Abstract: A solids feed means for a direct smelting plant is disclosed. The solids feed means includes 2 or more pairs of lances for injecting solid feed materials for a direct smelting process into a direct smelting vessel. The solids feed means also includes a main supply line and a pair of branch lines for supplying solid feed material to the lances of each pair of lances with the branch lines interconnecting the main supply line and the lances of the pair of lances. The lances are arranged around the vessel in pairs of diametrically opposed lances. At least one pair of lances is provided for injecting metalliferous feed material (such as iron-containing materials, particularly iron ore fines) and at least one of the other pairs of lances is provided for injecting solid carbonaceous material (such as coal) and optionally fluxes. The pairs of lances are arranged around the vessel so that adjacent lances are lances that are provided to inject different materials.

Abstract: The invention relates to a molding composition for producing insulating or exothermic feeders and other filling funnels and feeding elements for casting molds, which comprises at least: at least 10% by weight of a porous refractory material which has a continuous open pore structure; a binder for curing the molding mixture; if appropriate, a refractory filler; a proportion of a reactive aluminum oxide having a specific surface area of at least about 0.5 m2/g and an average particle diameter (D50) of from about 0.5 to 8 ?m. The invention further relates to a process for producing a feeder and other filling funnel or feeding elements for casting molds; feeders, filling funnels or feeding elements for casting molds which are obtained by the process and also their use for producing metal castings. The feeders and further shaped bodies for the foundry industry obtained from the molding composition of the invention have a particularly high gas permeability and a low density.

Abstract: A vertical shaft melting furnace is operated in a method that includes firing a plurality of burners to generate combustion products, and directing jets of the combustion products into the shaft in a bottom region of the shaft. The method further includes directing a jet of hot gas into the shaft in an upper region of the shaft in a non-radial direction, whereby the jet of hot gas can induce a swirl to disperse a concentrated channel of combustion products rising from the bottom region to the upper region through a void in unmelted portions of a load of metal pieces in the shaft. The jet of hot gas directed into the upper region of the shaft can include recirculated flue gas, a mixture of air and recirculated flue gas, or combustion products that are generated by a burner. If the jet of hot gas includes combustion products that are generated by a burner, the burner is a secondary burner that preferably is fired into the shaft with a relatively low heat input.

Abstract: The invention provides an apparatus for measuring the temperature of a molten bath comprising a) a refractory mounting sleeve (1,1?) having an outer surface (2) for contacting the molten bath and an inner cavity (3), said inner cavity having an inner surface (4), an outer opening (6) and an inner closed end (5); and b) an optical pyrometer (7) attached to the mounting sleeve and adapted to measure the thermal radiation emitted by a measurement zone (10) located inside the inner cavity of the mounting sleeve and under the molten bath level. The inner cavity outer opening (6) is adapted to receive fixedly the optical pyrometer (7). The apparatus is characterized in that the mounting plate (8) is adapted to engage in a complementary recess located at the inner cavity outer opening (6) of the mounting sleeve (1,1?). Thereby, the accuracy and reproducibility of the measure is greatly increased.

Abstract: A tuyere assembly for directing air and one or more fluid hydrocarbons into a cavity in a blast furnace. The tuyere assembly includes a blowpipe portion with a conduit defining a bore through which the air is directed. The tuyere assembly also includes a tuyere with a chamber defined by one or more walls thereof, the chamber being in fluid communication with the cavity of the blast furnace, and the chamber of the tuyere and the bore of the blowpipe portion form an internal cavity of the tuyere assembly. Also, the tuyere assembly includes one or more injector subassemblies having one or more outlet ends, each outlet end being adapted for directing the hydrocarbon into the internal cavity for combustion thereof to provide a flame substantially having a preselected flame configuration.

Abstract: A powder body melting burner which injects a powder body, fuel and oxygen into a furnace individually from a burner head and melts the powder body in flames in which the fuel is burned under oxygen support. The burner includes a single powder body injection hole provided in the center of the burner head, a plurality of fuel injection holes disposed at a predetermined central angle in the radial direction centered on the powder body injection hole, a single primary oxygen injection bole provided concentrically which each of the fuel injection holes, a plurality of second oxygen injection holes ranged in large numbers at a predetermined interval so as to enclose each of the powder injection boles and the fuel injection holes with the plurality of secondary oxygen injection holes forming a ring shape as a whole and a cooling chamber provided on the back side of the burner head.

Abstract: The invention relates to a refractory ceramic gas bubbling element for a metallurgical crucible and to a corresponding gas bubbling system comprising such a gas bubbling element.

Abstract: Liquid metal is continuously recovered by condensing metal vapour in a sealed system, more or less at atmospheric pressure, and collecting liquid metal in a crucible. The contents of the crucible are agitated and the temperature is controlled to prevent the liquid metal from solidifying. Liquid metal and dross are tapped from the crucible.

Abstract: The invention relates to an injection device for the reliable introduction of a fluid into a metallurgical vessel having a refractory lining, the device being removably insertable in the lining; comprising a refractory first body (2) and a refractory second body (3) fittingly assembled, the first body (2) being made of a refractory material less permeable to the fluid than the material of the second body (3), the first and second bodies having each a surface (4, 5) adapted to contact molten metal; and having each fluid passages (6, 7) extending from fluid feeding means (8) to a surface (4, 5) adapted to contact molten metal, the relative flow resistance of the fluid passages (7) in the second body (4) being higher than that of the fluid passages (6) in the first body (2), the fluid passages (6) in the first body (2) being constituted of slots or bores. According to the invention, the fluid passages (6) in the first body (2) are independent from the fluid passages (7) in the second body (3).

Abstract: A tuyere cooling system which includes a coolant circuit for a body section and nose section. A valve is operable to connect the coolant circuits in series or to disconnect flows to the nose section of the tuyere so that if the nose of the tuyere tears during operation, the flow of coolant to the nose section of the tuyere may be cut off without affecting the overall operation of the blast furnace.

Abstract: A method for the production of a layered metal slab by casting, which strip contains a central layer (2) and surface layers (3) on either side of it. The central layer (2) is introduced as a strip through a mould (4), into which is introduced molten metal (5), the mould (4) is cooled, whereupon a layered structure (1) is formed as the metal solidifies.

Abstract: A system for generating mechanical waves for use in smelting and conversion processes that occur in furnaces and converters for a higher production of refined metals, consisting in an electrical signal generator, transducers that convert said electrical signals in mechanical waves placed on the outer end of air blowing tuyeres and a coupling means between said system and the shell of the converter. The air blowing tuyeres are placed forming an angle less than or equal to 90° with the transducer and the airflow entrance to the interior of the converter, forming a figure with an &agr; angle shape; and the transducer is placed in the direction of the cross axis of the converter pointing towards the &agr; angle of the air blowing tuyere, for applying mechanical waves that travel in a longitudinal direction with the airflow into the converter.

Abstract: A system for generating mechanical waves for use in smelting and conversion processes that occur in furnaces and converters for a higher production of refined metals, consisting in an electrical signal generator, transducers that convert said electrical signals in mechanical waves placed on the outer end of air blowing tuyeres and a coupling means between said system and the shell of the converter. The air blowing tuyeres are placed forming an 180° angle in the direction of the airflow entrance, while the transducers are placed transversally to the air blowing tuyeres so as to apply mechanical waves that travel in a transversal direction with the air flow into the converter or pyrometallurgical furnace.

Abstract: A system for eliminating the formation of accretions inside the air blowing tuyeres of converters and pyrometallurgical furnaces in smelting and conversion processes consisting in an electrical signal generator, transducers that convert said electrical signals in mechanical waves placed on the outer end of air blowing tuyeres, coupling means between said system and the shell of the converter, air blowing means placed with the transducers to apply mechanical waves with the airflow into said converter or pyrometallurgical furnace, breaking and eliminating the accretions that form in said air blowing tuyere due to the field of mechanical waves that allows a higher reaction efficiency of the injected air, increasing the kinetics of chemical reactions.

Abstract: A system for generating mechanical waves for use in smelting and conversion processes that occur in furnaces and converters for a higher production of refined metals, consisting in a electrical signal generator, transducers that convert said electrical signals in mechanical waves placed on the outer end of air blowing tuyeres, a coupling means between said system and the shell of the converter, at least one resonant chamber that envelopes the air blowing tuyere and at least one transducer placed inside said resonant chamber, for applying mechanical waves that contain a great number of components of different amplitudes that travel with the airflow into the converter or pyrometallurgical furnace.

Abstract: A submerged nozzle for continuous thin-slab casting by which a high quality thin-slab strand may be stably supplied for a long time in a continuous manner is provided, as a drift current and surface fluctuation of molten steel in the nozzle and a mold are prevented, and adhesion of ground metal to the nozzle, the damages of the nozzle and the like are suppressed even under long time use.

Abstract: The present invention relates to a clamping device including at least two assemblies each composed of a clamp (10) pivoting about a horizontal axis (11) and fitted with a groove (12) receiving a shoe (13) generally cylindrical in shape incorporating a flat surface (14) parallel to the axis of said cylinder, said shoe being capable of pivoting in the groove.

Abstract: Methods and apparatus for efficient utilization of a cryogen in inerting of solid and molten metals are presented. One method and apparatus of the invention includes providing a source of liquid cryogen; transporting the liquid cryogen through a conduit connected to the source of liquid cryogen to a gas/liquid separator, wherein a portion of the liquid cryogen transforms into gaseous cryogen en route; transporting a portion of the liquid cryogen through a first conduit connecting the gas/liquid separator to a cryogen supply nozzle; transporting the gaseous cryogen through a second conduit connecting the gas/liquid separator to a cryogen supply nozzle; and flowing at least a portion of liquid cryogen and at least a portion of the gaseous cryogen through the cryogen nozzle separately and near a surface of solid or molten metal. Thus liquid that transforms into gaseous cryogen en route from storage is not vented and not wasted, but used in inerting of solid or molten metals.

Abstract: A blast tuyere for shaft furnaces, includes a conical hollow main body having inner and outer casings defining a hollow space and interconnected by a tuyere nose. The outer casing is formed by a single-piece base body terminating smoothly in the tuyere nose, and the inner casing is formed by a conical weld-in part. The hollow space is divided in antechamber, adjacent the tuyere nose, and main chamber, completely separated hydraulically and including separate coolant circuits. The coolant circuit for the antechamber includes two parallel passages for supply and return of coolant. The passages terminate in a ring channel, arranged in the tuyere nose in a direction transversely to the passages, and are located in an area of an upper apex of the main body radially outside the main chamber. The coolant circuit for the main chamber includes a helical cooling passageway whose inner wall is formed by the weld-in part.

Abstract: Methods and apparatus for efficient utilization of a cryogen in inerting of solid and molten metals are presented. One method and apparatus of the invention includes providing a source of liquid cryogen; transporting the liquid cryogen through a conduit connected to the source of liquid cryogen to a gas/liquid separator, wherein a portion of the liquid cryogen transforms into gaseous cryogen en route; transporting a portion of the liquid cryogen through a first conduit connecting the gas/liquid separator to a cryogen supply nozzle; transporting the gaseous cryogen through a second conduit connecting the gas/liquid separator to a cryogen supply nozzle; and flowing at least a portion of liquid cryogen and at least a portion of the gaseous cryogen through the cryogen nozzle separately and near a surface of solid or molten metal. Thus liquid that transforms into gaseous cryogen en route from storage is not vented and not wasted, but used in inerting of solid or molten metals.

Abstract: An apparatus for producing a reduced metal includes a moving hearth reducing furnace, a feeding section, a metal discharge section, a gas discharge section, and a regenerative burner. The moving hearth reducing furnace heats a raw material composed of a metal oxide component and a carbonaceous reducing component to form the reduced metal. The feeding section feeds the raw material into the moving hearth reducing furnace. The metal discharge section discharges the reduced metal from the moving hearth reducing furnace. The gas discharge section discharges waste gas from the furnace and is disposed in a reducing process between the moving hearth reducing furnace and the metal discharge section. The regenerative burner functions as a heat source for the moving hearth reducing furnace.

Abstract: Nozzle for device to inject oxygen and technological gases used in metallurgical processing of metal melting, the nozzle being suitable to emit a gassy flow at supersonic velocity, the nozzle having a conformation symmetrical to a central axis (x) defined by a throat arranged between the inlet and the outlet, the throat defining an upstream part with a convergent development and a downstream part with a divergent development which ends in the outlet mouth, the nozzle with the convergent/divergent development having a geometry such that the fall in pressure of the gassy flow from inlet to outlet has a hyperbolic tangent development. Dimensioning method for the nozzle as above, the method providing an inverse dimensioning approach wherein the geometry of the nozzle is adapted to the natural profile of the fall in pressure of the gassy flow according to a hyperbolic tangent development, thus obtaining an optimum variation of the aerodynamic parameters according to the natural laws of expansion.

Abstract: A vertical shaft furnace for melting scrap metal, particularly copper scrap, uses one or more burners operated superstoichiometrically in order to provide excess oxygen to react with a waste gas stream passing up through the copper scrap thereby reducing the amount of carbon dioxide and visual contaminants in the waste gas stream.

Abstract: In a method for determining electromagnetic waves originating from the interior of a melt (3), in particular a metal melt, a gas-filled hollow space (26) is formed within the melt (3) by blowing in gas and electromagnetic waves emitting from the melt (3) are observed through the blown-in gas and evaluated by feeding the electromagnetic waves via an optical system (20) to a detector (22) for determining the temperature and/or chemical composition.

Abstract: A lance which may be used to establish a long coherent gas jet which includes a primary passageway having a converging/diverging nozzle, and two radially spaced secondary passageways for establishing a flame barrier, each of the passageways communicating with an injection space defined by a protective jacket.

Abstract: A method and an apparatus for producing metals and metal alloys from metal oxides in a metallurgical vessel containing a molten bath having a metal layer and a slag layer is disclosed. The method is characterized by injecting a carrier gas and a solid carbonaceous material and/or metal oxides into the molten bath from a side of the vessel that is in contact with the molten bath or from above the molten bath so that the solids penetrate the molten bath and cause molten metal to be projected into the gas space above the molten bath to form a transition zone. The method is also characterized by injecting an oxygen-containing gas into the gas space to post-combust reaction gases released from the molten bath into the transition zone.

Abstract: A desulfurization apparatus which employs first and second separate independently movable spaced apart lances (10, 12), each lance having a single conduit (22) through which the desulfurization materials may flow from feed vessels (40, 42, 44, 46) into the molten iron in a ladle (16). First and second independently operable raising and lowering apparatus (28, 30) are provided, the first raising and lowering apparatus (28) being connected to the first lance (10), and the second raising and lowering apparatus (30) being connected to the second lance. Each of the first and second raising and lowering apparatus (28,30) is capable of moving the associated lance (10, 12) from between a raised position where the lower end of the associated lance is spaced above the surface of the molten iron in the ladle and a lowered position where the lower end of the associated lance is spaced within the ladle at a proper location for desulfurization of the molten iron.

Abstract: A blast tuyere of a blast furnace making it possible that the temperature of Cu of the outer surface of the tuyere is not overheated to its melting point or higher so as to prevent tuyere failure and endure long-term use. This tuyere comprises a tuyere trunk 1 having a cooling chamber 2 of a tuyere body and a cooling chamber 3 of a tuyere nose. At least the upper half of the whole of the outer circumference surface of a portion being in the tuyere trunk and projecting into the blast furnace, or the whole excluding the forefront of the outer circumference surface is coated with a shell layer 5 made of a material having a higher melting point than the melting point of Cu and temperature of a hot metal in the blast furnace. Furthermore, a jacket 4 made of a metal for protecting the tuyere from mechanical impacts received at the time of inserting the tuyere into the blast furnace is fitted onto the outside of the shell layer.

Abstract: The present invention relates to an apparatus for supplying bottom-blown gas through a porous plug in a ladle and for molten metal refining. A gas supply pipe 3 is connected to a bottom-blowing porous plug 2 attached at the bottom of a ladle 1. An accumulator tank 11a, is provided in parallel with the gas supply pipe 3. The bottom-blown gas is accumulated in the accumulator tank 11a, and blown into the ladle 1 to agitate the molten metal through the gas supply pipe 3 during refining. After the refining is finished, the switching valve 4 of the gas supply pipe 3 is closed, the switching valve 4a of the accumulator tank 11a is opened and the bottom blowing of a small amount of gas is supplied, and the blowing apparatus 10 is separated from the gas supply source 6 at joint 5.

Abstract: A device for sealing a lance (12) in an opening in a container under pressure, in particular a shaft furnace, is described. The device comprises a first casing (46) with an end wall on the shaft furnace side and on the environment side, which are each provided axially with an opening for a lance (12), and a sealing element (14), which is arranged in the first casing (46). The sealing element (14) comprises at least one packing (50) and at least one axially movable annular piston (52), which are arranged coaxially with an axis (24) of the device, the packing (50) being arranged between the piston (52) and one of the end walls of the first casing (46) in the actuating direction of the piston (52). The packing (50) is pressed axially against one of the end walls of the casing (46) by actuation of the piston (52), the packing (50) extending radially and being laid around the lance (12) to form a seal.

Abstract: Method and apparatus for post-combustion (after-burning) of the combustible gases present in a metallurgical vessel used for smelting metals. A swirling flow of an oxidizing gas emanating from a radiant injector (10) having a funnel-shaped (conical) diffuser (14) causes a reaction between the combustible gases and the oxidizing gas at the inner surface (13) of the diffuser (14) thereby further heating the inner surface (13). Heat from the inner surface (13) of the diffuser (14) is radiated inside the vessel toward the metal (12). Fuel gas can be supplied to the radiant injector to aid in heating of the inner surface (13) of the diffuser (14).

Abstract: A gas blast nozzle for a furnace for processing molten metal has a prolonged service life and is free from gas leakage. The nozzle comprises a refractory block having a narrow straight bore and a small metal pipe slidably arranged in the straight bore. A gas is blown by the small metal pipe. When the gas blast nozzle is partially worn, the small metal pipe is moved upwardly to project into the furnace and the worn area is filled with a refractory material.

Abstract: A process and a device for introducing gases into a metal melt contained in metallurgical vessels via ducts arranged in the refractory lining of the vessel. In order to permit deeper penetration of the jet of gas and better mixing with the melt, an oscillating jet of gas is produced and introduced into the melt. For this purpose, several acoustic generators with which the gas is brought into contact with the melt are provided in the device.

Abstract: An annular nozzle for an oxygen lance, e.g. an oxygen lance for blowing steel in a converter, gives an annular hot spot on the liquid steel in the converter. When exiting the nozzle, the annular jet has disruptions that result in ambient atmosphere being sucked towards the center of the annular jet. Thus, a sub-pressure is prevented which would otherwise prevent the jet from diverging conically. In one embodiment, the nozzle can be switched during a blowing operation between forming a tight jet and forming a divergent jet.

Abstract: An improved oxygen blowing/fuel burner lance assembly for introducing, at selected times, a flow of oxygen and/or carbonaceous fuel material, such as fine-grained carbon or hydrocarbon gas (e.g., natural gas and the like), into an electric furnace vessel. The lance assembly includes a housing portion, a straight barrel having a first and connected to the housing portion and a second end connected to a lance tip. The lance tip includes a nozzle structure having at least one oxygen injection nozzle and at least one carbonaceous material injection nozzle which together define a burner assembly for dispensing a combined flow of carbonaceous fuel and oxygen from the lance which may be ignited to produce a flame for preheating a scrap charge in an electric furnace vessel.

Abstract: The present invention pertains to a gas purging means for wall-side installation in a metallurgical melting vessel.

Abstract: A method of and apparatus for treating molten metal to achieve effective removal of such unwanted inclusions as gases, alkali metals, entrained solids, and the like. The method comprises introducing molten metal into a trough, such as the trough provided between a melting furnace and a casting machine, providing at least one mechanically movable gas injector submerged within the metal in the trough and injecting a gas into the metal in a part of the trough forming a treatment zone through the injector(s) to form gas bubbles in the metal while moving the injector(s) mechanically to minimize bubble size and maximize distribution of the gas within the metal.

Abstract: A ladle port assembly having a longer use life than a conventional porous plug includes an inner refractory member constructed from a high-fired alumina-containing refractory material, a middle refractory member surrounding the inner member and also constructed from a high-fired alumina-containing refractory material, a plurality of channel openings at an interface between the inner and middle refractory members, an outer refractory member surrounding the middle member, and a steel housing which contains the three refractory members. The high-firing of the inner and middle members increases their durability and hardness, reduces wear during use, and reduces the clogging of the channel openings which, in conventional porous plugs, has been caused by erosion and other forms of wear.

Abstract: A blasting device to be used to introduce a gas and/or a solid material into a metallurgical vessel such as a convertor includes a plurality of blasting tubes arranged in a tube bundle, with ends of the tubes being inserted into respective receiving bores formed in a metal apertured plate, with a press fit therebetween. A space defined within the tube bundle is filled with a prefabricated ceramic internal member. The tube bundle with the internal member therein are positioned within a pressing mold that is partially filled with a portion of ceramic material to be used to form a blasting brick. The remainder of the ceramic material to form the blasting brick then is filled into the interior of the pressing mold. The mold then is operated to press the ceramic material to form a blasting brick with the tube bundle and internal member situated therein.

Abstract: A blasting device to be used to introduce a gas and/or a solid material into a metallurgical vessel such as a convertor includes a plurality of blasting tubes arranged in a tube bundle, with ends of the tubes being inserted into respective receiving bores formed in a metal apertured plate, with a press fit therebetween. A space defined within the tube bundle is filled with a prefabricated ceramic internal member. The tube bundle with the internal member therein are positioned within a pressing mold that is partially filled with a portion of ceramic material to be used to form a blasting brick. The remainder of the ceramic material to form the blasting brick then is filled into the interior of the pressing mold. The mold then is operated to press the ceramic material to form a blasting brick with the tube bundle and internal member situated therein.

Abstract: A device for coupling a metallurgical carriage to a flexible conduit comprises a first half-coupling mounted on the metallurgical carriage and a second half-coupling connected to one end of the flexible conduit. A coupling station is located near a predefined coupling position for the metallurgical carriage. This coupling station comprises a supporting block designed to receive and support the second half-coupling, driving means to move the supporting block from a parked position in the direction of the first half-coupling and vice versa. The second half-coupling is equipped with a locking device which can be actuated by a control device on the coupling station. In a first position of the locking device, the second half-coupling is coupled and locked to the first half-coupling; and in a second position of the locking device, the second half-coupling is coupled and locked to its support on the coupling station.

Abstract: The present invention pertains to a gas purging device for introducing gases and/or solid reactants into the metal melt of a metallurgical crucible, consisting of a gas purging plug, a well nozzle sleeve surrounding it, and/or a well nozzle surrounding the plug or the nozzle brick, with a mounting device arranged in the area of the respective end face.

Abstract: A porous plug assembly for use in a vessel containing molten metal, such as a melting furnace or a holding furnace, for introducing fluxing or other gases into the molten metal. The porous plug assembly includes a frustoconical porous refractory core member that is enclosed around its side and bottom by a non-porous refractory lining. Positioned about the outer surface of the non-porous refractory lining is a metallic outer liner, preferably made from inconel, which includes a ceramic anti-corrosion coating. A gas distribution pipe, which also can be made from inconel, extends upwardly through the bottom of the metallic outer liner, through the non-porous refractory lining, and into the interior of the core member for introducing a fluxing gas therein. Surrounding the intermediate, non-porous refractory lining and the metallic outer liner is a refractory nest block. The fluxing gas passes through the porous core member and exits at the top thereof to enter the molten metal melt.

Abstract: An oxygen/carbon blowing lance assembly for directing a supersonic flow of oxygen and a flow of graphite against the surface of molten bath in a steelmaking electric furnace. The two flows impinge upon the slag surface at discrete separate areas in the slag and the supersonic oxygen flow acts to emulsify the slag. The lance assembly includes a coolant shut off valve to prevent loss of coolant upon failure of the nozzle. The housing of the lance assembly includes a modular design for ease of maintenance.

Abstract: For the purposes of better cooling and improving the starting conditions of a direct current arc furnace, there is provided a hearth electrode which comprises at least one metal bar passing through the hearth wall and which is cooled by at least one cooling duct which extends along the metal bar to the inner end thereof and opens into the interior of the furnace.

Abstract: The invention relates to a method and an apparatus for sealing tuyeres and feed pipes installed in a refractory vessel lining. Seals known per se, in particular prestressable packings, are installed in the gap between the tuyere or feed pipe and the surrounding refractory material in order to avoid backflow of media.

Abstract: Molten metal in an electric arc furnace is stirred by introducing a gas into the melt through tuyeres mounted in the hearth. Each tuyere has an inlet portion having a passage of relatively large diameter and an outlet portion having a passage of relatively small diameter. The tuyere is mounted in the bottom of the electric arc furnace with the inlet portion extending through the furnace shell and part of the refractory brickwork. With this design of tuyere gas at conveniently available pressure (16 bar A) can be fed to the tuyere and leaves the outlet portion at least at sonic velocity thus forming a relatively stable jet which inhibits molten metal entering the tuyere. The outlet portion may have a first portion with a slightly larger internal diameter than a second portion downstream of the first portion. When the second portion is fully eroded the flow of gas increases and triggers an alarm.

Abstract: The present invention pertains to a gas purging plug for metallurgical vessels with a gas connection pipe at the gas inlet-side, lower end.

Abstract: A self-cooling lance or tuyere for the conveying of gases, liquids or solids into or onto a metallurgical bath comprises a heat pipe or thermosiphon made of two tubular members adapted to be immersed in a furnace environment at one end, such tubular members defining a closed annular chamber therebetween for containing a working substance adapted to evaporate in the region of the heat pipe which is in the furnace environment and flow toward the end which is out of the hot environment where it condenses and flows back to the evaporator region. Means are provided for introducing the gases, liquids or solids to be conveyed into the bath through the inner tubular member of the lance.

Abstract: A thermally stable refractory coating for iron-based piping and a method of forming the same is provided. The refractory coating comprises from about 30 to about 35 weight percent sodium silicate; from about 31 to about 36 weight percent course silica, about 80 to about 200 mesh; from about 12 to about 16 weight percent fine silica, about 325 to about 400 mesh; from about 1 to about 6 weight percent hydrated aluminum silicate clay; from about 1 to 4 weight percent graphite; from about 0.8 to about 0.9 weight percent sodium aluminate; and, from about 3 to about 5 weight percent magnetite M.S-200.The invention also concerns a method of forming the above-described coating on iron-based piping.