Hot metal dephosphorization for pre-treating agent

摘要

PURPOSE:To obtain pre-phosphorizing agent having a low m.p. and excellent dephosphorizing effect without using fluorite, etc., by mixing CaO and SiO2 with iron oxide at the specific ratio and fusing or sintering. CONSTITUTION:At the time of producing molten steel by oxygen-blowing after receiving molten iron tapped from a blast furnace and charging it into a converter, in the case of pre-dephosphorizing the molten iron in order to reduce load in the converter and oxygen consumption, the material mixing CaO and SiO2 with the iron oxide FeXOY and fusing or sintering, is used as the dephosphorizing agent. ln this case, the pre-dephosphorizing agent is made to composition having 50% T.Fe, =2 basicity shown with CaO/SiO2 and =1450 deg.C m.p. The pre-dephosphorizing agent, which is easily melted in the molten iron of comparatively low temp. and has low temp. reaction, high basicity and high oxidization, can be produce without using the raw material in high cost, such as fluorite, soda ash.