| Title |
Iron Redox Equilibria in Steelmaking Slag Equilibrated with Atmospheric Air |
| Abstract |
The Fe ion distribution ratio in the CaO-MgO-Fe₂O₃-FeO-SiO₂ slag was measured under the condition of equilibrium with the atmospheric air at 1873k. The effects of slag composition on the Fe ion distribution ratio were discussed and quantified. As the basicity and the MnO content in slaty increase, the Fe ion distribution ratio increases. However, The effect of iron oxide content shows to be dependant on the basicity of slag. As the iron oxide content increases, the Fe ion distribution ratio increases far the basic slag (basicity≥1.5) but decreases for acidic slag. It is revealed that the redox reaction of iron oxide in steelmaking slag is controlled by the complex anion formation reaction of iron oxide. The contents of Al₂O₃ and P₂O_5 show same effect on the Fe ion distribution ratio as SiO₂ content. The equations obtained by analyzing the effect of slag compositions influencing the Fe ion distribution ratio are as follows; ·log(Fe^(2+)/Fe^(3+)) ＝ -0.0275 F^2_1 ＋ 0.403 F₁ － 2.249 [F₁≡20N_(CaO) ＋ 7N_(MgO) ＋ 66N_(MnO)] ·log(Fe^(2+)/Fe^(3+)) ＝ -0.0258 F^2_2 ＋ 0.374 F₂ － 2.140 [F₂≡20N_(CaO) ＋ 5N_(MgO) ＋ 3N_(Fe_2O_3) ＋ 68N_(MnO)] ·log(Fe^(2+)/Fe^(3+)) ＝ -0.000649 F^2_3 ＋ 0.0212 F₃ － 0.916 [F₃≡(%CaO) ＋ 4(%MnO) ·log(Fe^(2+)/Fe^(3+)) ＝ -0.00107 F^2_4 ＋ 0.721 F₄ － 1.982 [F₄≡(%CaO) ＋ 0.38(%Fe₂O₃ ＋ %FeO) ＋ 3.2(%MnO)] |