Abstract: A method and apparatus is disclosed for reducing metal ore to sponge metal in a vertical shaft, moving bed, gaseous reduction reactor by controlling the amount of gas intermixing between the reduction and cooling zones of the reactor to result in increased productivity and improved carburization of sponge iron. In accordance with a preferred embodiment, process efficiency is maximized while capital cost is minimized through the use of an optimally designed reactor with a pre-determined equivalent height to equivalent diameter ratio.

Abstract: Process and apparatus for the gaseous direct reduction of iron ores wherein at least a portion of the spent reducing gas effluent from a reduction reactor is upgraded and thereafter heated and recycled to said reactor forming a reducing gas loop and make-up reducing gas is added to said loop. The hot products of combustion, i.e., flue gases, in the reformer are used to heat the recycled gas (and optionally the quenched make-up gas) while maintaining independent control of the operating conditions of the reformer and gas heater to give improved thermal efficiency and fuel savings. The reformer has a stand-by stack through which the reformer flue gas is directed when the gas heater is shut down (to permit independent continuous operation of the reformer).

Abstract: A method for the gaseous reduction of iron ore to sponge iron in a vertical moving bed reactor having a reduction zone in the upper portion thereof and a cooling zone in the lower portion thereof which comprises using a coolant gas containing up to about 30% by volume of hydrocarbon, e.g., coke oven gas, and passing a mixture of the hydrocarbon-containing gas and steam through the cooling zone to cause the sponge iron therein to catalyze the conversion of the hydrocarbon/steam mixture to carbon monoxide and hydrogen.

Abstract: A method of eliminating hot spots in a mass of sponge iron particles made by gaseous reduction of iron ore. A layer of the particulate product is moved to a separating station, near which the layer is viewed by an infra-red detector that generates a control signal when insufficiently cooled particles register therewith. The control signal is used to shift the position of a particle guide member at the separating station to cause insufficiently cooled particles to be diverted from the main particle stream. Preferably the separation is carried out in two stages. Apparatus for carrying out the method is disclosed and claimed.

Abstract: A method of using coke oven gas, and more generally gaseous mixtures containing up to about 30% by volume of methane, for the direct gaseous reduction of iron ore in a vertical shaft, moving bed reactor. In addition to the usual reduction zone and cooling zone, the reactor is provided with an intermediate reforming zone. A hot mixture of coke oven gas and steam is fed to the intermediate zone and reduced ore therein catalyzes the conversion of the methane of the coke oven gas to carbon monoxide and hydrogen. The reformed gas flows upwardly into the reduction zone of the reactor.

Abstract: An improved method for operating a blast furnace wherein a portion of the charge is prereduced iron ore with a relatively low metallization in the range of 75% to 90% and a relatively high carbon content in the range of 1.5% to 4.5% by weight. The composition of the sponge iron is selected so as to realize an increase in the production of pig iron and a decrease in the consumption of coke while simultaneously maximizing the over-all economy and efficiency of the blast furnace operation. In a preferred embodiment of the invention at least 80% by weight of the carbon content in the sponge iron used as a portion of the charge to the blast furnace is in the form of ferric carbide.

Abstract: Sponge iron is carburized in the cooling zone of a vertical shaft iron ore reduction reactor by causing a carbon-containing gas to circulate in a closed loop including the cooling zone of the reactor and an external conduit containing a quench cooler and a pump. Improved control of the carburization of the sponge iron is achieved by measuring the specific gravity of the circulating gas and using the measured specific gravity value as a control variable effectively to regulate the flow of make-up carbon-containing gas to the cooling loop.

Abstract: Improved cooling of sponge iron in the cooling reactor of a multi-stage gaseous reduction system for particulate iron ore is achieved by using a hollow foraminous closure plug at the bottom of the reactor. The plug is pivotally mounted for movement from a reactor-closing to a reactor-discharge position and has a cooling gas inlet nipple which, when the plug is in its reactor-closing position, registers with the discharge end of a cooling gas supply conduit to cause cooling gas to flow into the plug and through the wall thereof to cool the adjacent portion of the sponge iron bed within the reactor. The plug can also be used to distribute hot gas to an ore bed in a reduction reactor.

Abstract: A method and apparatus are disclosed for achieving improved reduction efficiency and thermal economy in the reduction of particulate metal ores, e.g., iron ore, in a vertical shaft, moving bed reactor. The reactor consists of a primary reduction zone, a cooling zone and a secondary reduction zone located between the primary reduction zone and the cooling zone wherein ferric carbide formed in the primary reduction zone further reduces the residual iron oxide in the presence of an inert gas at a temperature below the melting point of the sponge iron. In one embodiment of the invention the gas produced by the reaction in the secondary reduction zone is withdrawn into a combustion chamber where it is mixed with air and burned, carbon dioxide is removed from the effluent gas of the combustion chamber and the remaining inert gas is recirculated to the secondary reduction zone.

Abstract: A discharge flow regulating device for regulating the discharge of sponge metal from the bottom of a vertical, moving bed reduction reactor. A frustoconical baffle near the bottom of the reactor directs the flow of particles toward a horizontal plate spaced from the baffle and having a diameter sufficient to block the passage of the particles. Gas under pressure is supplied to the center of the plate and directed radially outward to blow particles over the rim of the plate. The supply of pressurized gas is regulated to regulate the rate at which particles are forced to and over the perimeter of the plate. The gas also serves to cool the sponge metal in the lower portion of the reactor.

Abstract: Method for rapid and accurate weight determination of molten metal in a slag-containing bath preferably without any necessity for direct gross weighings in a hostile steel works environment or otherwise, by the addition to the molten bath of a known weight amount of a "trace" element (preferably of a type which is completely diluted in the molten metal, to the practical exclusion of the slag); awaiting the even dispersal of the trace element in the molten metal (aiding the speed of dispersal by promoting a boiling action, if necessary); taking a sample of the molten metal; analyzing the sample to determine the weight percent of trace element in the molten metal (for example by spectrometric analysis); and determining the weight of the metal from the known values of weight of the trace element added and its weight percent in the molten metal after addition.

Abstract: The cooling of sponge iron produced in a multiple reactor unit batch system for reducing iron ore is enhanced by using an extended cooling cycle wherein the reactor previously isolated at the end of a cycle for discharge and recharging in prior art systems is retained on stream for a portion of the succeeding cycle.