Reclaiming cast iron turnings - which are dried and then dosed into induction furnace for melting under controlled conditions

摘要

Cast iron turnings or similar scrap, contaminated by iron oxide, are continuously melted by being fed down the central, top opening of a coreless induction furnace into a melt, the level of the latter being kept at max. 105% of the height of the induction coil; and the dosage of the turnings is adjusted to keep a constant melt temp. (T1) of at least 56 degrees C. above the inversion temp. (T2) of SiO2/CO. An alloy addn. contg. carbon is pref. added to the melt to replace the carbon lost during the oxidn.-redn. phase. During an interruption to the process, the turnings are pref. fed into a reservoir. If there is a breakdown in the continuous feeding of the turnings, dry turnings are pref. supplied from a reservoir. Various alloy addns. can be added to the melt. During melting, the electric power and the melt height and temp. (T1) are pref. adjusted so the amt. of O2 in the melt remains below the equilibrium Si/SiO2 amt. Method provides economical recovery of cast iron from turnings etc. obtd. in machining operations.