A blast furnace system is used wherein the coke rate is decreased by recycling upgraded top gas from the furnace back into its shaft section (which upgraded top gas is heated in a tubular heater prior to being recycled). The top gas, comprising CO, CO.sub.2 and H.sub.2, is withdrawn from the upper part of the blast furnace; cooled and cleaned of dust, water, and CO.sub.2 for increasing its reduction potential and is heated to a temperature above 850 C. before being recycled thus defining a first gas flow path used during normal operation of the blast furnace. Uniquely, a second gas flow path for continued circulation of top gas selectively through the heater and a cooler during operation interruptions of the blast furnace allows time for gradual controlled cool down of the heater in a manner to avoid heat-shock damage to the tubular heater.

An apparatus to feed and pre-heat a metal charge to a melting furnace of a steelworks comprises a feeding and pre-heating tower separate from the melting furnace provided with at least one compartment to temporarily contain said metal charge, transfer means to transfer said metal charge to said melting furnace and conveying means to convey the fumes exiting from the melting furnace to said compartment. The apparatus also comprises a post-combustion chamber, disposed adjacent to and below said compartment, and connected on one side to said compartment and on another side to said conveying means, the post-combustion chamber being configured to determine the expansion of the fumes introduced by the conveying means and to direct said expanded fumes toward said compartment along a path such as to determine a desired residence time of said fumes suitable to obtain at least the substantial complete combustion of the unburned gases present in said fumes.

A dross processing assembly includes a stirring station at which dross in a first dross recovery vessel is stirred and a pressing station at which previously stirred dross in a second dross recovery vessel is pressed simultaneously with the stirring of the dross in the first dross recovery vessel. The stirring station and the pressing station may be commonly housed in an enclosure. A conveyor system may advance dross recovery vessels through the dross processing assembly for continuous dross processing.

The invention relates to a device for heating molten metal by the use of a heater that can be immersed into the molten metal. This immersion heater includes an outer cover formed of one or more materials resistant to the molten metal in which the immersion heater is to be used, and a heating element inside of the outer cover, where the heating element is protected from contacting the molten metal.

Methods and systems for producing direct reduced iron (DRI), comprising: generating a syngas stream in a carbon dioxide (CO2) and steam reformer; and providing the syngas stream to a direct reduction (DR) shaft furnace as a reducing gas stream. The methods and systems also comprise combining the syngas stream with a recycled off-gas stream from the DR shaft furnace to form the reducing gas stream. The methods and systems further comprise removing carbon dioxide (CO2) from the recycled off-gas stream from the DR shaft furnace prior to combining it with the syngas stream to form the reducing gas stream. The methods and systems still further comprise feeding CO2 removed from the recycled off-gas stream from the DR shaft furnace to the CO2 and steam reformer. The methods and systems still further comprise feeding recycled off-gas from the recycled off-gas stream from the DR shaft furnace to the CO2 and steam reformer.

A method for venting a spray-cooled roof of a ladle metallurgical furnace is provided herein. The method begins by processing molten metal materials in a ladle metallurgical furnace having a spray-cooled roof with an opening configured for one or more electrodes to pass there through and an integrated hood. Process gases and fumes are extracted through a channel having walls disposed within an enclosed space of the spray-cooled roof. The walls of the channel are cooled with a spray-cool system extends between the walls of the channel and a top of the spray-cooled roof.

A method of using an exhaust structure includes receiving a gas at an intake section, the intake section has a first inner diameter at a first position. The method includes passing the gas from the intake section to a piping section, wherein the piping section has the first inner diameter in a central region of the piping section, and the first position is farthest from the central region. The method includes outputting the gas from an output section connected to the piping section, wherein the output section comprises a curved portion configured to change a direction of the gas, and the output section has the first inner diameter at a position of the output section farthest from the central region. The method includes resisting turbulence and condensation during propagation of the gas through the piping section using a plurality of smoothing layers on an inner diameter of the piping section.

A cooling assembly for cooling exhaust gases emitted from a steel-making furnace includes a body having a cross-sectional shape with a thickness defined between an outer surface and an inner surface thereof. The body includes a first mounting end having a first length and a second mounting end having a second length, the second length being different from the first length. The body is arcuately-shaped with a concave inner surface and convex outer surface, and the second mounting end is spaced from the first mounting end. A fluid conduit is defined between the inner surface and the surface for a cooling fluid to flow therethrough.

A shuttle kiln (100) according to certain aspects includes at least one flue channel (124) and multiple flue risers (122) in fluid communication with the flue channel (124), and at least one shuttle (104) defining multiple exhaust shafts (140) arranged above the multiple flue risers (122), wherein an aggregate volume of a first exhaust shaft/riser pair (140-1, 122-1) differs from an aggregate volume of a second exhaust shaft/riser pair (140-2, 122-2). Such configuration at least partially compensates for different backpressures that would otherwise be experienced by flue gas exiting a shuttle kiln cavity (138) through different exhaust shafts (140), thereby improving uniformity of flue gas flow and reducing temperature variability within a kiln cavity (138).

A coupling has an opening and a protrusion extending downward from the opening. The protrusion has threads that are preferably positioned outside of the opening. A rotor shaft that connects to the coupling has an internal bore with threads that receives and retains the protrusion, such as by a threaded connection between the two, so the protrusion applies driving force to the shaft.