Abstract: A metallurgical vessel having an energy source and in which molten metal is contained for processing. A tuyere system is provided below the level of molten metal to permit the injection of gases, fluxes, ores, alloying additions and other materials to convert the molten metal to steel.

Abstract: A steel conversion method includes the steps of delivering a first quantity of oxygen and a surrounding sheath of hydrocarbon shielding fluid beneath the level of a quantity of molten ferrous metal or bath contained in a vessel by means of bottom tuyeres and simultaneously delivering a second quantity of oxygen to the bath from above through a top lance. The oxygen delivered through the bottom tuyeres is sufficient to promote mixing and is about 10% to 40% of the oxygen required for oxidation of impurities with the balance delivered through the top lance. An additional quantity of oxygen is delivered through the top lance to the space above the bath for post-combustion of off-gases to increase the thermal energy in the bath. Fluxes such as lime are added from above in lump form in the conventional manner or are entrained in the upper oxygen stream as required.

Abstract: A tuyere assembly for use in metallurgical vessels includes a tubular metallic tuyere housing which is cast in a book of refractory material. When the tuyere block is installed in a metallurgical vessel, a tuyere is inserted within the tubular tuyere housing and the space between the tuyere assembly and the housing sealed with a suitable refractory material. After a significant portion of the tuyere assembly has burned away during metallurgical operations, the tuyere may be withdrawn from the tuyere housing and a new tuyere substituted. Any refractory lining which has burned away in the vicinity of the new tuyere may be built up with a chemically bonded gunning mixture which sets to form a dense refractory material around the tuyere assembly.

Abstract: A tuyere assembly for use in metallurgical vessels includes a tubular metallic tuyere housing which is cast in a block of refractory material. When the tuyere block is installed in a metallurgical vessel, a tuyere is inserted within the tubular tuyere housing and the space between the tuyere assembly and the housing sealed with a suitable refractory material. After a significant portion of the tuyere assembly has burned away during metallurgical operations, the tuyere may be withdrawn from the tuyere housing and a new tuyere substituted. Any refractory lining which has burned away in the vicinity of the new tuyere may be built up with a chemically bonded gunning mixture which sets to form a dense refractory material around the tuyere assembly.

Abstract: An electric arc furnace pivotable between a first position wherein a gas delivery tuyere system is above the level of a metal charge for preheating the same and a second position wherein the tuyere system is below the level of metal charge to permit the injection of gases, fluxes, ores, alloying additions and other materials for converting a metal charge. A first furnace hood is engageable with the furnace when in its first position for positioning electrodes in the furnace and a second hood is engageable with the furnace when in its second position for withdrawing gases evolved during the gas blowing period.

Abstract: The flue gases from a steel refining furnace or vessel are delivered to a gas cleaning system in which the dust is removed and collected in slurry form. The slurry is dried and reduced to dust again after which it is delivered to a storage vessel. The dust is transported pneumatically from the storage vessel to tuyeres in the steel refining vessel and thereby injected back into the molten metal within the vessel. The dust is rich in iron oxide and contributes to the steel yield from the refining vessel.