EFFECTS OF Na₂O and BaO ADDITIONS ON PHOSPHORUS DISTRIBUTION BETWEEN CaO-MgO-Fe_tO-SiO₂ SLAGS AND LIQUID IRON.

Experiments have been made to study the effect of Na//2O(7-13 wt%) and BaO(4wt%) additions on the phosphorus distribution between liquid iron and CaO-MgO-Fe//tO-SiO//2-P//2O//5( less than equivalent to 1 wt%) slags at 1550 degree C. The effect of Na//2O and BaO on the logarithm of the equilibrium quotient is 1. 2 and 0. 9 times as large as that of CaO. The effect of Na//2O or BaO on the activity coefficients of P//2O//5 was also studied by Turkdogan and Pearson's treatment. Activity coefficients of Fe//tO decrease with the addition of Na//2O but does not change with the addition of BaO. The dephosphorization equilibrium is discussed on the basis of the theoretical optical basicity proposed by Duffy and Ingram.