Abstract
The phosphorus reaction between molten Fe-C-P alloy([% C] = 4.4) and Li2O-CaO-SiO2-FetO slag has been investigated under the condition of mechanical stirring at 1300°C. The partial pressure of oxygen in the atmosphere and the initial concentration of FetO in the slag were varied between 0 and 0.2 atm and between 3 and 15%, respectively. The initial concentration of P in the metal was below 0.1%. In the case of rephosphorization experiment the initial concentration of P in the slag was 1.1%.
The dephosphorization rate is much affected by the initial concentration of FetO in the slag and the partial pressure of oxygen in the atmosphere, but not affected by the mechanical stirring. In the case of rephosphorization experiments the rate of rephosphorization of metal increases with increasing rotating speed of stirrer. It is found that the maximum ratio of phosphorus concentration in the slag to that in the metal ((% P)/[% P])max largely increases with increasing Fe3+/(Fe2++Fe3+) which is dependent on the partial pressure of oxygen in the atmosphere. The ratio of ((% P)/[% P])max decreases with increasing rotating speed of stirrer larger than 50 rpm. A mathematical model is developed to explain the experimental results. It is shown that the present model can interpret the simultaneous reactions between molten iron of high carbon concentration and slag containing FeO and Fe2O3.
