First Deslagging Practice of Double Slag Process for Dephosphorization

The effect of oxygen-supplying system,controlling of lance height,condition of the first deslagging on dephosphorization in 120 t top and bottom combined blown converter was studied based on plant trials using double slag process.The results show that the optimum conditions for dephosphorization are as follows:the time of blowing oxygen and blowing oxygen quantity should be controlled at between 390~420 s and 2 300~2 400 m³ respectively during the first deslagging; Phosphorus content of liquid steel at the first deslagging can be reduced to minimum 0. 032%,and maximum dephosphorization rate reached 75.57% in the industrial experiment when temperature,basicity,FeO,and P₂O₅ were 1 400~1 420℃, ≥ 2.06, ≥ 10.97% and 2.54%~3.0% respectively at the first deslagging.