Heat-treating solids

Claim 1

PROCESS OF INDURATING IN A SHAFT FURNACE DISCRETE FLUENT BODIES OF MOIST IRON ORE FINES, WHICH COMPRISES: ESTABLISHING A GRAVITATIONALLY DESCENDING COLUMN OF PREVIOUSLY INDURATED BODIES OF OXIDIC IRON ORE FINES, SAID COLUMN CONSISTING OF TWO GAS TRAVERSABLE MASSES OF THE BODIE3S DISPOSED ONE ABOVE THE OTHER AND COMMUNICATING THROUGH AN INTERVENING PORTION OF THE COLUMN OF RESTRICTED CROSS-SECTIONAL AREA COMPARED TO THE CROSS-SECTIONAL AREAS OF SAID MASSES AND ILLADAPTED TO THE FLOW OF GAS THERETHROUGH; MAINTAINING LOWER OPEN SPACES CONTIGUOUS TO LOWER FREE SURFACES OF EACH OF SAID MASSES AND GASCOLLECTING SPACES OF SUBSTANTIAL EXTENT ABOVE AND CONTIGUOUS WITH UPPER FREE SURFACES OF SAID MASSES; CHARGING A LAYER OF INITIALLY SUBSTANTIALLY UNHEATED RAW BODIES ONTO THE TOP SURFACE OF THE UPPER MASS AND DISCHARGING A SIMILAR VOLUME OF INDURATED BODIES FRM THE BOTTOM OS THE LOWER MASS THEREBY MAINTAINING SAID COLUMN''S HEIGHT; PASSING A CURRENT OF INITIALLY SUBSTANTIALLY UNHEATED AIR THROUGH THE LOWER MASS FROM THE LOWER OPEN SPACE THEREOF TO AND THROUGH THE GAS-COLLECTING SPACE THEREOF AND INTO A COMBUSTION SPACE SPACIALLY SEPARATE FROM SAID COLUMN THEREBY EFFECTING HEAT EXCHANGE BETWEEN THE INITIALLY SUBSTANTIALLY UNHEATED AIR AND THE BODIES CONSTITUTING SAID LOWER MASS; THERMALLY ENRICHING THE AIR IN SAID COMBUSTION SPACE, BY INTRODUCING AND BURNING A FLUID COMBUSTIBLE THEREIN, TO AN INDURATION TEMPERATURE BELOW BUT APPROACHING THE INCIPIENT FUSION TEMPERATURE OF THE OXIDIC IRON ORE PARTICLES CONSTITUTING SAID BODIES; PASSING THE TERMALLY ENRICHED AIR FROM THE COMBUSION SPACE TO AND THROUGH THE UPPER MASS FROM THE LOWER OPEN SPACE THEREOF TO THE GAS-COLLECTING SPACE THEREOF THEREBY EFFECTING HEAT EXCHANGE BETWEEN THE