In Portland cement clinker, calcium aluminoferrite () occurs as an "interstitial phase", crystallizing from the melt as the reaction end-product of the flux components ( and ) added in the raw materials to lower the high melting point of the oxide mix CaO-. Its presence in clinker is solely due to the need to obtain liquid at the peak kiln processing temperature (1400−1450 °C), facilitating the formation of the desired silicate phases. Apart from this benefit, its effects on cement properties are little more than those of a diluent.
In Portland cement clinker, calcium aluminoferrite (CaAlFeO4) forms as an "interstitial phase", solidifying from the melt as the result of the reaction between flux components (calcium fluoride and calcium oxide) added to the raw materials to reduce the high melting point of the oxide mixture CaO·SiO2. Its presence in clinker is necessary for achieving liquid at the peak kiln temperature (1400−1450 °C), allowing the formation of desired silicate phases. Additionally, its impact on cement properties is minimal compared to that of a diluent.