| 摘要 |
PURPOSE:To adjust the content of Mn in a molten steel to a target value at a high yield of Mn and low cost by adding Mn ore as an Mn source to the molten steel and increasing the basicity of molten slag in the stage of refining for steel making by an LD converter. CONSTITUTION:The molten steel is produced by putting a molten iron into the LD converter 1, blowing oxygen thereto from a top blowing lance 2, blowing an inert gas such as Ar from a bottom nozzle 3 and subjecting the molten metal 4 to oxidation recarburization refining while stirring the same. The in expensive M ore is added to the molten metal without using costly Fe-Mn as a raw material for adjusting the content of Mn in the molten steel 4 and quicklime, dolomite, etc., are added as flux to the molten steel in such a manner that the basicity of the molten slag 5 in this stage attains >=2 to decrease the value of (Mn)/(Mn) [(Mn) is the content of Mn in the slag, (Mn) is the content of Mn in the molten steel], by which the yield of the added Mn is increased and the concn. of the Mn in the molten steel is adjusted at a low cost. |
