Abstract: A vitreous silica crucible manufacturing apparatus includes a plurality of carbon electrodes configured to heat and melt raw material powder by arc discharge, and a value of a ratio R2/R1 of a diameter R2 of a front end of each of the carbon electrodes to a diameter R1 of a base end is set in a range of 0.6 to 0.8. Each carbon electrode has a diameter reduction portion formed at a front end position and reduced in diameter from a diameter R3 of a base end side to the diameter R2 of the front end. When a length of the diameter reduction portion is L1, the diameter of the front end is R2, the diameter of the base end is R1, an angle between the axis lines of the carbon electrodes is ?1, and X=(R1?R2)/2, a value of L1?(X/tan(?1/2)) is set in a range of 50 to 150 mm.

Abstract: Equipment for the treatment of loads or residues of non-ferrous metals and their alloys include a rotary furnace having a vessel with a sealed door. An electrode is introduced into the rotary furnace and is used to establish a free burning convective electric arc with the load introduced into the furnace or with the furnaces bottom wall. The equipment is assembled over a hinged base which allows elevating or lowering its rotation axis with respect to a horizontal plane.

Abstract: The electrode arrangement uses vertically oriented electrodes with side wall contacts for an electrothermic smelting furnace for aluminum production. The side wall contacts are radially moveable into the furnace to compensate for wear on the contacts. The side wall contacts can be hollow to allow a slag forming charge to be fed to the furnace.

Abstract: The invention relates to a procedure for continuous supply of heat into electrically conductive bulk goods by exploiting the electrical resistance thereof in an oven chamber with an inlet opening and a drawing-off apparatus for continuous throughput of bulk goods, wherein during the throughput of material, electrical energy in the material is conducted, and to an apparatus for continuous supply of heat into electrically conductive bulk goods by exploitation of the electrical resistance thereof, in an oven chamber (1) with an inlet opening (15) and a continuous drawing-off apparatus (9) for the bulk goods, and with at least one pair of electrodes (14, 16, 19) arranged one above the other, via which the electrical energy in the material is conducted during the continuous throughput of material.

Abstract: Apparatus for the cleaning, especially degreasing, of electrically conductive material (9), for example metal and/or ceramic turning chips and/or grinding sludges, under vacuum conditions, essentially consisting of a container (4) and at least two electrodes (4,5) which are connected to a power supply unit (8), the material (9) to be cleaned being heatable by the two electrodes (4,5) by direct passage of current.

Abstract: An anode for a direct current arc furnace is proposed, in which at least part of the area of the furnace receiving the melt is provided on the inside with an electrically conductive refractory lining, which is electrically connected to the conductor located on the outside and in which a cathode is positioned vertically above the melt. The electrically conductive lining (3, 4; 9) and/or the conductor (1, 8) have varying values with respect to their electrical characteristics in the circumferential direction relative to the vertical axis of the cathode (2; 11), so that there is a planned, asymmetrical current distribution on the furnace bottom.

Abstract: A lining for a direct-current electric-arc furnace, in which at least part of that regions of said furnace which receives the melt is provided on the inside with an electrically conductive, refractory brick lining and a ring-shaped current conductor, on its outside, constitutes the opposite pole to the upper electrode centrally extending into said surface. The entire bottom area is covered with a refractory, insulating brick lining and a brick lining of graphite bricks is applied onto that brick lining in the radially outer wall region of the furnace. Located adjacent thereto in radially inward manner is an annular zone, comprising an electrically conductive, refractory brick lining. The central bottom area above said insulating brick lining is consittuted by a monolithic ramming mass. Furthermore, the material of the wall of said furnace above said brick lining of graphite bricks largely corresponds to that of said insulating brick lining at the hearth bottom.

Abstract: The invention provides a direct current electric arc furnace which is composed of a feeding system of direct current to the furnace, a movable electrode at the roof of the furnace, and a bottom electrode attached to the bottom of the furnace at the position deviated from the center of the bottom of the furnace, the deviated distance from the center being determined by a magnetic field, generated by a current in the steel bath of the furnace, from under an arc generated by the movable electrode to the bottom electrode, which can cancel a second magnetic field generated by the current of the feeding system.

Abstract: In a direct-current electric-arc furnace, the bottom contact, that is the hearth electrode, must be insulated from the metallic shell of the furnace vessel by insulating material. For this purpose, the bottom plate carrying the bottom contact essentially forms the bottom of the furnace vessel. This bottom contact, with an insulating material, or a material which is at least a poor electrical conductor, inbetween, rests on a part, projecting radially inward, of the metallic vessel shell.

Abstract: An electric furnace comprising a container having electrically isolated wall segments useful for melting materials, particlularly ceramics, is disclosed.The electric fornace's side walls are constructed from electrically isolated segments, which cause electric current from a plasma torch to be concentrated on the material in the furnace to be melted rather than diverted to the walls of the furnace.