Abstract: Process for removing inorganically— and/or organically-bound carbon from a precious metal-containing composition inside an oven chamber comprising at least one direct burner and at least one exhaust gas conduit, characterised by the sequence of steps of: a) providing a precious metal-containing composition comprising fractions of inorganically— and/or organically-bound carbon inside the oven chamber; b) closing the oven chamber; c) heating the content of the oven chamber by means of at least one direct burner in order to establish a temperature T1 in the range of 450° C. to 1,000° C. and maintaining temperature T1 for 5 min-48 h; whereby, once the oven chamber is closed, any gas exchange between the oven chamber and the surroundings can take place only via the at least one direct burner and the at least one exhaust gas conduit.

Abstract: A method of providing an inerting atmosphere to the surface of molten aluminum in a vortex charge well of a reverberatory melting furnace is provided. The purpose is to improve aluminum recovery (reduce aluminum oxidation melt loss) by displacing the ambient atmosphere above the molten vortex with an inert gas. The method includes introducing a flow of an inerting gas into an inerting region immediately above the surface of the vortex charge well. The inerting gas may be selected from the group consisting of nitrogen, argon, or a mixture thereof. The inerting gas may be introduced into the charge inlet chute, through a diffuser, or a ring manifold. The vortex charge well may include a lid.

Abstract: Aspects of this molten aluminum refining system include a rotor based injection system which provides for the injection and dispersion of both gas and flux for refining molten aluminum.

Abstract: Ultrasonic probes containing a plurality of gas delivery channels are disclosed, as well as ultrasonic probes containing recessed areas near the tip of the probe. Ultrasonic devices containing these probes, and methods for molten metal degassing using these ultrasonic devices, also are disclosed.

Abstract: An aluminum alloy for producing an aluminum strip for lithographic print plate carriers, a method for producing an aluminum alloy for lithographic print plate carriers, in which, during the production of the aluminum alloy, after the electrolysis of the aluminum oxide, the liquid aluminum, up to the casting of the aluminum alloy, is supplied to a plurality of purification steps, as well as an aluminum strip for lithographic print plate carriers and a corresponding use of the aluminum strip for lithographic print plate carriers include a carbide content of less than 10 ppm, and preferably less than 1 ppm. As a result, the aluminum alloy, the method for producing the aluminum alloy, the aluminum strip, and corresponding use of the aluminum strip for lithographic print plate carriers described herein allow for the use of virtually gas-tight coatings.

Abstract: Provided are a method and an apparatus for melting an aluminum powder, which are capable of melting the aluminum powder with a high yield and allow the melted aluminum to be reused for a variety of applications. The method for melting the aluminum powder includes the steps of: preparing a mixture (M) including an aluminum powder (A) and a fluoride-based flux (F) by previously mixing the aluminum powder (A) and the fluoride-based flux (F); and melting the mixture (M) in molten aluminum (L).

Abstract: Methods for degassing and for removing impurities from molten metals are disclosed. These methods can include operating an ultrasonic device in a molten metal bath, and adding a purging gas into the molten metal bath through the tip of the ultrasonic device.

Abstract: A method and a device for admixture of powder in a liquid, whereby the method comprises that the liquid in a supply (14), influenced by underpressure in a crucible (12) to which the liquid is to be transferred, flows through a drain tube (6) out of the supply (14), the powder is dosed from a powder receptacle (1) and is driven by a gas, and the mixture of powder and gas is added to the liquid in the drain tube (6) and mixed therewith, whereupon the mixture flows into the crucible (12). The device comprises a supply (14) from which the liquid may flow and a receptacle (1) with powder, whereby a drain tube (6) connects the supply (14) with a receiving receptacle (12) which can be held at an inner underpressure. A device (4) for supply of a driving gas for the powder is connected to a mixing chamber (3) at an outlet from the powder receptacle (1), while the mixing chamber (3) is connected to the drain tube (6) for supply of powder to the liquid flowing in the drain tube.

Abstract: The present invention describes an apparatus and a process for in-line substantially continuous degassing of aluminium and/or aluminium alloys, in absence of chlorine and through the injection of at least one metal halide salt that includes a halogen and water and an inert gas, in a transfer trough before casting.

Abstract: Molten aluminum is heated in the range of 900° C. to 1300° C. under a nitrogen atmosphere using magnesium as an auxiliary agent to form aluminum nitride directly on the molten aluminum and bond the aluminum nitride to the aluminum so that an Al—AlN composite material is formed. Because aluminum nitride power needs not to be sintered at high temperature equal to or higher than 1900° C., the Al—AlN composite material can be formed at low temperature in the range of 900° C. to 1300° C. compared with the high temperature equal to or higher than 1900° C., and thereby the high-density aluminum nitride can be obtained.

Abstract: The present invention concerns a high vacuum in-situ refining method for high-purity and superhigh-purity materials and the apparatus thereof, characterized in heating the upper part and lower part of crucible separately using double-heating-wires diffusion furnace under vacuum, thereby forming the temperature profile which is high at upper part and low at lower part of crucible, or in reverse during different stages; then heating the crucible in two steps to remove impurities with high saturation vapor pressure and low saturation vapor pressure respectively in efficiency; and obtaining high-purity materials eventually. The whole procedure is isolated from atmosphere, reducing contamination upon stuff remarkably. The present invention could provide products with high-quality and high production capacity, which are stable in performance, therefore is reliable and free from contamination.

Abstract: A rotary device for treating molten metal, said device comprising a hollow shaft (30) at one end of which is a rotor (40), said rotor (40) having:—a roof (42) and a base (44), said roof (42) and base (44) being spaced apart and connected by a plurality of dividers (50); a passage (52) being defined between each adjacent pair of dividers (50) and the roof (42) and the base (44), each passage (52) having an inlet (54) in an inner surface of the rotor (40) and an outlet (56) in a peripheral surface of the rotor (40), each outlet (56) having a greater cross-sectional area than the respective inlet (54) and being disposed radially outward therefrom; a flow path being defined through the shaft (30) into the inlets (54) of the passages (52) and out of the outlets (56); and a chamber (48) in which mixing of the molten metal and gas can take place; wherein a plurality of first cut-outs (58a) are provided in the roof (42) and a plurality of second cut outs (58b) are provided in the base (44), each of the first and seco

Abstract: Aspects of this molten aluminum refining system include a rotor based injection system which provides for the injection and dispersion of both gas and flux for refining molten aluminum.

Abstract: The invention relates to a rotary device for dispersing a gas in a molten metal. The device comprises a hollow shaft at one end of which is attached a rotor. The rotor has a roof and a base which are spaced apart and connected by a plurality of vanes. A compartment is defined between each adjacent pair of vanes and the roof and the base, and each compartment has an inlet and first and second outlets. A flow path is defined through the shaft into the inlets of the compartments and out of the first and second outlets. Each first outlet is disposed radially outwardly of the respective inlet and arranged to disperse gas laterally of the rotor in use, and each second outlet is disposed in the roof of the rotor and arranged to disperse gas upwardly from the rotor in use.

Abstract: A system for producing a metal foam comprises a bath containing a molten metal, a rotating shaft or impeller extending through the base of the bath into, and submerged in the molten metal, and a gas discharge nozzle provided on the submerged end of the shaft. The opposite end of the shaft is connected to a gas supply line and the shaft is rotated with a motor. A seal is provided at the opening in the base of the bath for preventing leakage of the molten metal there-through.

Abstract: The present invention describes an apparatus and a process for in-line substantially continuous degassing of aluminium and/or aluminium alloys, in absence of chlorine and through the injection of at least one metal halide salt that includes a halogen and water and an inert gas, in a transfer trough before casting.

Abstract: A gas injection tube includes a first end adapted to connect to a reactive gas source and a second end. A tube base attaches to the second end of the gas injection tube. The gas injection tube includes a passageway and the tube base includes a channel. The passageway communicates with the channel to provide gas to a molten metal stream traveling through the channel.

Abstract: A heating system includes a furnace configured to receive a product to be thermally treated within the furnace, where the furnace includes at least one burner to generate combustion gases from a source of oxygen and a carbon-based fuel source provided to the burner, and the combustion gases provide heat to the product disposed within the furnace. A gas pipeline delivers a heated inert gas into the furnace at a location proximate the product so as to at least partially surround and protect a surface of the product and minimize or prevent the product from chemically reacting with other gases within the furnace.

Abstract: Disclosed are cover gas compositions comprising at least one pentafluoropropane for impeding the oxidation of molten nonferrous metals and alloys, such as magnesium.

Abstract: Disclosed are cover gas compositions comprising fluoroolefins for impeding the oxidation of molten nonferrous metals and alloys, such as magnesium.

Abstract: An inline degassing apparatus for removing solid solution gases as well as nonmetallic inclusions from molten metal in a degassing container, to which the molten metal is continuously introduced for degassing operation and from which the degassed molten metal is continuously removed. A rotary diffusing device is arranged in the degassing container for generating bubbles of inert gas diffused into the molten metal, thereby entrapping solid solution gases as well as nonmetallic inclusions into the bubbles, which are then floated and separated. Heaters are provided, which extend, in a cantilever fashion, from a side wall of container at a position adjacent the bottom wall of the container substantially parallel to the bottom wall.

Abstract: Cellular metal foam having closed cell walls is produced by introducing gas bubbles of suitable size and at a suitable rate below the surface of an otherwise non-stirred or non-agitated molten metal bath. For example, aluminum-silicon alloy, including silicon carbide foam stabilization particles has been thus processed into cellular metal of, as low as, one to two percent relative density and with good cell walls and quite regular cell size.

Abstract: A tool or fluxing head for fluxing molten metal that comprises a fluxing gas supply line that communicates with the interior of an inverted plunger cup providing a hollow interior into which refining agents and other additives that are to be introduced into a molten metal can be incorporated. In use, the fluxing head is introduced into a molten metal body with the plunger cup in the inverted position. The inverted plunger cup has a closed top at the point where the gas supply line enters and an open bottom that allows molten metal to enter the inverted cup to make contact with the refining agent or other additive. Apertures are provided in the wall of the inverted plunger cup to allow gas introduced therein to escape therefrom. According to a preferred embodiment, a porous layer is provided at the top of the inverted plunger cup to allow for the escape of gas into the molten metal through the porous layer.

Abstract: A method of heating molten aluminum in a container utilizing gas stirring means.

Abstract: A process for melting an aluminum charge into molten aluminum and simultaneously refining the molten aluminum to produce a refined molten aluminum having a low hydrogen content in a direct fired furnace (10) is provided.

Abstract: Equipment for the treatment of a liquid such as a metal melt has one or more rotors (5) for the supply of gas and/or particulate material to the liquid in a reaction chamber (1). The reaction chamber (1) is closed and has an inlet (3) and an outlet (13) and is designed to be placed under a vacuum. The outlet (13) communicates with another chamber or outlet passage (2). The equipment may have several reaction chambers (1, 2) arranged in series. The first reaction chamber (1) then communicates with the second reaction chamber (2), the second reaction chamber with a third, etc. via an opening (16).

Abstract: An apparatus for treating, in particular purifying or degassing, molten metal (40), comprising a component (10) exposable to molten metal to be treated and means (13) for imparting a rotary motion to the molten metal (40) about a substantially vertical axis. The apparatus is so arranged that during use at least part of a wear-exposed surface of the component (10) is temporarily or permanently in contact with molten metal (40), the contacting molten metal being in motion relative to the wear-exposed surface. The wear-exposed surface is coated with a slurry-applied protective coating (18A,18B) of refractory material in a heat stable binder, in particular an inorganic colloidal and/or polymeric binder, protecting the wear-exposed surface against erosion, oxidation and corrosion.

Abstract: Improved apparatus and method are described for the removal of light metals; sodium, lithium, calcium and magnesium, from virgin aluminum tapped from a Hall Heroult reduction cell using LiF-modified or LiF+MgF2 electrolyte. The method is performed in a crucible or at a station intermediate between the cells and furnaces in a cast house. Fine particulate aluminum fluoride and/or sodium aluminum tetrafluoride are transported by a gas or gas mixture into the molten aluminum in a manner such that the light metals are preferentially removed or their concentration substantially lowered through: a) the axle of a specially designed spinning impeller; b) partially through the axle of a specially designed spinning impeller and partially through one or more pipes equipped with dispersers for dispersing into the molten metal flow close to the spinning impeller; or c) through one or more pipes equipped with dispersers for dispersing into the molten metal flow close to the impeller fastened to a solid axle.

Abstract: A method of grain refining aluminum, the method comprising providing a molten aluminum body containing at least one of the metals selected from the group consisting of titanium, zirconium, vanadium, molybdenum, manganese, silicon, tungsten, tantalum, niobium and beryllium. A material reactive with the titanium is introduced preferably in gaseous form to the aluminum body. The material has a component selected from the group consisting of boron, carbon, sulfur, nitrogen and phosphorus. The material and said metal form a grain refining compound adapted for grain refining the aluminum.

Abstract: A shaft for use in a method for treating molten aluminum using an impeller mounted on the shaft comprising a protective refractory sleeve resistant to attack by molten aluminum, the protective sleeve mounted on the shaft by casting to extend above and below the molten aluminum surface when the shaft is in use.

Abstract: A method of heating a body of molten metal passing through a treatment bay. The method comprises providing a body of molten metal in a treatment bay and providing a baffle heater in the treatment bay to contact the molten metal. The baffle heater is comprised of a member fabricated from a material substantially inert to the molten metal, the member containing at least one heating element receptacle. An electric heating element is positioned in the receptacle for heating the member, the element protected from the molten metal by the material constituting the member.

Abstract: A method of grain refining aluminum, the method comprising providing a molten aluminum body containing 1 to 3000 ppm titanium. A material reactive with the titanium is introduced preferably in gaseous form to the aluminum body. The material has a component selected from the group consisting of boron, carbon, sulfur, nitrogen and phosphorus. The material and said titanium form a grain refining compound adapted for grain refining the aluminum.

Abstract: Offgas recycling processes, including an argon degassing embodiment which cyclically regenerates one treatment flow path while the other treatment flow path is treating the offgas. The system is changed into a second mode to regenerate the previously treating portion of the system while the offgas is being treated by the previously regenerated treatment device. A second embodiment oxidizes a copper chloride bed to release chlorine, which is injected into the melt. The offgas contains chlorine and HCl, which react with a second bed, containing oxides of copper, forming copper chloride. Water vapor and nitrogen are exhausted to the environment. Before the beds are fully reacted, the flow of gas through the beds is reversed, oxidizing the CuCl bed and reducing the copper oxides.

Abstract: An improved method for processing a body of molten metal using an impeller and a rotatable container, the method including increasing shear forces in the body of molten aluminum and reducing vortex formation, the method comprising the steps of providing a body of molten metal in a container and projecting an impeller on a shaft into the body. The impeller is rotated in one direction and the container and the body of molten metal is rotated counter or in a direction opposite of rotating the impeller, the container and the impeller being rotated at a rate which minimizes vortex formation and which maximizes shear forces in the body for purposes of improved processing.

Abstract: A system and device for removing impurities from molten metal comprising a pump within a chamber having an outlet port. The pump creates a flow or stream of molten metal through the outlet port. One or more gas-release tubes are provided adjacent the outlet port, each gas-release tube having one or more gas-release openings adjacent the outlet port. Gas is introduced into the gas-release tube(s) whereby it escapes through the openings into the molten metal stream thereby removing impurities from the molten metal. The system may further comprise a gas-release block, having one or more openings, mounted adjacent the bottom of the outlet port, partially within the molten metal flow. Gas is introduced into the block through a gas-transfer device where the gas escapes through the openings and enters the lower portion of the molten metal stream. Finally, the system may further comprise a metal-transfer device for containing the molten metal stream.

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 continuously introducing molten metal into a container forming a trough or trough section, such as the trough provided between a melting furnace and a casting machine, providing at least one mechanically movable gas dispenser submerged within the metal in the container and introducing a gas into the metal adjacent to the gas disperser in a part of the trough forming a treatment zone such that the gas is broken into smaller bubbles by the gas dispenser and dispersed through the treatment zone. The trough or trough section is such that it exhibits a static to dynamic metal holdup of less than 50%.

Abstract: An improved method for dispersing high levels of fluxing gas in a body of molten aluminum using an impeller or disperser to disperse the fluxing gas in the body of molten aluminum, the method producing increased shear forces in the body of molten aluminum and reducing vortex formation. The method comprises the steps of providing a body of molten aluminum and a disperser in the body. A fluxing gas is added to the body at the rate of 1 to greater than 200 SCF/hour and dispersed by rotating the disperser in one direction and thereafter reversing the direction of rotation to a counter direction. The direction of rotation is reversed periodically to substantially reduce formation of a vortex and to provide increased shear forces in the body for purposes of improving dispersion of the fluxing gas in the molten aluminum.

Abstract: An improved method for treating a body of molten aluminum using an impeller suitable for dispersing fluxing gas or solid particles in the body of molten aluminum. The method produces increased shear forces in the body of molten aluminum and reduces vortex formation. The method comprises providing a body of molten aluminum and projecting an impeller on a shaft into the body, the impeller comprising a rectangular-shaped body having a first rectangular-shaped face and a second rectangular-shaped face disposed substantially opposite the first face, the faces substantially parallel to the shaft and defined by a length L and a height H wherein the length L is greater than the height H.

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: There is provided an improved method for dispersing a treatment media in a body of molten metal using an impeller to disperse the media in the body of molten metal, the method producing increased shear forces in the body of molten metal and reducing vortex formation. The method comprises the steps of providing a body of molten metal and an impeller on a shaft in the body. A treatment media is added to the body and dispersed by rotating said impeller in one direction and thereafter reversing the direction of rotation of the impeller to a counter direction. The direction of rotation of the impeller is reversed periodically to substantially reduce formation of a vortex around the shaft of the impeller and to provide increased shear forces in the body for purposes of improving treatment of the molten metal by improved dispersion of the media therein.

Abstract: Disclosed is an improved method for dispersing a treatment media in a body of molten metal using an impeller, nozzles, and other mixing means to disperse the media in the body of molten metal, the method producing increased shear forces in the body of molten metal and preferably reducing vortex formation. In one embodiment, the method comprises the steps of providing a body of molten metal and an impeller on a shaft in the body. A treatment media is added to the body and dispersed by rotating said impeller in one direction and thereafter reversing the direction of rotation of the impeller to a counter direction. The direction of rotation of the impeller is reversed periodically to substantially reduce formation of a vortex around the shaft of the impeller and to provide increased shear forces in the body for purposes of improving treatment of the molten metal by improved dispersion of the media therein.

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 improved process for treating a body of molten metal is disclosed wherein a rotating impeller is used to disperse treatment media in the body. The process comprises the steps of providing a body of molten metal to be treated, the body having an upper region and a lower region, and providing an impeller on a shaft in said body. Treatment media is added to the body and the impeller is rotated to disperse the treatment media in the body. During the process of treating the body, the impeller is moved periodically between the lower portion and the upper portion of the molten metal body to reduce vorticity therein and to improve dispersion of the treatment media.

Abstract: There is provided an improved method for dispersing a treatment media in a body of molten metal using an impeller to disperse the media in the body of molten metal, the method producing increased shear forces in the body of molten metal and reducing vortex formation. The method comprises the steps of providing a body of molten metal and an impeller on a shaft in the body. A treatment media is added to the body and dispersed by rotating said impeller in one direction and thereafter reversing the direction of rotation of the impeller to a counter direction. The direction of rotation of the impeller is reversed periodically to substantially reduce formation of a vortex around the shaft of the impeller and to provide increased shear forces in the body for purposes of improving treatment of the molten metal by improved dispersion of the media therein.

Abstract: Process and apparatus for improving fluxing gas dispersion in treating molten aluminum by increasing the fluxing gas surface area. The process includes the use of a molten body of aluminum and a gas dispersing unit in the body of molten aluminum, the dispersing unit having at least two, upper and lower dispersers (rotors) mounted on a shaft extending into the molten aluminum. The dispersing unit is rotated, and simultaneously with the rotating, a fluxing gas is added to the molten aluminum adjacent the lower disperser. The fluxing gas is dispersed by the lower disperser to provide finely divided bubbles and then re-dispersed with the upper disperser to effectively increase the fluxing gas surface area in the molten body.

Abstract: A device is described for injecting gas into molten metal, e.g. molten aluminum, in a furnace chamber. It comprises: (a) a stirring apparatus having a reservoir chamber separate from the furnace chamber, a connector portion with an orifice connecting the interior of the furnace and the reservoir for the passage of the molten metal between them through the connector portion, vacuum/pressure generating means connected to the reservoir chamber interior for alternatively and successively producing therein a vacuum for drawing molten metal into its interior from the furnace chamber and a positive pressure for expelling the molten metal therefrom into the furnace chamber through the orifice in the form of a high velocity stirring jet, and (b) gas injector means adapted to inject gas into the high velocity stirring jet such that the gas is broken down into a large number of small bubbles which are circulated throughout the furnace chamber with the stirring jet.

Abstract: A method for the preparation of a mixture of at least one reactive element or an alloy thereof and a liquid metal melt, including introducing the reactive element or alloy thereof, in a liquid state and under pressure, within, i.e. below the surface of, the metal melt, is provided. An apparatus to facilitate the method above is also provided. The apparatus includes a crucible, an immersion pipe that passes into the crucible, an accommodating vessel for storing the reactive element or alloy thereof and a pressure unit.

Abstract: A method for the production of master alloys intended for grain refining of aluminum melts and being of the type which comprises of aluminum and 1-15 percent by weight titanium, where titanium is present in the form of intermetallic crystals of titanium aluminide in combination with additives of carbon and/or nitrogen. The method is characterized by adding carbon and/or nitrogen to the aluminum melt in an amount corresponding to at least 0.01 percent by weight in the resultant solidified material. The addition of the carbon and/or nitrogen is effected in elemental form or in the form of dissociable carbon and/or nitrogen containing compounds, making said addition before of during an established thermodynamic state of dissolution of existing crystals of titanium aluminide, and bringing the melt into a thermodynamic state where crystals of titanium aluminide present grow in size and thereafter causing the melt to solidify. Also a master alloy produced according to the above method is claimed.

Abstract: A process is described for removing all reinforcing particles contained in metal matrix composite scrap materials. This new technique involves providing a treatment vessel for holding a melt of an aluminum matrix composite to be recycled. Heating means are provided for heating the contents of the vessel to a temperature in the range of 700.degree.-750.degree. C. Mixing of the melt is carried out by means of a power driven vaned rotary impeller and this impeller is operated under different conditions for different stages of the process. In the first mixing stage, the impeller is operated under vortex-forming conditions and a fluxing salt is added to the melt while a gas is injected through a gas outlet beneath the surface of the melt and near the rotating impeller. This causes the salt to rapidly mix with the melt and the inlet gas, providing a uniform distribution through the melt of gas bubbles each surrounded by a layer of liquid salt.

Abstract: An improved apparatus and method of the inline degassing of the molten metal employing a fluxing gas.