Iron oxide reduction

Claim 1

IN THE PROCESS OF OPERATING A BLAST FURNACE TO REDUCE IRON OXIDE WHEREIN AN OVERHEAD GAS CONTAINING ESSENTIALLY CARBON MONOXIDE AND CARBON DIOXIDE IS RECYCLED TO SAID FURNACE AFTER TREATMENT TO DECREASE SUBSTANTIALLY THE CARBON DIOXIDE CONTENT OF SAID OVERHEAD GAS, THE IMPROVEMENT WHICH COMPRISES BURNING A PORTION OF SAID OVERHEAD GAS TO PREHEAT A SECOND PORTION THEROF AND OXYGEN OF AT LEAST ABOUT 90% BY VOLUME PURITY TO A TEMPERTURE OF AT LEAST 1300* F., REACTING SOLELY THE PREHEATED PORTION OF SAID OVERHEAD GAS AND THE PREHEATED OXYGEN WITH COKE AT A TEMPERATURE OF AT LEAST 1800* F. TO PRODUCE A GASEOUS STREAM ENRICHED IN CARBON MONOXIDE, AND INTRODUCING SAID GASEOUS STREAM AND ADDITIONAL OXYGEN OF AT LEAST ABOUT 90% BY VOLUME PURITY INTO THE LOWER PART OF SAID FURNACE TO EFFECT REDUCTION OF IRON OXIDE.