To prevent the generation of dioxin, white fume and malodor in exhaust gas while preventing the abnormal combustion such as explosion, caused by the combustible component in the exhaust gas exhausted from a preheating chamber when cold iron is melted by using an arc melting apparatus having the shaft type preheating chamber.
The arc melting apparatus 1, which is provided with a melting chamber 2 and the shaft type preheating chamber 3 directly connected to the upper part thereof and preheats the cold iron 16 with the exhaust gas produced in the melting chamber, is used, and the cold iron is melted by supplying the arc, carbonaceous material and oxygen into the melting chamber while supplying the cold iron into the preheating chamber so that the cold iron exists in the preheating chamber and the melting chamber. When the molten iron is tapped off in the existing state of the cold iron in the melting chamber and the preheating chamber at the time when a prescribed quantity of molten iron 17 is stored, the exhaust gas flow rate in the exhaust gas flowing path 21 is increased by supplying oxygen-containing gas into the exhaust gas exhausted from the preheating chamber, and also the exhaust gas temperature is heated to a prescribed temperature and above by burning the combustible component in the exhaust gas, and thereafter, the exhaust gas is quenched.
YAMAGUCHI RYUJI
NAKAYAMA TAKESHI
MAKI TOSHIMICHI
WAKAHARA KEIJI
YAMAMOTO SHINPEI
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