PURPOSE: To manufacture low oxygen-contg. ferrochrome nitride by adding SiCr and FSi to primary slag obtd. by melting chrome ores and calcined ash, reducing the same and blowing granular ferrochrome and an inert gas to the molten metal.
CONSTITUTION: The chrome ores and calcined ash are charged to an electric furnace (not shown in Fig.) and are melted. The primary slag obtd. by this method is poured into a ladle 5. SiCr and FSi as a reducing agent 3 are added to the primary slag via a chute 29 from a tank 28 for a reducing agent. By this method, Cr2O3 and FeO in the primary slag are reduced to separate into molten petal 30 and slag 31. A lance 21 for blowing of powder consisting of refractories 23 is immersed into the molten metal 30 and granular ferrochrome nitride from a tank 26 is blown into the molten metal 30 together with nitriding gas 32 from a discharge port 25 of the end part of the lance 21 and is melted. After deslagging, the molten metal 30 is cast into a mold to crush the obtd. ingot. By this method, massive ferrochrome nitride having low oxygen contents and high yield of nitrogen absorption in a molten steel can be obtd.
KAWASAKI KIYOSHI
YANO YUTAKA
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