摘要
In order to reduce end phosphorus content,the smelting process and slag system of 120 t duplex process converter was studied by chemical analysis,melting experiment and Factsage thermodynamic numerical simulation.The semi-steel steelmaking temperature,the influence of w( C) to w( P) in semisteel,slag basicity and w( FeO) to w( P2O5) in slag are researched.It expounded the influence of slag system on decarburization furnace smelting,and established a basic principle and final slag composition of new slag system.The results show that w (P) increased and the effect of dephosphorization becomes worse when the temperature is over 1 360℃.The average w(P) is within 0.020% when semi-steel w(C) is during 3.0% - 3.4%.The w( P2O5 ) in slag will increase with the increasing of slag w(FeO) when the w( FeO) is below 30%,and the w( P2O5 ) changes little when w( FeO) continues to increase.The increase of slag basicity has a little impact on w( P2O5 ) in slag when the slag basicity is higher than 1.5,mainly because the low temperature restricts the effect of slag melting.After the industrial application of new slag system on decarburization converter,the phenomenon of stick lance remits to a certain extent.The average slag consumption decreases to 34.7 kg/t,and end phosphorus content keeps stable during (6 ~12) × 10-5.