| 摘要 |
PURPOSE:To reduce extremely efficiently Mn ore in an industrial scale in the stage of reducing the Mn ore in a oxidation refining furnace permitting bottom blowing by combining a novel method for preliminary treatment of molten iron and treatment stage thereby desiliconizing stably the molten iron and dephosphorizing advantageously the same. CONSTITUTION:Gas and solid oxygen are simultaneously blown into the molten iron and the ratio of gaseous oxygen is adjusted to 10-50% to desiliconize the molten iron so that the Si concn. in the molten iron attains <=0.15% and the molten iron temp. attains 1,400-1,480 deg.C in a mixer car which is a vessel for transporting the molten iron between a blast furnace and converter. The molten iron after discharge of slag is fed out to a converter charging pan 4 and a free board 3 is inserted into the pan 4. A dephosphorizing agent as well as gas and solid oxygen are blown into the molten iron under said board. The ratio of the gaseous oxygen is adjusted to 10-50% and after the treatment, the P and S levels are decreased to the standard value for the product or below and in this stage the molten iron temp. after the treatment is maintained at >=1,300 deg.C. The molten iron is subjected to decarburization and Mn reduction refining by bottom blowing O2 or O2-contg. gas at >=0.08Nm<3>/ton min flow rate while adding the refining furnace Mn ore to the furnace inside. |
