Method for producing sponge iron

Claim 1

IN A METHOD OF REDUCING IRON ORE TO PRODUCE SPONGE IRON IN A MULTIPLE UNIT REACTOR SYSTEM OF THE TYPE IN WHICH SEPARATE BODIES OF FERROUS MATERIAL ARE SIMULTANEOUSLY TREATED IN THE SEVERAL REACTORS OF SAID SYSTEM, AND IN WHICH AT LEAST ONE OF SAID REACTORS IS MAINTAINED AT A REDUCTION STAGE IN WHICH THE ORE IS CONTACTED WITH HOT CARBON CONTAINING REDUCING GAS AND AT LEAST ONE OF SAID REACTORS IS MAINTAINED AT A COOLING STAGE IN WHICH THE REDUCED ORE IS COOLED, SAID METHOD BVEING OF THE TYPE IN WHICH CARBON CONTAINING REDUCING GAS FROM A SOURCE OF GAS FLOWS THROUGH THE BODY OF FERROUS MATERIAL IN A REACTOR AT SAID COOLING STAGE AND THEREAFTER THROUGH A BODY OF FERROUS MATERIAL IN A REACTOR AT SAID REDUCING STAGE, THE IMPROVEMENT WHICH COMPRISES COOLING THE BODY OF FERROUS MATERIAL AT SAID COOLING STAGE IN TWO SEQUENTIAL STEPS, IN THE FIRST OF WHICH STEPS SAID REDUCING GAS IS PASSED THROUGH THE BODY OF FERROUS MATERIAL IN SAID COOLING STAGE REACTOR AT ESSENTIALLY THE SAME RATE AS SAID GAS IS FED TO THE BODY OF FERROUS MATERIAL IN SAID REDUCING STAGE REACTOR AND IN THE SECOND OF WHICH STEPS A PORTION OF THE REDUCING GAS LEAVING THE BODY OF FERROUS MATERIAL IN SAID COOLING STAGE REACTOR IS COOLED AND RECIRCULATED TO THE COOLING STAGE REACTOR TO ACCELERATE THE COOLING OF THE BODY OF FERROUS MATERIAL AT SAID COOLING STAGE DURING THE LATTER PART OF THE COOLING CYCLE.