A metallurgical melting vessel has a vertical shaft, surrounded by a housing wall, which receives steel scrap. At least one closure element, having laterally spaced-apart fingers extending parallel to one another, is mounted such that it can move between a closed position and an open position. In the closed position, the fingers protrude at least partially into the shaft for the purpose of holding back steel scrap. In the open position, the fingers free the shaft at least to such an extent that the steel scrap can fall from the shaft into the melting vessel. The at least one closure element is mounted so as to be movable from the side of the shaft into the shaft and laterally thereoutof.

Provided are a fixed-type electric furnace enabling continuous operation which allows melting without the interruption of power supply and tapping in a fixed state, and a fixed-type electric furnace and a molten steel production method using same. The fixed-type electric furnace comprises: a preheating furnace which is disposed on the side of a melting furnace and preheats an iron source (scrap) using exhaust gas from the melting furnace; a supply means for supplying the iron source, which has been preheated in the preheating furnace, to the melting furnace; the melting furnace comprising electrodes for melting the preheated iron source; and a fixed-type discharge means for discharging molten steel which has been melted in the melting furnace, wherein the preheating furnace is integrally connected to the melting furnace.

Apparatus for pre-heating and conveying a metal charge to a container of a melting plant, comprising at least a conveyor channel along which said metal charge is able to advance so as to be delivered to the container, and in which above said conveyor channel at least a hood is disposed which defines a tunnel inside which at least part of the fumes exiting from said container are able to advance. At least a zone of the hood comprises an expansion chamber located above at least a portion of said metal charge, and able to expand and keep said fumes inside it for a minimum desired time of at least 1.5 seconds before they go into contact with the metal charge.

A furnace system includes a furnace and a preheater configured to preheat material before it enters the furnace. The system further includes a duct system including a mixing chamber disposed between the furnace and preheater. The duct system further includes an exhaust duct in fluid communication with an exhaust fluid outlet of the furnace and configured to vent fluid exhausted from the furnace. The exhaust duct is in fluid communication with the mixing chamber and configured to redirect a portion of the fluid exhausted from the furnace to the mixing chamber. The duct system further includes a preheater duct in fluid communication with the mixing chamber and a fluid inlet of the preheater and configured to direct fluid from the mixing chamber to the preheater. The system further includes a duct scraper configured for movement within the mixing chamber to move particulates from the mixing chamber into the exhaust duct.

A process and a plant for preheating a metal charge fed in continuous to an electric melting furnace through a preheating tunnel provided with a horizontal conveyor, wherein the metal charge is hit, in countercurrent, by the exhaust fumes or gas leaving the electric melting furnace and by jets of gas ejected through a plurality of nozzles positioned on the hood of the tunnel. The nozzles are arranged in groups interspaced from each other in a longitudinal direction with respect to the tunnel, and generate a small-scale turbulence or inject small fast gas jets that can penetrate the main gas stream passing through the preheating tunnel, and simultaneously generate a horseshoe vortex structure composed of a descending central gas flow (downwash), and ascending flows (upwash) close to the side walls of the preheating tunnel, which enable a desired circulation of the gases.

Plant for melting metal materials comprising at least a heating unit (11) provided with a container (13) to contain the mainly metal materials and with at least an induction heating device (22) configured to heat the mainly metal materials contained in the container (13). The plant also comprises a transfer unit (25) disposed downstream of the heating unit (11) and configured to move, substantially continuously, the mainly metal solid materials exiting from the heating unit (11) to a melting furnace (12). The container (13) is provided with an aperture (16) through which the mainly metal material, heated and in a solid state, is discharged onto the transfer unit (25), and opening/closing members (17) are associated with the aperture (16), commanded by an actuator (19) and configured to open, close and choke the aperture (16) in order to regulate the delivery of the metal materials that is discharged onto the transfer unit (25).

Apparatus to heat and transfer mainly metal materials to a melting furnace (12), the apparatus comprising a transporter device (13) configured to move the materials continuously to the melting furnace (12), and at least an induction heating unit (28) associated with the transporter device (13) and configured to heat by electromagnetic induction the materials moved in the transporter device (13), keeping them in a solid state.

A process for heating a metal feedstock (31) fed in continuous to a smelting furnace (30) through a second horizontal heating section (34) through which hot discharge fumes collected from said furnace (30) pass, said fumes exerting a heating phase of said feedstock (31), characterized in that, immediately before entering said second heating section (34), the feedstock (31) is subjected to a preheating phase by heating means other than the discharge fumes collected from the smelting furnace (30). In a plant for the embodiment of said process, said different heating means are envisaged inside a first preheating section (33), which is operatively connected with said second heating section (34) by means of an intermediate fume evacuation section (35), the fumes coming from said sections (33) and (34) being conveyed to said section. Said sections (33, 34) preferably have a tunnel configuration.

An apparatus to move and preheat metal material (M) to be fed to a container comprises a containing structure, having an internal compartment and provided with a support wall, a conveyor for the material (M), a fume transit section whose volume reduces as it is distanced from said container along the longitudinal development of said containing structure, and a collector for hot fumes (F) whose volume increases in a manner correlated to said reduction in the fume transit section. The collector is located below said conveyor inside the internal compartment essentially along the entire longitudinal development of said containing structure. Moreover, one or more through apertures are made in said support wall to put the conveyor and the collector into fluidic connection.

Apparatus for continuously conveying and pre-heating a metal charge inside a container of a melting plant, includes at least a channel for conveying the metal charge, at least a hood disposed above the conveyor channel defining a tunnel and/or an expansion chamber, inside which at least part of the fumes exiting from the container advance, and apertures made in cooperation with lateral walls of the conveyor channel to discharge the fumes. The conveyor channel includes an activator that divert the fumes and/or delimit the zone occupied by the metal charge of the conveyor channel, and that cooperate longitudinally with at least part of the conveyor channel.