Abstract: Process for the recovery of galvanized steel sheet, by remelting with substantial elimination of zinc coating, in which the remelting operation is effected in a rotating furnace (1) under the heating action of at least one flame of fuel and an oxidizing agent which is industrial oxygen. The flame is oxidizing. The furnace is provided with at least one burner (2) for the fuel and industrial oxygen, and a dust catching device (8) in the fume conduit (7) adapted to retain at least a substantial portion of the particles of zinc oxide thus produced. The burner (2) is disposed centrally in an axial end wall (3) of the furnace opposite the fume conduit (7) and the furnace (1) turns in operation about a horizontal axis.

Abstract: Temperature maintenance and metallurgical treatment furnace for a metal in liquid state, comprising a closed container for liquid metal provided with a burner of the oxygen-combustible type, a porous plug for the bottom of the container for injecting a neutral stirring gas, and openings for the introduction and/or the removal of metallurgical treatment products. The container is in the form of an insulated enclosure which is rockable about a support axis, with two ducts with vertical component, one which is in the form of a chimney opening in the enclosure close to the vault of the enclosure and serving for the introduction of liquid metal and metallurgical treatment products, the other which is in the form of a chute opening at the level of the bottom of the enclosure and in which the upper opening is in position of liquid metal removal in a rocked position of the enclosure. The burner is mounted in the vault of the enclosure.

Abstract: The process comprises the steps of mounting two rotary furnaces in series including a smelting station and a charge preheating station, effecting a smelting in the furnace at the smelting station while causing the fumes from the first furnace to pass through the furnace at the preheating station towards an exhaust chimney to preheat the charge in the preheating furnace, and transferring the furnace which is at the smelting station towards a casting station. To enable the various transfers of furnaces each furnace is associated with a transfer support including a device for causing rotation of the furnace.

Abstract: The present invention relates to a process for producing steel in a ladle furnace in which the molten steel is stirred by injection of an inert gas in the lower part of the furnace. According to the invention, the stirring of the bath of steel is effected by the injection of gaseous argon so as to distribute in a homogeneous manner the additives added and the metal temperature in the course of the treatment, while there is simultaneously injected liquid argon above the surface of the bath in the region of intumescence. In this way, substantially any increase in the concentration of nitrogen of the bath of steel in the course of the treatment is avoided. In some cases, and in particular when wires of the type filled with silico-calcium are employed, a reduction in the concentration of nitrogen in the bath of steel is found.

Abstract: Process for protecting against oxidation and/or nitridation of a liquid metal stream flowing from the outlet orifice of a ladle or a distribution vessel, comprising surrounding the pouring stream with a tube substantially throughout the height of the stream and injecting a protective gas at least around the pouring stream so as to minimize the contact of the molten metal with the ambient air and avoid the dilution of the protective gas and the aspiration of ambient air. A device for carrying out the process includes two complementary semi-shells for surrounding the pouring stream and a hinge articulating the semi-shells for opening and closing the latter.

Abstract: Process of casting steel from a ladle into a tundish, in which the metal which is in the tundish is protected against oxidation and nitridation. The process comprises two consecutive steps: a first step which includes flushing the tundish before the start of the casting of the liquid metal during which a high flow of dry ice or liquid argon is introduced until the oxygen concentration in the vicinity of the zone corresponding to the base of the jet of liquid metal at the start of the casting is lower than about 0.5%; and a second step for the upkeep of the atmosphere in the vicinity of the base of the jet which begins when the liquid metal starts to flow in the tundish, during which dry ice or liquid argon is injected as an upkeep flow which is less than the flushing flow, so as to maintain an oxygen concentration lower than about 0.5% in the vicinity of the base of the jet.

Abstract: A process for refining pig iron from below the surface of a molten metal bath, and the resulting product, in which an oxidizing gas is injected in the bath and, during the last refining stage, a mixture of oxidizing gas and inert gas is further injected. The inert gas content x of the mixture is made to vary according to a law corresponding to an oxidizing gas dilution curve that is located in an area determined by two envelope curves, to wit, a first maximum dilution curve defined by the straight line portions:x=-766.7 %C+168.7 for 0.16<%C<0.22x=-550 %C+134 for 0.1<%C<0.16x=-233 %C+102 for %C<0.1and a second minimum dilution curve defined by the straight line portions:x=-1500 %C+255 for 0.14<%C<0.17x=-400 %C+101 for 0.1<%C<0.14x=-230 %C+84 for 0.05<%C<0.1x=-72.5 for %C<0.

Abstract: A cryogenic fluid in the liquid phase is put in contact with a metal material maintained in a closed treating vessel, the cryogenic fluid which contains the solid particles formed is exhausted from the vessel, and the solid particles are separated from the cryogenic fluid and collected. The metal material is heated by induction heating with a high-frequency current and maintained in levitation in the cryogenic liquid. The process is applicable to the production of ultra-fine powders from metals which are only slightly volatile.

Abstract: The process concerns a selective refining of molten metals or alloys contained in a closed treatment container in the form of a bath 10. A solid or liquid cryogenic body 13 is brought into contact with the surface of the bath of metal 10 so as to convert, by evaporation-condensation, the vapors (vz) of the impurity or impurities to be eliminated from the bath into solid particles (pz) entrained by the vapors (vf) of the cryogenic body, and the bath of metal 10 is simultaneously stirred.

Abstract: A system for producing metal powder in which a cryogenic fluid in the liquid phase is poured over a metal bath having a vapor pressure of at least 1 mm Hg, and the solid particles suspended in the fluid are separated therefrom and collected.The particles find application in the manufacture of paints, in the treatment of rubber, and in the metallurgical, chemical pharmaceutical and ceramic industries.