Distribution Behaviors of Phosphorus in CaO–SiO₂–FeO_<i>x</i>–MgO–MnO–Al₂O₃ Basic Oxygen Furnace Slags

Considering the dephosphorization and the reuse of ladle slag in basic oxygen furnace (BOF), the distribution behaviors of P in the CaO–SiO 2 –FeO x –MgO–MnO–(0–10%)Al 2 O 3 –5%P 2 O 5 system slags are investigated in laboratory. It is found that three phases generally present in the slags, namely P‐rich phase (2CaO·SiO 2 –3CaO·P 2 O 5 ), (Fe, Mn, Mg)O phase, and liquid phase, and most of Al 2 O 3 is distributed in the liquid phase. Al 2 O 3 and FeO x reduce the areal fraction of the P‐rich phase, and the P 2 O 5 content in the P‐rich phase generally increases (up to 14.3%). Higher slag basicity results in a higher fraction of P‐rich phase and a lower P distribution ratio between the liquid phase and the P‐rich phase. Proper FeO x and Al 2 O 3 contents can not only result in the largest distribution of P 2 O 5 in the P‐rich phase but also have good slag properties, while the increase in FeO x and Al 2 O 3 contents reduces the phosphate capacity. To save cost, a higher‐basicity slag with a lower FeO x content and a certain Al 2 O 3 content can be considered at dephosphorization stage of BOF.