Production of iron

Claim 1

IN THE PROCESS OF PRODUCING IRON IN THE FORM OF BRIQUETTS CAPABLE OF BEING FURTHER TREATED TO PRODUCE STEEL IN AN OPEN HEARTH FURNACE, THE STEPS OF REDUCING AN IRON ORE HAVING A SUBSTANTIAL GANGUE CONTENT IN A REDUCING ZONE, CONSTITUTED BY A ROTARY KILN, BY SUPPLYING THE ORE INTERMIXED WITH A CARBANACEOUS REDUCING MATERIAL INTO SAID KILN AND PASSING THE ORE AND CARBONACEOUS MATERIAL THERETHROUGH, WHILE MAINTAINING TEMPERATURES WITHIN SAID KILN INSUFFICIENT TO MELT THE IRON MATERIAL, BUT AT LEAST ABOUT 1700*F. AND THEREBY CARRYING OUT ALL THE REDUCING ACTION OF SAID PROCESS, PASSING THE REDUCED IRON MATERIAL FROM SAID REDUCING ZONE TO A COOLING ZONE, WHICH IS IN OPEN COMMUNICATION WITH THE INSIDE OF SAID REDUCING ZONE, BUT IS OUT OF CONTACT WITH THE ATMOSPHERE, AND HAS ITS ATMOSPHERE MAINTAINED NON-OXIDIZING SOLELY BY ITS OPEN COMMUNICATION WITH SAID REDUCING ZONE, ABSTRACTING HEAT FROM THE IRON MATERIAL IN SIAD COOLING ZONE, SO AS TO COOL IT THROUGH A TEMPERATURE RANGE INCLUDING THE RANGE FROM ABOUT 1320*F. DOWN TO A TEMPERATURE BELOW ABOUT 1200* F. AT A RATE OF NOT MORE THAN ABOUT 200*F. PER MINUTE, SO AS TO PREVENT THE TRANSITION OF ANY SUBSTANTIAL PROPORTION OF THE IRON PRESENT TO A MARTENSITE FORM, THEREAFTER FURTHER COOLING IT OUT OF CONTACT WITH AIR TO A TEMPERATURE SUFFICIENTLY LOW TO AVOID APPRECIABLE ATMOSPHERE OXIDATION, COMMINUTING THE COOLED PRODUCT AND SEPARATING THE COMMINUTED MATERIAL INTO AT LEAST ONE FRACTION CONTAINING A MAXIMUM PRACTICABLE AMOUNT OF THE REDUCED IRON PRESENT AND AT LEAST ONE OTHER FRACTION CONTAINING MOST OF THE GANGUE ORIGINALLY CONTAINED IN THE ORE AFORESAID, AND COMPACTING SAID IRON-CONTAINING FRACTION TO FORM BRIQUETTES THEREFROM WITHOUT ADDING THERETO ANY SUBSTANTIAL AMOUNT OF ANY AGGLOMERATING MATERIAL, THE BRIQUETTES SO FORMED HAVING A GREEN STRENGTH OF AT LEAST ABOUT 1000 POUNDS PER SQUARE INCH.