Phosphorus capacity of CaO-SiO₂-Al₂O₃-MgO-Fe_xO slag

Abstract

The CaO-SiO₂-Al₂O₃-MgO-Fe_x O slag occurs in the production process of Corex ironmaking technology. Most of its metallurgical properties, especially the phosphorus property, are different from the slag produced from blast furnace or converter. In order to explore the dephosphorization ability of CaO-SiO₂-Al₂O₃-MgO-Fe_x O slag, its phosphorus capacity was measured at 1 673 K by gas-slag-metal equilibrium technique. An iron crucible was used as the reaction vessel, Ag alloy with 0.2% P was used as the metal phase which equilibrated with CaO-SiO₂-Al₂O₃-MgO-Fe_x O slag, and a constant flow of CO-CO₂-N₂ gas was used to provide oxygen partial pressure in the experiment. The effects of MgO, Fe_x O and basicity on slag phosphorus capacity were investigated by single factor test. The results show that the phosphorus capacity rises firstly and then decreases with increasing MgO content under the condition of basicity 1. 3, Fe_x O content of 2 % and Al₂O₃ content of 12%. The phosphorus value reaches maximum as the MgO content is 8%. When the basicity of slag is 1.1, MgO content is 10%, and Al₂O₃ is 12%, the phosphorus capacity increases with the increase of Fe_x O content. The phosphorus capacity rises linearly when the basicity is increased from 1. 1 to 1. 5.