Iron melt of 4% C was treated with CaO based flux containing CaF2-CaCl2 and CaCl2 additives by using a rotating crucible containing 1 kg metal at 1 350°C, and the dephosphorization reaction and its important donimant factors were studied. The transport of phosphorous occurred between slag and metal.
The experimental results were explained by assuming the following equation of dephosphorization reaction :
[P]+3/2 (O2-)+5/4 O2=(PO43-)
Apparent distribution ratio, Lp(≡(P)/[P]), was strongly dependent on oxygen partial pressure, PO2, slag basicity, B, and additive contents.
Lp in air was given experimentally as follows :
B≤1.2 logLp=2.04+8.69 logB+εi·NAdd.
less than or ezualB>1.2 logLp = 2.75+εi·NAdd.
NAdd: mole fraction of additive
εCa(F, Cl)2=0.74, andεCaCl2= 2.91
Lp and overall reaction rate constant of phosphorous, kp, increased as PO2 increased.