Abstract
The rate of dephosphorization of liquid iron by slag was investigated by measuring the change of phosphorus content of metal under CaO-FeO-SiO2 slag in a magnesia crucible. Experiments were done with slags of basicity from 0.64 to 1.70 at temperatures from 1540 to 1680°C.
The dephosphorizing reaction proceeded so fast that the equilibrium between metal and slag nearly attained after about 10min.
The experimental results could be interpreted by the rate equation derived from the assumption that the reaction rate was controlled by the transfer of phosphorus in the boundary layer of slag, while the driving force varied during a run.
The effect of slag composition on the reaction rate appeared more clearly in the change of the driving force than in the change of the mass transfer coefficient. Temperature had only a little effect on the reaction rate, because the driving force decreased with temperature while the mass transfer coefficient increased.
