Development in smelting reduction processes

Abstract

Corex process is a smelting reduction process to produce hot metal of blast‐furnace quality. Coal is used instead of coke, and this replacement makes production costs of hot metal decrease. Iron ore reduction and melting is separated into two steps: in a melter gasifier reducing gas is generated and melting energy is produced by coal gasification; iron ore is reduced in a shaft furnace. Due to this separation, a great variety of untreated coals can be used.The Corex process is designed to operate under elevated pressure, up to 5 bar. Reducing gas is generated in a fluidized bed by partial oxidation of coal. After leaving the melter gasifier, the gas is mixed with cooling gas to obtain a temperature suitable for direct reduction, i.e. approximately 850–900°C.The fines captured in a hot cyclone are re‐injected into the gasifier. Reducing gas is fed into the reduction furnace and ascends through the iron burden according to the counterflow principle. The hot DRI having a temperature of 800–900°C is continuously charged into the melter gasifier, where further reduction is effected and melting occurs. Hot metal and slag drop to the bottom of the melter‐gasifier. Analogous to blast‐furnace practice hot metal and slag are discharged by conventional tapping.