A gas injection nozzle refractory with one or more gas injection small metal tubes buried therein has improved durability. The gas injection nozzle refractory includes a MgO—C central refractory with a small metal tube buried therein, and a MgO—C peripheral refractory surrounding the central refractory. The central refractory on a plane of the gas injection nozzle refractory has an external shape of a circle with a radius in the range of R+10 to R+150 mm concentric with a virtual circle with a minimum radius surrounding all buried small metal tubes, R mm being a radius of the virtual circle.

A tuyere comprising an inner tube including a lower section having a first diameter, an upper section having a second diameter smaller than the first diameter, and a converging transition section having a converging angle Θ from 30° to 60° connecting the lower section to the upper section, the inner tube terminating in an inner nozzle at a downstream end of the upper section; and an outer tube surrounding the inner tube so as to create an annulus there between, the outer tube including a lower section having a third diameter larger than the first diameter, an upper section having a fourth diameter smaller than the third diameter but larger than the second diameter, and a converging transition section having connecting the lower section to the upper section, the outer tube terminating in an outer nozzle at a downstream end of the upper section.

This electric furnace includes one or more upper electrodes, one or more bottom-blowing tuyeres, a mechanical stirrer equipped with an impeller, and a charging device which injects an iron oxide-containing iron raw material.

A system for melting a pelleted charge material including a furnace having a feed end configured to receive a solid pelleted charge material and a discharge end opposite the feed end configured to discharge a molten charge material and a slag, a conveyor configured to feed the pelleted charge material into the feed end of the furnace, at least one oxy-fuel burner positioned to direct heat into a melting zone near the feed end to heat and at least partially melt the pelleted charge material to form the molten charge material and slag, wherein the oxy-fuel burner uses an oxidant having at least 70% molecular oxygen, and at least one flue for exhausting burner combustion products from the furnace.

A tuyere comprising an inner tube including a lower section having a first diameter, an upper section having a second diameter smaller than the first diameter, and a converging transition section having a converging angle from 15 to 35 connecting the lower section to the upper section, the inner tube terminating in an inner nozzle at a downstream end of the upper section; and an outer tube surrounding the inner tube so as to create an annulus there between, the outer tube including a lower section having a third diameter larger than the first diameter, an upper section having a fourth diameter smaller than the third diameter but larger than the second diameter, and a converging transition section having connecting the lower section to the upper section, the outer tube terminating in an outer nozzle at a downstream end of the upper section.

A molten metal processing apparatus selected from a pump, a degasser, a flux injector, and a scrap submergence device constructed to include at least one element comprised of C/C composite.

A method of operating a BOF bottom stir tuyere having an inner nozzle surrounded by an annular nozzle, including during a hot metal pour phase and a blow phase, flowing an inert gas through both nozzles; during a tap phase, initiating a flow of a first reactant through the inner nozzle and a flow of a second reactant through the annular nozzle, and ceasing the flow of inert gas through the nozzles, wherein the first and second reactants includes fuel and oxidant, respectively, or vice-versa, such that a flame forms as the fuel and oxidant exit the tuyere; during a slag splash phase, continuing the flows of fuel and oxidant to maintain the flame; and after ending the slag splash phase and commencement of another hot metal pour phase, initiating a flow of inert gas through both nozzles and ceasing the flows of the first and second reactants.

A device includes a molten metal pump and a metal-transfer conduit. A clamp may be used to attach the metal-transfer conduit to the pump. The pump has a pump base including an indentation configured to receive the metal-transfer conduit and align the pump outlet with the transfer inlet. The pump outlet may be formed in the indentation and preferably near the center of the indentation in order to better align with the transfer inlet. As the pump operates it moves molten metal through a pump outlet that is in communication with a transfer inlet in the metal-transfer conduit. The molten metal enters the transfer inlet, moves upwards in a passage in the metal-transfer conduit, and out of a transfer outlet.

High alumina cement is produced in a submerged combustion melter, cooled and ground.

High alumina cement is produced in a submerged combustion melter, cooled and ground.