Dephosphorization Kinetics of Hot Metal at Low Slag Basicity and Low Temperature under the Different Fe₂O₃ Addition Amounts

In this article, the influence of the Fe2O3 addition amount on the dephosphorization kinetics of hot metal at the low slag basicity (CaO/SiO2) of about 1.6 and low temperature of 1623 K is investigated with laboratorial experiments and the kinetic model. Si and P contents in the hot metal during the whole dephosphorization process, and the endpoint FeO content in the slag, show good agreements between the calculated results with the kinetic model and experimental results. The peak value of dephosphorization rate linearly increases from 8.35 x 10(-5) to 4.52 x 10(-4) mass% s(-1) when the weight ratio of Fe2O3 is increased from 5 to 10/100 g hot metal. With the increase in Fe2O3 addition amount, the mass transfer coefficient in the hot metal phase (k(m)) and that in the slag phase (k(s)) and dephosphorization rate constant (k) all increase. The value of k(m) is found to be 4.34 times that of k(s). During the dephosphorization process, the rate-controlling step converts from the mass transfer in slag phase to the mass transfer in hot metal phase in less than 10 min. With the increase in Fe2O3 addition amount, the value of interfacial oxygen activity of alpha*(O) increases from 0.0102 to 0.0201.