Mass transfer of phosphorus in high-phosphorus hot-metal refining was investigated using CaO-FetO-SiO 2 slags at 1623 K. Based on a two-film theory kinetic model and experimental results, it was found that the overall mass transfer coefficient, which includes the effects of mass transfer in both the slag phase and metal phase, is in the range of 0.0047 to 0.0240 cm/s. With the addition of a small amount of fluxing agents Al2O3 or Na2 O into the slag, the overall mass transfer coefficient has an obvious increase. Silicon content in the hot metal also influences the overall mass transfer coefficient. The overall mass transfer coefficient in the lower [Si] heat is much higher than that in the higher [Si] heat. It is concluded that both fluxing agents and lower [Si] hot metal facilitate mass transfer of phosphorus in liquid phases. Furthermore, the addition of Na2 O could also prevent rephosphorization at the end of the experiment. Mass transfer of phosphorus in high-phosphorus hot-metal refining was investigated using CaO-FetO-SiO 2 slags at 1623 K. Based on a two-film theory kinetic model and experimental results, it was found that the overall mass transfer coefficient, which includes the effects of mass transfer in both the slag phase and metal phase, is in the range of 0.0047 to 0.0240 cm / s. With the addition of a small amount of fluxing agents Al2O3 or Na2 O into the slag, the overall mass transfer coefficient has an obvious increase. Silicon content in the hot metal also influences the overall mass transfer coefficient. The overall mass transfer coefficient in the lower [Si] heat is much higher than that in the higher [Si] heat. It is illustrative that both flux agents and lower [Si] hot metal to facilitate mass transfer of phosphorus in liquid phases. Furthermore, the addition of Na2 O could also prevent rephosphorization at the end of the experiment.