| 摘要 |
PURPOSE:To produce high Mn-content middle- and low-carbon ferromanganese by subjecting molten high-carbon ferromanganese to refining with a top and bottom blown converter, then charging silicone manganese and manganese oxide therein and subjecting the same to bottom blown refining. CONSTITUTION:The molten high-carbon ferromanganese which is obtd. by an electric smelting furnace, etc., and consists of about 6-7% C, about <=2% Si, about 75-85% Mn and the balance Fe is charged into a refining vessel which permits top and bottom blowing. Gaseous oxygen is top-blown to the molten metal and gaseous oxygen is blown from an inside pipe of a bottom blowing tuyere and an inert gas from an outside pipe to the molten metal. The amt. of the oxygen to be top-blown at this time is preferably adjusted to 80-97vol.%. After the molten metal is thereby decarburized to a prescribed value, the top blowing is stopped. At least one kind among silicon manganese, ferrosilicon, metal Si and metal Al and the manganese oxide are charged into the above-mentioned vessel while the bottom blowing is kept continuing in succession thereof, by which the molten metal is refined. Mn is thereby reduced from the oxide and slag and is recovered into the molten metal. The middle- and low-carbon ferromanganese contg. Mn at the ratio higher than in the original molten metal is thus obtd.
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