Some embodiments described here concern a method for melting metal material in an electric arc furnace, which includes a step of loading solid metal material into the electric furnace, a step of powering the electric furnace and of generating an electric arc between at least one electrode and the metal material, and a step of melting the solid metal material to obtain molten material. Some embodiments described here concern an apparatus for melting metal material including an electric arc furnace and an electric power supply apparatus suitable to power the electric furnace.

The invention relates to a method for extracting metal from metal-containing raw material in a batch process by using a direct current electric arc furnace (100) having one or more than one top electrode (125) and at least one bottom electrode (115), wherein the method comprises the following steps: adding the metal-containing raw material to the furnace (100), thereby obtaining a loaded bath, moving the top electrode(s) (125) onto the raw material, heating the loaded bath in a heating step by applying direct current through the top electrode(s) to provide an arc to melt the raw material, thereby obtaining molten metal (202), wherein an average voltage during the heating step is from 20 V to 110 V, and forming solid metal from the molten metal (202). The invention further relates to a direct current electric arc furnace, a system comprising a direct current electric arc furnace, and a solid metal obtainable by the method.

The present invention provides an electric furnace including: a cylindrical furnace wall; a furnace cover that is provided at an upper end of the furnace wall; and a furnace bottom that is provided at a lower end of the furnace wall and includes a deep bottom portion and a shallow bottom portion as a region having a height of 150 mm to 500 mm from a deepest point of the deep bottom portion, in which a slag pouring port into which molten slag or a solidified slag lump is capable of being poured from a slag transport container directly or through a tilting trough is provided, the slag pouring port overlaps the shallow bottom portion in a plan view, and the area ratio of the shallow bottom portion to the furnace bottom in a plan view is 5% to 40%.

Magnetic field components are measured at multiple longitudinal positions and used to calculate estimated longitudinal position and length of a transversely localized electric current segment flowing across a gap between conductive bodies. The apparatus can be used with a remelting furnace. The electrode and ingot act as the conductive bodies, and arcs, discharges, or slag currents are the current segments spanning the gap. Actuators for movable sensors can be coupled to the sensors in a servomechanism arrangement to move the sensors along with the moving gap. An actuator for moving one of the conductive bodies can be coupled to sensors in a servomechanism arrangement to maintain the gap distance within a selected range as the gap moves.

A method determines the consumption of electrode material during the operation of an electric furnace, particularly an arc furnace for producing steel. The method determines a weight of an electrode column, which is arranged in the electric furnace or is to be introduced into the electric furnace, using a weighing device. A device for determining the consumption of electrode material of an electric furnace, particularly an arc furnace for producing steel, is provided for performing the method. The device contains a weighing device for determining the weight of at least one electrode column which is arranged in the electric furnace or is to be introduced into the electric furnace, wherein the weighing device is integrated in an operating device of a system containing the electric furnace. Vibration conditions of the electrode column during operation of the electric furnace can also be determined with the method and with the device.

Sensors measure magnetic field components, and the measured fields are used to calculate and estimated transverse position of a longitudinal electric current flowing as an electric discharge across a discharge gap. Based on the estimated position, and according to a selected transverse trajectory or distribution of the estimated discharge position, magnetic fields are applied transversely across the discharge gap so as to control or alter the estimated discharge position. Inventive apparatus and methods can be employed, inter alia, during operation of a vacuum arc furnace.

Magnetic field components are measured at multiple longitudinal positions and used to calculate estimated longitudinal position and length of a transversely localized electric current segment flowing across a gap between conductive bodies. The apparatus can be used with a remelting furnace. The electrode and ingot act as the conductive bodies, and arcs, discharges, or slag currents are the current segments spanning the gap. Actuators for movable sensors can be coupled to the sensors in a servomechanism arrangement to move the sensors along with the moving gap. An actuator for moving one of the conductive bodies can be coupled to sensors in a servomechanism arrangement to maintain the gap distance within a selected range as the gap moves.

Sensors measure magnetic field components, and the measured fields are used to calculate and estimated transverse position of a longitudinal electric current flowing as an electric discharge across a discharge gap. Based on the estimated position, and according to a selected transverse trajectory or distribution of the estimated discharge position, magnetic fields are applied transversely across the discharge gap so as to control or alter the estimated discharge position. Inventive apparatus and methods can be employed, inter alia, during operation of a vacuum arc furnace.

A tap on a metallurgical vessel, in particular an electric arc furnace, is provided with a refractory end brick (6) that has an outlet opening (10). There is assigned to the lower face surface (11) of the end brick (6) a slot (15) which is shaped such that with the latter a tear-off edge (16) is generated on the outlet opening (10) when emptying the vessel. This slot (15) is annular in form and is provided here with a radially outwardly inclined inclined surface (18), and this tear-off edge (16) is thus formed immediately following the outlet opening (10). Thus, after each tapping process, the tap can be cleaned without manual assistance by shearing off with the front edge of the plate of the closure device.

Multiple magnetic field sensors are arranged around a current-containing volume at multiple longitudinal and circumferential positions. Each sensor measures multiple magnetic field components and is characterized by one or more calibration parameters. A longitudinal primary current flows through two end-to-end electrical conductors that are separated by an arc gap, and flows as at least one longitudinal primary electric arc that spans the arc gap and that moves transversely within the arc gap. Estimated transverse position of the primary electric arc is calculated, based on the longitudinal position of the arc gap, and two or more of the measured magnetic field components along with one or more corresponding sensor positions or calibration parameters. In addition, estimated occurrence, position, and magnitude of a transverse secondary current (i.e., a side arc) can be calculated based on those quantities.