Abstract: A tuyere stock for a blast furnace comprises three pipes arranged end-to-end. Between the first and second pipes and between the second and third pipes there are flexible bellows units and a pair of links on opposite sides of the second pipe are connected at their ends through spherical bearings to the first and third pipes so as to permit relative movement between the first and third pipes in two mutually normal directions which are also normal to the longitudinal axes of the links.

Abstract: This invention relates to a lance/burner apparatus and a method for melting and refining metals. Combustion produced from an oxy-fuel or fuel-air-oxygen flame is used to preheat and melt scrap. Oxygen is introduced through a lance pipe into the molten scrap to refine the metal.

Abstract: Apparatus for introducing stirring and refining agents into molten metal in a vessel using a lance having an elongated refractory body with a bore extending inwardly of a first or upper end of the refractory body and terminating inwardly of a second or delivery end thereof. A plurality of small tubes are positioned within the refractory body and communicate with the bore and the exterior of the refractory body whereby gas introduces into the bore flows through the small tubes to the delivery end and sides of the lance and bubbles upwardly shielding the lance from the rapid erosion that occurs when molten slag and steel attack the material of the lance due to the chemistry and temperature of the molten metal.

Abstract: A protective device for a submersible lance to be used in a vessel of molten material, such as steel, prevents undesirable deposition of the material at the juncture of lance and probe by having in the lance a channel for gas, and by having between the lance and the probe a gas-conducting disk which projects this gas circumferentially onto the lower surface of the lance.

Abstract: A consumable lance for injecting oxygen and other gases such as argon below the surface of a molten metal bath the lance comprising an upper manifold portion, a lower nozzle end portion, and a plurality of gas conveying conduits attached to a structural support assembly and encased within a protective refractory covering.

Abstract: Liquid argon or nitrogen is poured with a lance into a furnace during the production of molten metal.According to the invention, the lance comprises a double wall in which a hole is respectively located in order to vent the argon or nitrogen gas to reduce the rate of diphasic. The tip of the lance is equipped with a diffuser to improve the liquid discharge.

Abstract: A device for introducing gas into a mass of molten metal from a location in the side wall of a vessel for creating a stirring action therein has a refractory body having a plurality of passageways transversely thereof, the refractory body being positioned in the safety and working refractory lining of a ladle or the like so as to communicate with the interior thereof and molten metal therein. Tubular members positioned in or communicating with the passageways extend from the refractory body and upwardly to a chilling device which in turn communicates with a gas delivery tube through which a desirable supply of gas, such as argon, is delivered under pressure for introduction into the molten metal.

Abstract: A device for introducing stirring gas into a mass of molten metal in a container by way of an opening in the container and a pocket block having a plurality of metered passageways extending therethrough, the pocket block forming a portion of a refractory lining in said container, the plurality of passageways being defined by a plurality of metal tubes arranged in a spiral configuration in circumferentially spaced relation to one another in fixed position in the pocket block which is formed of a suitable refractory, preferably vitrified. The plurality of metal tubes communicate with the single tube which extends through the bottom of the container and communicates with a supply of gas, such as argon.

Abstract: An injection valve which is positioned on the underneath portion of a teeming vessel is disclosed. The valve itself includes a mounting plate, and a well block nozzle which is in open communication with the metal being teemed in the vessel. Beneath the sliding injection plate a sliding plate carrier is positioned which is engaged by spring loaded rocker arms in order to maintain a compressive relationship between the sliding plate carrier, the sliding injection gate, and the stationary plate. Optionally the injection valve is fed by a plurality of injectants supplied which are adjusted by means of a control valve. In addition, wire may also be injected simultaneously with gas, or other additives. In addition, power means are provided for replacing the sliding plate carrier, and also the sliding plate. Alternatively means are provided for disengaging the rockers, and manually replacing the same.

Abstract: For injecting substances into a liquid e.g. molten metal, a nozzle block is mounted in the wall of a vessel containing the liquid. Initially, an injection passage extending through the block is closed by a plug to prevent ingress of liquid, and only when injection is to commence is the plug thrust aside by a delivery pipe movable in the passage, the pipe forming part of an injection lance assembly. The positions of the lance assembly before and after injection are determined by a safety stop arrangement for example comprising a detent in the form of a spring-loaded plunger housed in a fixed part of the apparatus; the plunger coacts with front and rear ramps of an abutment which is fast with part of the lance assembly, to govern the positions of the lance assembly before and after injection.

Abstract: An injection valve which is positioned on the underneath portion of a teeming vessel is disclosed. It may be positioned under a ladle, or under a tundish. The valve itself includes a mounting plate, and a well block nozzle which is in open communication with the metal being teemed in the vessel. Beneath the well block nozzle is a stationary plate, therebeneath a sliding plate which may be imperforate, perforate, or have an opening containing a porous plug or ceramic sieve depending upon the type of injection. Beneath the sliding injection plate a sliding plate carrier is positioned which is engaged by spring loaded rocker arms in order to maintain a compressive relationship between the sliding plate carrier, the sliding injection plate, and the stationary plate. Centrally of the sliding plate carrier is a coupler which, in turn, is connected to a further coupler, an injection hose, and an injection supply for delivering additives to the vessel through the injection valve.

Abstract: A melting furnace and method for melting metal comprising the injection of inert gas into molten metal at a defined location as a concentrated plume to create localized surface agitation, and high quality refractory surrounding the gas injection means at the furnace bottom.

Abstract: A blow lance for treating molten metal comprising a concentric metal pipe structure enclosed within a ceramic covering with a space defined between the pipe structure and the covering. A layer of heat-resistant elastic fibrous material, excluding a binder, is positioned in the space. Ducting means forming coolant ducts are located between the concentric pipes.

Abstract: An injection nozzle (10) is installed in the wall (13) of a liquid containment vessel (14) and comprises an assembly of refractory component bodies (18, 19, 20): injection passages (22) for receiving longitudinally movable lances (11) are provided in the nozzle and before injection commences, the passages are closed by cup-shaped refractory shells (30) embedded in one of the component bodies (18) adjacent a discharge end of the nozzle. Each shell has its base (31) united through a frangible shell portion (34) with the sidewall (32) and when injection is to commence, an associated lance (11) is forcibly driven at the base (31) to detach it by fracture of the shell portion (34) and from an opening through which an injectant can exit into the liquid. A push-out bung (26) may be incorporated in the nozzle body (18) between the base of the shell (30) and the discharge end of the nozzle (10).

Abstract: The invention relates to an immersion lance for the introduction of treatment media such as gases, more particularly inert gases and/or carrier gases by which solids such as slag-forming substances, carbon or the like are transported, into a vessel filled with liquid metal, more particularly for the treatment of pig iron or steel. The immersion lance comprises an inner metal tube for the supply of the medium and a refractory monolithic ceramic jacketing, which is supported by means of a reinforcement bearing against the inner tube, one or more outlet apertures being provided which penetrate the jacketing. The reinforcement bearing enclosing the inner tube is formed by at least one spirally coiled ribbed band forming rib members with uniform spacings and being connected to the inner rib.

Abstract: Disclosed is a heat resistant composite comprising a refractory coating on a metal substrate. The refractory coating is provided by mixing a refractory mortar with water, impregnating a water absorbent web of fibrous material with the liquid mixture, placing at least one layer of the impregnated web on a surface of the substrate as a coating, and drying the coating to remove the water and cause the refractory mixture to chemically bond. The substrate may be a pipe protected by the coating for use in injecting a refining agent beneath the surface of a molten metal composition comprising a scrap metal such as copper or aluminum.

Abstract: A gas washing device for supplying gas through a metallurgical vessel to molten metal therein includes a gas permeable sink positioned to extend through a wall of the metallurgical vessel. The sink has an inner end to be exposed to the molten metal and subject to wear thereby and an outer end. A gas inlet supplies an operational flow of gas from a gas supply to the outer end of the sink. A device is operatively mounted with respect to the sink and is responsive to a temperature rise indicative of a predetermined extent of wear of the inner end of the sink by the molten metal, to reduce the flow of the gas to a reduced flow less than the operational flow upon the inner end of the sink being worn or eroded to the predetermined extent. A detector detects or measures the reduced flow of gas.

Abstract: A metallurgical lance for injecting a material into molten metal is provided. The lance has a outer conduit with first and second ends, and a material carrier inner conduit for carrying the material to be injected into the molten metal. The inner conduit has a supply end and an injection end and is in part disposed within and throughout the outer conduit. A high temperature heat insulator is disposed around the outer conduit and extends along the outer conduit from at least an intermediate portion thereof to at least the first end thereof whereby all portions of the lance to be disposed in the molten metal are protected by the insulator. A first end closure and a second end closure for the outer conduit have centrally located apertures therein for receiving a portion of the inner conduit.

Abstract: The burner block or tile in industrial furnaces is conventionally made of refractory ceramic material. Such refractories are susceptible to cracking from thermal shock if the temperature of the burner block fluctuates during use. The life of the burner block can be greatly improved by making it in two parts: a cavity bounding inner part made from a material more shock resistant than a conventional refractory and a conventional refractory outer part. Best results are obtained with a thin inner liner of recrystallized silicon carbide having a thermal conductivity of over 18 W/(m K) and a modulus of rupture of at least 120 MPa.

Abstract: A device for bubbling gases through molten metal and specially adapted to be used in ladles or metallurgical vessels where it is necessary to stop the flow of gas without risk of penetration of liquid metal through the device. The device includes a metal casing holding a number of refractory plates or concentric cylinders that have opposed, specially roughened surfaces and that have their roughened surfaces juxtaposed without inserts or slots between them. The plates or cylinders can be roughened by controlled shot blasting to provide a plurality of randomly arranged surface discontinuities that define a plurality of unoriented flow passages when the plates or cylinders are placed in contacting, face-to-face relationship. Gas flow rates substantially greater than 5 liters per second can be obtained, and the device prevents molten metal flow therethrough when the gas flow has been cut off.

Abstract: A tuyere assembly and positioning method comprising mechanically separate or separable inner and outer tubes, the inner tube(s) being removeable and replaceable and the outer tube being extendable into a vessel and held in place by a flared end abutting the wall of a cavity through the vessel wall.

Abstract: An injection lance is provided for introducing flux mixtures and the like into baths of molten metal, which lance has inner and outer spaced metal tubes with between them a tubular sheath of refractory material that is spaced from both the inner and outer tubes by air gaps. The outer tube may be of high temperature metal with a refractory coating. The tubes can be maintained in coaxial relationship by an end cap at the inlet end of the lance and by rammed ceramic fibre insulation introduced at both ends, the outer tube at the discharge end being chamfered and containing a body of rammed insulation in which the inner tube is buried, with the terminal portion of the flow passage through the lance at the discharge end being provided as a passage formed through the rammed insulation.

Abstract: A vertical conduit extends from the bottom of a ladle containing molten metal and terminates at a lower end above a tundish for receiving the molten metal. A vertical shroud encloses the vertical conduit from a location above the conduits's lower end, and the shroud extends into the tundish. A nozzle extends into the interior of the shroud for feeding alloying ingredient, as shot, into a stream of the molten metal, within the shroud. Structure is provided for circulating a cooling fluid through the nozzle. The nozzle is connected to flexible feed lines for transporting shot and cooling fluid to the nozzle. Additional structure is provided for preventing the flexible feed lines from bending, twisting, kinking or the like when the nozzle, shroud and vertical conduit are rotated about a vertical axis spaced from the center line of the vertical conduit.

Abstract: A cartridge-type injection device (20) is removably seated in a passage (18) through the wall of a ladle (10) and comprises a refractory nozzle tip (21) fitted to one end of a tubular body (30), and a delivery pipe (35) for gas or a mixture of gas and a particulate material, the pipe (35) entering an outer end of the body (30) and extending therethrough into the nozzle tip (21). An insulating packing is contained by the body around the pipe (35). The pipe is movable in the bore (22) of the tip (21) for dislodging a melt-obstructing plug in the bore (22) into the melt, whereupon the device is enabled to eject the gas or mixture from the pipe into the melt.

Abstract: A plug comprises a refractory body having a plurality of gas passgeways through which gas is blown into a refining apparatus. Each gas passageway may be defined by at least two metal tubes which are longitudinally spaced apart from each other. Alternatively, each gas passageway may be at least partly defined by an electrically insulating tube. The plug may alternatively have a plurality of gas passageways each having a bare refractory wall, while the body is reinforced with nonconductive mineral fibers, or metal wires which do not continuously extend throughout the plug. The plug may further be provided with a plurality of elongated holes extending in parallel to the gas passgeways from the inner surface of the body facing the interior of the refining apparatus to an intermediate portion thereof.

Abstract: An oxygen lance for steelmaking is provided with a top adapter assembly of generally T-shaped configuration including a central tubular barrel and a transverse top plate which both contain the O'rings required to assure complete adequate sealing between the oxygen gas and the cooling medium utilized in the furnace.The O'rings are placed on the outside circumference of the central barrel and are held in place in grooves therein so that they cannot be accidentally displaced during oxygen blowing or during assembly and disassembly of the lance. Access to the O'rings is simplified and assured while maintaining complete sealing integrity of the T-shaped top plate and complete sealing reliability during operation. The T-shaped top plate carries the sealing O'rings in grooves provided in the tubular vertical barrel and in a transverse plate thus providing means whereby interchange of the bottom assembly in the lance combination is quickly achieved in the field or factory.

Abstract: Disclosed is a heat resistant composite comprising a refractory coating on a metal substrate. The refractory coating is provided by mixing a refractory mortar with water, impregnating a water absorbent web of fibrous material with the liquid mixture, placing at least one layer of the impregnated web on a surface of the substrate as a coating, and drying the coating to remove the water and cause the refractory mixture to chemically bond. The substrate may be a pipe protected by the coating for use in injecting a refining agent beneath the surface of a molten metal composition comprising a scrap metal such as copper or aluminum.

Abstract: A device for introducing gas into a mass of molten metal in a container, by way of an opening in the container and a pocket block having a passageway extending vertically therethrough, the pocket block forming a portion of a refractory lining in said container, a refractory plug and an open ended shell thereabout in spaced relation positioned in said passageway in said pocket block to form a gas passageway with said shell and refractory plug extending outwardly of and above said pocket block in protecting relation to said refractory plug with respect to molten metal introduced into said container and so as to form a hot metal dam protecting said gas passageway around said refractory plug. A ceramic plate larger than the refractory plug and pocket block is attached to the plug and pocket block to stop molten metal leaks.

Abstract: The invention relates to a sleeve for blowing solid materials into molten metal baths, specifically molten steel baths, through the wall of a ladle containing the molten metal bath. To improve the characteristics of such a sleeve, the invention proposes that a forward sleeve section, facing the molten metal bath, be made of an insulating material with lower thermal conductivity than that of the material of the middle and rear sleeve section.

Abstract: A gas washing device includes a permeable gas sink, a gas inlet for supplying gas through the sink to a molten metal container, a gas flow meter positioned upstream of the gas inlet, and a further gas sink having a gas permeability greater than that of the first-mentioned gas sink and positioned between the gas inlet and the first-mentioned gas sink.

Abstract: A casing assembly includes a nozzle brick to form part of a wall of a metallurgical vessel. The nozzle brick has therethrough a conical opening defined by a conical inner surface. A casing to be inserted into the conical opening has a truncated conical shape including a conical outer surface and an axially extending flow through opening. The conical opening and the casing have coaxial center axes, and the conical inner and outer surfaces extend at equal angles of inclination to such axes. The conical inner surface is jacketed with a thin metal shell having a conical shape with the same inclination as that of the conical inner and outer surfaces.

Abstract: Methods and apparatus are provided for reducing corrosion in a refractory lining of a liquid-containing vessel used in direct steelmaking processes. The vessel operates at between about 1600.degree. C. and about 1800.degree. C. and an oxygen partial pressure of about 10.sup.-12 atmospheres, creating slag which is rich in FeO. The refractory lining includes a significant level of chromium oxide (Cr.sub.2 O.sub.3), and has small interconnected pores which may be filled with a gas mixture having a higher total pressure and oxygen partial pressure than the total pressure and oxygen partial pressure associted with the liquid against the lining of the vessel.The gas mixture is forced through the pores of the lining so that the pores are continuously filled with the mixture.

Abstract: A water-cooled lance for blowing oxygen or oxygen containing gas onto a metal melt, for example an iron melt, for afterburning reaction gases from the melt and transfering the heat of afterburning back to the melt comprises a center tube forming a gas supply duct surrounded by further tubes for cooling water. The center tube leads to a head having a plurality of oxygen-blowing nozzles. Each of the nozzles has a plurality of oxygen outlet openings. The outlet openings have their centers lying on two concentric circles and are arranged so that each opening produces an individual gas stream. The axes of the outlet openings are inclined to the longitudinal axis of the lance at angles such that, in a plane perpendicular to the longitudinal axis of the lance and at a distance Lh from the head, the gas streams extend over an annular area in the plane having an inside diameter Di and and outside diameter Da. Lh, Di and Da have the following relationships:Di:Lh is the range of from 0.15 to 0.

Abstract: A solid non-permeable refractory plug of an inverted frusto-conical shape has a spaced metal jacket and is located in an inverted frusto-conical shaped cavity in a pocket block incorporated in the normal refractory lining of a ladle to provide a structure through which gas can be introduced into the molten metal in an unusually large annular stream. A tubular body member is attached to the smaller lower end of the refractory plug and metal jacket and extends downwardly through the refractory lining of the ladle and an opening in the bottom of the ladle to which it is secured by a fastener and through which gas is introduced into the ladle. The large annular stream of gas formed by the device results in an improved stirring action in the molten metal and displaces molten metal that would otherwise tend to flow into the device and close the gas passageway. The device is inserted into the pocket block by moving it downwardly through the ladle and the pocket block.

Abstract: A longitudinally expansible and contractible duct characterized by the employment of a pair of expansible and contractible bellows protected by internal, thermally insulated, baffles which are slidably secured to the external shell members of the duct to accommodate differential thermal expansion both longitudinally and radially of the duct.

Abstract: A device for injecting gas into a hot melt, particularly molten metal, is suitable for being installed in the wall, particularly the bottom wall, of the container holding the melt. The device has three main sections includinga front section of refractory material which is resistant to the melt in question, and which has a number of perforations (10) for introduction of gas into the melt,a middle section which at least partly consists of heat conductive material and possesses a number of perforations communicating with the perforations of the front section, anda rear section at least the outer (peripheral) part of which is of heat conducting material, which rear section in or close to its peripheral part has a helical duct communicating with the perforations of the middle section and adapted to pass the gas from an external gas source.

Abstract: A blast pipe (2) primarily intended for introducing gas, such as oxygen gas, into molten metal in metallurgical processes, such as steel manufacturing processes, including a pipe element (1) made preferably of steel and coated at least externally with at least one protective layer (3). The blast pipe (2) is particularly characterized by the fact that the pipe element (1) is provided with an external, preferably high compact layer (3,4) which mainly comprises organic fibres, preferably wood fibres in the form of paper, and by the fact that the fibre layer (3,4) is preferably completely or partially impregnated with a refractory substance.

Abstract: A method of oxygen lancing for a copper-producing converter. An oxygen-enriched gas, such as oxygen-enriched air or pure oxygen, having a gage pressure of at least 1 kg/cm.sup.2 is blown onto the surface of a molten bath through at least one top lancing tube of the non-immersion type having a lower end located within the converter and held at a height within 0.4 m above the surface of the bath as measured when the bath is at a standstill, while air is simultaneously blown into the bath through tuyeres.

Abstract: In an in-line refining vessel (50) having submerged porous plugs (20) for bubbling oxygen through the molten metal, a shroud device (52) to circulate nitrogen around the porous plug (20) and oxygen supply pipe (25).

Abstract: The invention relates to apparatus including a gas purge brick for metallurgical furnaces and vessels, which is connected with a gas supply pipe on its cold end remote from the interior of the furnace or vessel. Within the gas supply pipe there is centrally arranged a solid metal core which is surrounded by a helix. Optionally, at least the part of the gas supply pipe adjoining the cold brick end is surrounded by a protecting tube filled with a refractory material.

Abstract: The invention relates to a method and an apparatus for heating up a first gas-flow with a second gas-flow. The first gas-flow is caused to flow along a wall in a cylindrical chamber as a rotating gas-flow and the second gas-flow is caused to flow centrally in the chamber, surrounded by the first gas-flow, so that the wall is protected.The apparatus comprises a chamber having an inlet section designed as a whirlpool chamber and an elongate cylindrical mixing part non-radial inlets for the first gas-flow, having their orifices in the wall of the whirlpool chamber and having an inlet for the second gas-flow, arranged substantially centrally in the end of the whirlpool chamber facing away from the mixing part, as well as an outlet section arranged in the mixing chamber part opposite the whirlpool chamber.

Abstract: A gas-permeable element of a refractory material for blowing gases into a metal treatment vessel through its lining has a body of a refractory material, a metal housing on the longitudinal sides of the refractory body, a free inner end surface at which the refractory material is exposed, an outer end surface provided with a gas distributing chamber for a gas supply, at least one local opening extending in the interior of the refractory body for a gas passage between the end surfaces and provided with a metal insert, wherein the metal insert is formed as a laterally closed small channel, the gas-distributing chamber is separated from the refractory material by a metal sheet plate, and the metal channel is tightly mounted in the metal sheet plate so that the refractory material is maintained free from loading with a gas pressure.

Abstract: A liquid-cooled lance for blowing oxygen onto a bath of molten steel, has a tip (1) with at least one outlet from which a primary supply of oxygen is blown onto the bath, a central duct (2) for the supply of the primary oxygen surrounded by a double tube system (3,4) for supply and removal of cooling fluid, a plurality of secondary outlets (15) disposed around the lance in a conical widening of the lance axially spaced from the tip for blowing a secondary supply of oxygen and a plurality of secondary ducts (8, 9) extending along the lance for supply of the secondary oxygen to the secondary outlets. To obtain a high maximum possible scrap addition, and good control of final oxygen blowing temperature, there are at least eight of the secondary outlets (15) each having a diameter d.sub.s which satisfies the condition d.sub.s /1<0.02 where 1 is the axial distance between the outlets for respectively the primary and secondary oxygen.

Abstract: A solid non-permeable refractory plug has a spaced stainless steel and/or ceramic jacket and is located in a pocket block for incorporation in the normal refractory brick lining of a ladle to provide a passageway through which gas can be introduced into the molten metal. The stainless steel and/or ceramic jacket extends above the refractor plug and the pocket block to form a hot metal dam that protects the passageway from metal and/or slag penetration during the filling of the ladle with molten metal.

Abstract: A nozzle (4,5) for an injection lance, which is intended for injecting primarily powderous material into a metal bath, such as a steel bath, freely in a bath or in a casting nozzle, and which comprises preferably an outer, preferably ceramic pipe (1) and an inner, preferably metallic pipe (2), in which said material is intended, usually pneumatically, to be transported all the way to the tip (3) of the lance, at which tip the powderous material is intended to pass out through at least one nozzle (4,5) comprising a through passageway (6) for said material.The nozzle according to the invention is especially characterized in that the nozzle (4,5) is made of a material with high wear resistance and with a fusion point, which is higher than the fusion point of the material, into which the injection is to be made, for example steel.

Abstract: A safety arrangement in a so-called gas-cutting lance (1) arranged to be connected at one end (2) thereof, the attachment end, to a gas-supply handle (3) or like means for causing gas, primarily oxygen gas, to flow through the lance. The lance comprises a hollow tube (5) which preferably houses a core (6) of, for example, closely packed filaments (7). The tube and the core comprise a material having a high iron content and are intended to melt progressively at the free end of the lance and to burn, to oxidize, at least in part.The arrangement is characterized in that preferably at least the lance (1) includes at least one substantially tubular sleeve (8,9) or like member in the vicinity of the attachment end (2) of the lance.

Abstract: A novel tuyere assembly for a metallurgical furnace is disclosed having a tuyere pipe formed of extremely high thermal conductivity and heat diffusivity materials, wherein a heat sink and a water cooled chamber, positioned exteriorly of the metallurgical furnace, extract heat from the tuyere tip through efficient heat conductivity along the tuyere pipe, so as to overcome problems of knurdle size control and tuyere pipe burn-back.

Abstract: A replaceable liner assembly for a blast furnace tuyere comprises a tubular, metallic liner which fits within the tuyere and a plurality of layers of refractory fiber paper sandwiched between the tubular liner and the inside surface of the tuyere. There are gas-tight seals between the liner and the tuyere at opposite ends thereof to prevent gas from entering the space occupied by the refractory fiber paper. The liner is composed of a metal which has a good resistance to oxidation and a lower thermal conductance and higher melting point than the metal of which the tuyere is composed.

Abstract: An air cooled refractory lance useful for either inert gas stirring or injection of oxygen into molten metal has an elongated refractory body having an axial bore terminating inwardly of one end in which several metal conduits are positioned with one of the conduits extending outwardly of the refractory body and forming a support and a conduit for air being introduced into the lance for cooling. Another of the conduits extends completely through the refractory body in coaxial relation and provides a path for a gas stream directed therethrough.

Abstract: The object is to introduce a bottom-blown gas into a molten metal refining furnace so as to minimize the rate of blowing gas flow and increase the control range of the rate of blowing gas flow. There are included a refractory (1) having a plurality of holes (2) having an inner diameter of from 0.5 to 3.0 mm.phi. formed through said refractory and extending its working surface to its back, a metal cover (3) enclosing at least a part of the sides of the refractory (1) and a pressure box (4) formed in the bottom of the refractory (1) so as to communicate with the holes (2) and define a gas reservoir space. The molten metal is prevented from entering the holes (2) when the blowing gas pressure and the rate of blowing gas flow are decreased.