| 摘要 |
<p>A method and apparatus are disclosed for achieving improved reduction efficiency and thermal economy in the reduction of particulate metal ores, e.g., iron ore, in a vertical shaft, moving bed reactor. The reactor consists of a primary reduction zone, a cooling zone and a secondary reduction zone located between the primary reduction zone and the cooling zone wherein ferric carbide formed in the primary reduction zone further reduces the residual iron oxide in the presence of an inert gas at a temperature below the melting point of the sponge iron. In one embodiment of the invention the gas produced by the reaction in the secondary reduction zone is withdrawn into a combustion chamber where it is mixed with air and burned, carbon dioxide is removed from the effluent gas of the combustion chamber and the remaining inert gas is recirculated to the secondary reduction zone. In another embodiment of the invention inert gas is supplied from an external source and carbon dioxide is eliminated from the system by means of a controlled purge. Use of the disclosed secondary reduction system allows for a lower residence time of the metal ore through the reactor and increased thermal economy.</p> |
