Abstract: A direct-current arc furnace has a vessel with a floor and a cover, at least two vault electrodes projecting down into the vessel through the cover, and a hearth electrode exposed in the vessel generally in the floor below the vault electrodes. A scrap-metal charge is melted in this furnace by first energizing the vault electrodes with direct-current voltage of opposite polarity while displacing them downward through the charge from an upper position spaced relatively far from the hearth electrode to a lower position spaced relatively close to the hearth electrode and thereby passing an electric current through the charge to melt the charge and form a puddle of molten metal on the floor of the vessel at the hearth electrode.

Abstract: An electric arc furnace comprising at least one pair of electrodes extending through the roof of the furnace for the creation of electric arcs between each of the electrodes and the charge to be melted, and a source for applying direct current to each of said pairs of electrodes, respectively of different polarities. Preferably the furnace contains also an electric probe extending through the bottom of the furnace to determine the potential of the molten charge and means for adjusting the vertical position of each electrode for maintaining the potential difference between each electrode and the molten charge at a predetermined value.

Abstract: A wall element for furnaces useful in all types of metallurgical furnaces but particularly in electric arc steel refining furnaces is comprised of a metallic block defining a cooling circuit in the interior thereof and a lining of refractory bricks anchored firmly to the cooled metallic block. The metallic block carries anchoring lugs projecting from the internal face of the block, each lug consisting of a foot portion and a retaining portion, which is constituted by an enlarged end of the foot portion opposite the internal face. Each refractory brick has a face adjacent the internal face of the metallic block and defining a recessed portion of a cross section matching that of a corresponding one of the anchoring lugs.