Dephosphorization in New Double Slag Converter Steelmaking Process with High‐Temperature Laboratorial Experiments

Abstract

The dephosphorization of hot metal with low basicity slag at 1623 K is investigated for new double slag converter steelmaking process (NDSP) using high‐temperature laboratorial experiments. When the dephosphorization time is 15 min, the dephosphorization ratio reaches the highest value of 83.2%. When the dephosphorization times are 3 and 6 min, the main phases of dephosphorization slag are black phosphorus(P)‐rich phase and white Fe‐rich phase. When the dephosphorization times are 9, 12, and 15 min, the main phases are the P‐rich phase, the Fe‐rich phase, and the matrix phase. When the dephosphorization time is 18 min, the main phases are the Fe‐rich phase, the matrix phase, and spinel phase containing MgO and Al2O3, but without the P‐rich phase. With increasing the dephosphorization time, the area fraction of the Fe‐rich phase in slag is continuously decreased and the area fraction of matrix phase is increased. The area fraction of the P‐rich phase is first increased, then decreased until it is disappeared, due to its dissolution into the matrix phase at the low basicity of about 1.4.