Phosphorus can be expected to separate preferentially from silicon melt by induction vacuum refining (IVR). In the present study, thermodynamic and kinetics of phosphorus evaporating from silicon melt has been investigated. Due to the phosphorus concentration in metallurgical grade silicon (MG-Si) being around 100 ppmw level, we believe that phosphorus vaporizes from silicon as gas species P and P-2 in the vacuum refining process. A numerical model has been developed for phosphorus separation by IVR, and the mass transfer coefficients for three possible rate limiting steps are developed. Experiments have been carried out to verify the IVR model. Such key factors as vacuum pressure, temperature, and melt geometry have been investigated by comparing the experimental data with simulation curve. The effect of vacuum pressure on phosphorus removal can be divided in three regions: independent region, sensitive region, and inert region. Temperature shows nonlinear relationship with phosphorus evaporation. The melt geometry is defined as ratio of diameter to height of melt (d/h) and it is favorable to set d/h at around 4. The numerical results agree well with experimental data. (C) 2011 Elsevier B.V. All rights reserved.