An example embodiment of the present invention provides a system for preheating ferromagnetic scrap. The system can include a preheating unit that is configured to hold ferromagnetic scrap and to receive hot gases. The preheating unit may include a removable cover that can include an electrical magnet system. The electrical magnet system can comprise an electrical magnet, a lifting device configured to lower and raise the electrical magnet, a power system configured to provide electrical power to the electrical magnet, and an electrical control system configured to operate the magnet. A hot gases cleaning system may be fluidly connected to the preheating unit.

A pipe-within-a-pipe and method of use are provided. The pipe-within-a-pipe comprises a first tube overlaying a second tube. The first tube and the second tube have different structures in some respect.

A pipe-within-a-pipe and method of use are provided. The pipe-within-a-pipe comprises a first tube overlaying a second tube. The first tube and the second tube have different structures in some respect.

A thermochemical regenerator system is operated without encountering accumulation of unwanted solids on the interior surfaces of the passages through which flue gas passes.

Thermochemical regeneration is enhanced by injecting fuel gas to entrain recycled flue gas that passes out of a regenerator to form a mixture that is impelled into the other regenerator.

A radiative recuperator preheats oxidant and/or fuel for combustion at one or more burners of a furnace. The recuperator includes a duct, at least portions of which comprise a material having a thermal conductivity of greater than 1 W/(m.Math.K), preferably greater than 3 W/(m.Math.K), that receives hot flue gas produced by the burner(s). The duct radiatively transfers heat to oxidant or fuel (for preheating) flowing through one or more metallic pipes disposed in between the duct and an insulating wall.

To directly and clearly observe the state inside a melting chamber in an electric furnace, a video-device-equipped electric furnace comprises: a melting chamber; a preheating chamber; and a video device to observe an inside of the melting chamber. The video device includes: a relay lens; an inner tube containing the relay lens and having an outer diameter of 100 mm or less; an outer tube containing the inner tube; and an imaging device located at an axial end of the relay lens on a furnace outside. The video device is provided through a hole in a furnace wall or lid so that the relay lens is located 300 mm to 3500 mm away from a highest molten iron interface in a vertically upward direction and the imaging device is located 300 mm or more away from an inner wall of the furnace wall or lid in a furnace outward direction.

The disclosure relates to a melting furnace, for example a two-chamber furnace, for the recovery of aluminum from aluminum scrap. This has a scrap chamber (2), with a dry hearth (6), the surface of which provided for receiving aluminum scrap is arranged above the surface of an aluminum melt (7) located in the scrap chamber (2) during operation of the melting furnace (1), and a heating chamber (3), which has at least one burner (9) for fuel firing, the heating chamber (3) and the scrap chamber (2) being separated from one another by a partition wall (11), the partition wall (11) having at least one opening (12) for recirculation of the aluminum melt (7) between the heating chamber (3) and the scrap chamber (2). Further, a refractory lining of the surface of the dry hearth (6) and/or a refractory lining of the inner wall of the scrap chamber (2) in the region of the dry hearth (6) have channels (18) which can be acted upon by hot gas and are designed to absorb heat from the hot gas and to release it to the aluminum scrap located on the surface of the dry hearth (6) for its thermal pretreatment.

The disclosure relates to a melting furnace, for example a two-chamber furnace, for the recovery of aluminum from aluminum scrap. This has a scrap chamber (2), with a dry hearth (6), the surface of which provided for receiving aluminum scrap is arranged above the surface of an aluminum melt (7) located in the scrap chamber (2) during operation of the melting furnace (1), and a heating chamber (3), which has at least one burner (9) for fuel firing, the heating chamber (3) and the scrap chamber (2) being separated from one another by a partition wall (11), the partition wall (11) having at least one opening (12) for recirculation of the aluminum melt (7) between the heating chamber (3) and the scrap chamber (2). Further, a refractory lining of the surface of the dry hearth (6) and/or a refractory lining of the inner wall of the scrap chamber (2) in the region of the dry hearth (6) have channels (18) which can be acted upon by hot gas and are designed to absorb heat from the hot gas and to release it to the aluminum scrap located on the surface of the dry hearth (6) for its thermal pretreatment.

A radiative recuperator preheats oxidant and/or fuel for combustion at one or more burners of a furnace. The recuperator includes a duct, at least portions of which comprise a material having a thermal conductivity of greater than 1 W/(m.Math.K), preferably greater than 3 W/(m.Math.K), that receives hot flue gas produced by the burner(s). The duct radiatively transfers heat to oxidant or fuel (for preheating) flowing through one or more metallic pipes disposed in between the duct and an insulating wall.