Method for direct reduction using vent gas

A method for direct reduction of metal oxide-containing starting materials to produce metallized material by contact with hot reduction gas in a reduction unit that receives the reduction gas, the method comprising:

• discharging the product of the direct reduction from the reduction unit by a product discharge device;
• flushing the product discharge device with seal gas to produce vent gas, the seal gas being slow-reacting or inert with respect to reaction with the metallized material and is under a pressure which is above the pressure of the reduction gas in order, practically, to form a barrier for escape of the reduction gas;
• drawing off the vent gas from the product discharge device, the vent gas containing seal gas and carbon monoxide (CO);
• wet de-dusting the vent gas;
• and
• a) introducing, directly or indirectly, at least part of the dedusted vent gas into a combustion chamber of a catalytic reformer that produces the hot reduction gas, so that the introduced dedusted vent gas serves as an energy source during combustion for producing the reduction gas by catalytic reforming;
• or
• b) supplying at least part of the dedusted vent gas to a furnace that heats the reduction gas to serve as a component of the furnace combustion gas during combustion that heats the reduction gas, or
• c) adding at least part of the dedusted vent gas to the product gas produced by a reformer as a component of the reduction gas received by the reduction unit before the reduction gas is received by the reduction unit, or
• d) a) and b), or
• e) a) and c), or
• f) b) and c), or
• g) a), b) and c).