O₃ is slight, and is not enhanced by concomitant substitution of fluorine. However, the coupled substitution of Mg²⁺ + Ti⁴⁺ into the ferrite phase based on 2CaO.Fe₂O₃ and 4CaO.Al₂O₃.Fe₂O₃ is more successful. The presence in clinker batches of Ti, which preferentially concentrates in ferrite, enhances their potential to incorporate Mg.