| 摘要 |
<p>PURPOSE:To increase the reduction potential of a secondary combustion gas and making effective reutilization of the gas for preliminary reduction of iron ore by subjecting the gaseous CO generated at the time of supplying the iron ore subjected to the preliminary reduction in a preliminary reduction furnace to a melt reduction furnace and producing a molten iron to secondary combustion then supplying the same together with a reducing agent into a cyclone. CONSTITUTION:The powdery iron ore 3 and the CO-contg. gas formed by decreasing the temp. of the high-temp. reducing gas from a cyclone separator 13 to about 850 deg.C by utilizing the heat of a boiler are supplied to the preliminary reduction furnace 1 to preliminarily reduce the powdery iron ore. Such molten iron is then added into the melt reduction furnace 2. Pulverized coal 6 and oxygen 8 are supplied into the furnace 2 to thoroughly reduce the preliminarily reduced iron ore by heating and melting to form the molten iron. The CO in the reaction gas generated in this stage is burned by the oxygen 8 to increase the temp. of the molten iron and thereafter the CO is put together with hydrocarbon such as CH4 into the cyclone separator 13 to form CO+H2 and to restore the reduction potential; thereafter, the gas is utilized as the reducing gas to the furnace 1 via the boiler 18. The Fe-contg. dust emitted from the cyclone 13 is supplied to the furnace 2.</p> |
