Abstract: The present invention discloses a device for plasma arc melting through magnetostatic soft-contact stirring and compounding, which includes a furnace body, where a water-cooled copper crucible and a tungsten electrode are mounted in the furnace body, the tungsten electrode is located above the water-cooled copper crucible, and a groove for containing a metal raw material is opened in the water-cooled copper crucible; and a drive shaft penetrates through a side wall of the water-cooled copper crucible, one end, located at the exterior of the water-cooled copper crucible, of the drive shaft is connected with a stepper motor, one end, located in the water-cooled copper crucible, of the drive shaft is sleeved with two rotary tables, magnets having reverse magnetisms are interleaved in the rotary table, and the rotary tables are located on two sides of the groove.

Abstract: A process for treating a zirconium containing feedstock includes fluorinating a feedstock comprising dissociated zircon (‘DZ’) to obtain a zirconium fluorine compound and a silicon fluorine compound. The zirconium fluorine compound is separated from the silicon fluorine compound is provided. Optionally, the zirconium fluorine compound is reacted with a non-fluorine halogen, an alkali metal non-fluorine halide or an alkaline-earth metal non-fluorine halide, thereby to obtain a zirconium non-fluorine halide. The zirconium fluorine compound or, when present, the zirconium non-fluorine halide is subjected to plasma reduction, in a plasma reduction stage, in the presence of a reductant, to obtain metallic zirconium.

Abstract: A plasma system for treating a workpiece is disclosed. The plasma system includes: a plasma device including an electrode formed from a metal alloy and a dielectric layer covering the electrode, the dielectric layer including a distal portion extending distally past a distal end of the electrode by a predetermined distance; a liquid source configured to supply a liquid to a workpiece; an ionizable media source coupled to the plasma device and configured to supply ionizable media thereto; and a power source coupled to the electrode and configured to ignite the ionizable media at the plasma device to form a plasma effluent in the presence of the liquid, whereby the plasma effluent reacts with the liquid to form at least one reactive species that interacts with the workpiece.

Abstract: The present invention describes an inoculation process for inoculating a nucleating additive to a cast iron alloy in a pouring distributor by means of using a transferred arc plasma torch, with an anode partially immersed in the cast iron alloy and a cathode located on the surface of said alloy, the anode or the cathode or both comprising graphite, preferably synthetic crystalline graphite, which supplies said nucleating additive to the iron alloy. The invention thus describes an inoculation device useful for carrying out the inoculation process.

Abstract: A melting furnace includes a waste inlet formed on a first side wall of the plasma melting furnace to feed waste therein, an exhaust gas outlet formed on a second side wall facing the first side wall and located diagonally to a direction orthogonal to the first side wall having the waste inlet to discharge the exhaust gas generated in the plasma melting furnace, and a plasma torch mounted on a third side wall for heating inside of the plasma melting furnace at a position nearer to the second side wall than the first side wall so as to inject a plasma into the exhaust gas.

Abstract: A method and an apparatus for treating return ores using plasma, capable of treating sintered return ores generated in a sintering process in a steel maker or return ores (iron ores) employed in other ironmaking process such as FINEX. The method of treating return ores using plasma includes: providing return ores sorted out by a sorting process; and bonding the return ores by fusing and agglomerating the return ores using plasma. Also, an apparatus for treating return ores using plasma includes a plasma heating device used to fuse and agglomerate sorted return ores. The return ores of a predetermined grain size are fusion-bonded and agglomerated using a flame of a plasma heating device. Particularly, the return ores can be treated in a massive amount to enhance productivity of a fusion-bonding process of the return ores. Furthermore, a great amount of sintered return ores generated in the sintering process can be subjected to a fewer number of re-treatment processes.

Abstract: Combustion flame-plasma hybrid reactor systems, chemical reactant sources, and related methods are disclosed. In one embodiment, a combustion flame-plasma hybrid reactor system comprising a reaction chamber, a combustion torch positioned to direct a flame into the reaction chamber, and one or more reactant feed assemblies configured to electrically energize at least one electrically conductive solid reactant structure to form a plasma and feed each electrically conductive solid reactant structure into the plasma to form at least one product is disclosed. In an additional embodiment, a chemical reactant source for a combustion flame-plasma hybrid reactor comprising an elongated electrically conductive reactant structure consisting essentially of at least one chemical reactant is disclosed. In further embodiments, methods of forming a chemical reactant source and methods of chemically converting at least one reactant into at least one product are disclosed.

Abstract: An apparatus for melting an electrically conductive metallic material includes a vacuum chamber and a hearth disposed in the vacuum chamber. At least one wire-discharge ion plasma electron emitter is disposed in or adjacent the vacuum chamber and is positioned to direct a wide-area field of electrons into the vacuum chamber, wherein the wide-area electron field has sufficient energy to heat the electrically conductive metallic material to its melting temperature. The apparatus may further include at least one of a mold and an atomizing apparatus which is in communication with the vacuum chamber and is positioned to receive molten material from the hearth.

Abstract: The invention relates to a process for the separation and recovery of non-ferrous metals from zinc-bearing residues, in particular from residues produced by the zinc manufacturing industry. The process comprises the steps of:—subjecting the residue to a flash or agitated bath fuming step, thereby producing an Fe bearing slag and Zn- and Pb-bearing fumes; and—extracting the Zn- and Pb-bearing fumes and valorizing Zn and Pb; characterized in that CaO, SiO2 and MgO are added as a flux before or during the fuming step so as to obtain a final slag composition with: formula (I) all concentrations being expressed in wt %. The invention also relates to a single-chamber reactor for Zn-fuming equipped with one or more submerged plasma torches as heat and gas sources. [ Fe ] [ SiO 2 ] + [ CaO ] [ SiO 2 ] + [ Mg ? O ] 3 > 3.5 ; ? ? 0.1 < [ CaO ] [ SiO 2 ] < 1.

Abstract: A melting furnace for smelting scrap includes a heating device extending through a wall of the furnace in order to supply melting energy, wherein the heating device including a tubular body, which encloses a flow channel. Further, the furnace includes a heating zone formed by a longitudinal section of the tubular body configured as an electrodeless plasma torch including an inductive heating coil which encloses the flow channel coaxially. An injection pipe is disposed in a central manner in the flow channel extending up or into to the heating zone, wherein the injection pipe is enclosed by a gas guiding pipe coaxially and at a radial distance. An annular channel is arranged between the injection pipe and the wall of the flow channel for supplying a cooling gas.

Abstract: A ceramic electrode for a gliding electric arc system. The ceramic electrode includes a ceramic fin defining a spine, a heel, and a tip. A discharge edge of the ceramic fin defines a diverging profile approximately from the heel of the ceramic fin to the tip of the ceramic fin. A mounting surface coupled to the ceramic fin facilitates mounting the ceramic fin within the gliding electric arc system. One or more ceramic electrodes may be used in the gliding electric arc system or other systems which at least partially oxidize a combustible material.

Abstract: The Inventive System disclosed herein relates to an improved system for extracting metals from ore.

Abstract: A process for recycling composite materials includes the steps of feeding a quantity of composite material composed of at least one polymer and aluminum into at least one first reactor; heating the composite material in a non-oxidizing environment at a temperature sufficient to volatilize the at least one polymer and form a hydrocarbon by-product and aluminum in the at least one first reactor; feeding the aluminum free of the at least one polymer into a second reactor; and heating the aluminum in a non-oxidizing environment at a temperature sufficient to melt the aluminum in the second reactor.

Abstract: A transferred plasma heating anode for heating a molten metal in a container by applying Ar plasma generated by passing a direct current through the molten metal, the transferred plasma heating anode comprising; an anode, composed of a conductive metal, that has an internal cooling structure, a metal protector having an internal cooling structure that is placed outside the anode with a constant gap between the anode and the protector, and a gas supply means that supplies an Ar-containing gas to the gap, is characterized by the central portion on the external surface of the anode tip end being inwardly recessed.

Abstract: The object of this invention is to provide an ash-melting furnace which can respond to fluctuations in the load and which will be capable of highly efficient and stable operation. In an ash-melting furnace which heats and melts the primary ash and the fly ash obtained by combustion together, this invention is characterized by supplying the primary ash (ash containing rough particles) from upper end of the furnace to form an upper layer of a two-tiered layer of ash, supplying the fly ash (ash containing minute particles) from an upper end of the furnace to form a lower layer of the two-tiered layer of ash, moving the two-tiered layer together towards the far end of the furnace, and heating and melting the two-tiered layer by a burner to form molten slugs during the moving step. When the burner is an oxygen-enriched burner, this configuration makes it possible to control the volume of oxygen to be added to the burner air (including changing the density of the oxygen).

Abstract: The present invention provides tunable waste conversion systems and apparatus which have the advantage of highly robust operation and which provide complete or substantially complete conversion of a wide range of waste streams into useful gas and a stable, nonleachable solid product at a single location with greatly reduced air pollution to meet air quality standards. The systems provide the capability for highly efficient conversion of waste into high quality combustible gas and for high efficiency conversion of the gas into electricity by utilizing a high efficiency gas turbine or an internal combustion engine. The solid product can be suitable for various commercial applications. Alternatively, the solid product stream, which is a safe, stable material, may be disposed of without special considerations as hazardous material.

Abstract: The present invention provides a relatively compact self-powered, tunable waste conversion system and apparatus which has the advantage of highly robust operation which provides complete or substantially complete conversion of a wide range of waste streams into useful gas and a stable, nonleachable solid product at a single location with greatly reduced air pollution to meet air quality standards. The system provides the capability for highly efficient conversion of waste into high quality combustible gas and for high efficiency conversion of the gas into electricity by utilizing a high efficiency gas turbine or by an internal combustion engine. The solid product can be suitable for various commercial applications. Alternatively, the solid product stream, which is a safe, stable material, may be disposed of without special considerations as hazardous material.

Abstract: A method for providing main gas into a pool of molten metal, which is particularly useful for use in an electric arc furnace. The method employs combustion of secondary oxygen with fuel to form a flame envelope around a main gas stream which protects the main gas from entrainment of ambient gases as it passes through the headspace of the furnace. This enables the gas to retain to a substantial degree its original force upon injection into the headspace and thus may be injected into the furnace at a safe distance from the molten metal surface while still achieving substantially complete penetration into the molten metal.

Abstract: A melt treatment apparatus is provided which obviates an increase in floorspace and in cost and has freedom from a danger of steam explosion and further can control melt discharging with reliability.The welt treatment apparatus 1 is constructed with a furnace body 8 for entry of a material 17 to be heated, a plasma torch 2 that generates a plasma arc 13 so as to melt the material, a melt discharge passage 3 arranged in the furnace body for discharging a hot melt 14 derived by melting the material with the use of the plasma torch, and cooling gas jet means 7 disposed in the melt discharge passage and jetting a cooling gas to cool the hot melt to thereby form a dam 12.

Abstract: A plasma arc waste treatment furnace is equipped with a plasma arc torch having an electrode formed from a conductive refractory material. The refractory electrode can be operated at very high temperatures and does not need to be water-cooled. This eliminates a need for de-ionized water used in prior art furnaces. Arc erosion takes place very slowly and this results in long operating intervals of the furnace between shutdowns needed for electrode replacement. The electrode can be successfully operated as a cathode and this mode of operation improves melting efficiency.

Abstract: Method of heating molten metal in a tundish by irradiating a plasma torch on molten metal flowing along an internal surface of a heating compartment, and tundish configured for such method.

Abstract: A method for heating and/or melting a charge such as aluminum in a furnace using heat generated by combustion to radiatively heat the charge through a layer of protective gas wherein combustion reaction products generated by the combustion are exhausted from a lower level within the furnace, and, during melting, the protective gas layer has a higher upper boundary than during a subsequent heating period, enabling reduced NO.sub.x generation, lower fuel and oxygen consumption and reduced refractory corrosion by avoiding furnace gas flow through the high temperature upper furnace region.

Abstract: This invention discloses a method and an apparatus for gasification and vitrification of ashes, such as produced in a hog-fuel fired boiler, by means of a plasma arc. The ashes are introduced into a shaft furnace where two or three tiltable electrodes are located. The plasma arc is ignited between these electrodes which are then tilted from a horizontal to an essentially vertical position whereby the arc is lengthened and then broken into separate arcs, one between each electrode and the slag accumulated at the bottom of the furnace. This plasma arc helps to burn off the organics in the ashes, producing combustion gases that can be used as a source of energy for the boiler, and to keep the slag in molten state, which allows its periodic removal through a tap hole.

Abstract: Melting method for an electric arc furnace with alternative sources of energy for the melting of iron-based alloys, the electric furnace (10) including tuyeres (13) positioned on the bottom to deliver oxygen, at least one tuyere (15) to deliver coal dust which works in the area of contact between the bath of molten metal (16) and the layer of slag (22), at least one supersonic lance (12) cooperating with a lance (29) to deliver coal dust, these lances (12, 29) having a working position (12c, 29c) in which the supersonic lance (12) is positioned in close proximity to the surface of the molten metal (16) and the lance (29) to deliver coal dust is positioned in the vicinity of the surface of the layer of slag (22), and a plurality of burners (28) positioned on the cooled sidewalls (31) of the furnace (10) and delivering oxygen-based gases and combustible substances, whereby at least two first burners (28) work with the action of one burner supporting the action of the next one, the furnace (10) being charged wit

Abstract: Method and apparatus for the disposal of waste including a rotary kiln comprising at least one, and preferably a plurality of plasma guns positioned within a chamber defined by the rotary kiln, and at least one target electrode which is rotatable. One preferred embodiment of the present invention comprises a portable waste disposal unit wherein a rotary kiln, at least one plasma gun and a movable target electrode are advantageously positioned on a truck for ready transportation to a waste site.

Abstract: The present invention provides a relatively compact self-powered, tunable waste conversion system and apparatus which has the advantage of highly robust operation which provides complete or substantially complete conversion of a wide range of waste streams into useful gas and a stable, nonleachable solid product at a single location with greatly reduced air pollution to meet air quality standards. The system provides the capability for highly efficient conversion of waste into high quality combustible gas and for high efficiency conversion of the gas into electricity by utilizing a high efficiency gas turbine or by an internal combustion engine. The solid product can be suitable for various commercial applications. Alternatively, the solid product stream, which is a safe, stable material, may be disposed of without special considerations as hazardous material.

Abstract: The apparatus of the present invention is a melter housing having a pretreat chamber heated with a feed material heater that is partially isolated from a melter chamber. The method of the present invention has the steps of introducing feed material into a pretreat chamber and heating the feed material to a softening temperature of the feed material, and passing the pretreated feed material to a melter chamber.

Abstract: A waste-melting furnace includes a furnace body, a rotary heat-resistive vessel which is arranged inside the furnace body and into which waste is to be fed, and a transferred arc type torch plasma gun and a water-cooled electrode arranged above the rotary heat-resistive vessel, the plasma gun and electrode being opposed to each other.

Abstract: An aluminum melting method wherein an atmosphere above the aluminum charge is comprised of two strata, a lower strata covering the aluminum charge comprised of a non-oxidizing gas and an upper strata comprised of combustion gases from one or more burners. Heat from the burner or burners radiatively heats and melts the aluminum while the lower strata protects the aluminum from oxidative effects which would result if the aluminum surface were contacted with the combustion gases, thus serving to reduce dross formation.

Abstract: A plasma arc melter which is equipped with at least two transferred arc plasma torches of opposite polarities is used to melt normal batch materials for producing glass, ceramics, refractories and other such materials and for the recycling, combustion and/or vitrifying incineration of waste materials. To enhance the stability of the plasma jets, the anode torch is positioned farther above the surface of the materials being processed than the cathode torch and the materials being processed are introduced into the melter so that the materials first pass beneath the cathode torch. An oxidizing gas can be introduced into the zone between the torches in the region of the plasma jets to enhance the combustion process. For waste materials with a high organic content, a plasma arc afterburner can be used to further treat the exhaust gases from the melter.

Abstract: An ignitable material is positioned in contact with a slag contained within a plasma arc treatment system having an electrode and an electrical ground. The slag is initially at a temperature below a conducting temperature at which the slag will conduct electricity between the electrode and grounding network. The ignitable material has a self-sustaining reaction which releases heat energy upon ignition. The ignitable material is ignited with a pilot arc thereby heating at least a portion of the slag to the conducting temperature so that an arc between the electrode and grounding network can be sustained.

Abstract: A converter for the production of steel from solid and/or liquid charging substances, such as pig iron and/or scrap and/or sponge iron, includes a refractorily lined refining vessel, a refining device for feeding oxygen or an oxygen-containing gas, and a heating device. In order to obtain the maximum output possible at high scrap charging as well as a high purity of the steel, the heating device includes at least one self-consuming graphite electrode and the refining device, independent of the heating device, either is formed by an oxygen-blowing lance or includes oxygen-containing bottom and/or lateral tuyeres located below the melt bath level.

Abstract: The invention is directed to a plasma torch which projects into a container and is fastened at a supporting device and has a nozzle arranged at a burner lance, as well as a main electrode pipe with a main electrode arranged inside the burner lance, gaseous and liquid media as well as electric current being supplied to the main electrode via coaxially arranged pipes. An annular insulating member (21) is provided around the main electrode (10) in the region of its foot end and encloses the electrode (10) annularly, the casing (33) of the double-walled burner lance (30) which is held by the supporting device being fastened at this insulating member.

Abstract: An arc is drawn between a movable electrode (E) (preferably graphite), and a fixed electrode (7) in a furnace when smelting metal oxides using a plasma. Shielding gas, e.g. N. is introduced into plenum (P) about the movable electrode (E) to prevent metal vapor from settling on the inner lining (3;9) of the furnace (1). The movable electrode (E) may be connected to a mast (30) on the furnace roof (4) to align that electrode (E) in its path through a hole (10) in the roof (4) into the furnace chamber (C).

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: A system and method are provided for the non-thermal destruction of hazardous waste material using an electrodeless inductively coupled RF plasma torch. The waste material is combined with a controllable source of free electrons, and the RF plasma torch is used to excite the free electrons, raising their temperature to 3000.degree. C. or more. The electrons are maintained at this temperature for a sufficient time to enable the free electrons to dissociate the waste material as a result of collisions and ultraviolet radiation generated in situ by electron-molecule collisions. The source of free electrons is preferably an inert gas such as argon, which may be used as both the waste material carrier gas and the torch gas.

Abstract: A method and apparatus for forming a stream of molten material. The apparatus includes a melt container having a bottom wall in which is formed an aperture. A funnel is adapted and constructed to receive molten material from the aperture in the container, and includes a plurality of fluid-cooled metallic segments. The funnel segments define an inner funnel contour that decreases in cross-sectional area from the inlet end to the outlet end of the funnel. An electrically conductive coil surrounds the funnel, and has a shape corresponding to the outer shape of said funnel. A source of medium-frequency current in selective electrical connection with the coil. The method begins with the step of providing a predetermined quantity of molten material in a melt container. A metallic funnel is provided in fluid communication with the melt container, and includes a plurality of fluid-cooled funnel segments. The method also includes the step of providing an electrically conductive coil surrounding the funnel.

Abstract: Chemical waste is burned in oxygen using an electric plasma flame to heat a stream of gas which contains at least 70% by weight oxygen. Liquid waste in fine droplet form is introduced into the gas stream via a two-fluid atomizer using a carrier gas also preferably oxygen. The total amount of oxygen present is at least 30% more than required for complete combustion of the liquid waste. The reaction mixture is maintained at a temperature of at least 1450.degree. C. for a time of at least 2 milliseconds prior to cooling rapidly of the reaction products to a temperature below 300.degree. C.

Abstract: A furnace bottom structure of a direct current electric furnace has at least one furnace bottom electrode and at least one gas injection tuyere provided in the furnace bottom refractory of the direct current electric furnace. Preferably, the furnace bottom electrodes and the gas injection tuyere are embedded in a substantially cylindrical refractory body with downwardly diverging tapered upper portion. The refractory body, the furnace bottom electrodes and the gas injection tuyere form an integral furnace bottom block which is detachably attached to the bottom of the electric furnace so as to close a bottom opening of the furnace.

Abstract: A method of preparing a melt for mineral fibre production wherein a mixture of mineral fibre-forming raw materials is introduced into a shaft furnace and is heated to melting temperature by a plasma gas stream formed in a plasma torch and wherein waste material from mineral fibre production is introduced into the plasma gas stream by a rotatable screw conveyor mounted in a feed pipe, the melt formed in the shaft furnace is being discharged from the bottom of the furnace and passed to a fiberizing apparatus in which it is converted into mineral fibres.

Abstract: A method of producing finely divided particles or powder, vapor or fine droplets comprises the steps of heating and melting the starting raw material in a vessel having opposed reflecting surfaces, and ejecting the melted raw material from the vessel as heated finely divided particles or powder, vapor or fine droplets, by introducing a carrier gas into the vessel.

Abstract: A high temperature reaction apparatus and method employing radiation to heat and react on matter, such as one or more fluids containing one or more reaction materials in gaseous molecular and/or particulate form. In a preferred form, one or more high temperature plasmas as formed across one or more pairs of electrodes which define a single or a plurality of plasmas and a single or plural reaction zones. A stream or streams of fluid particles pass through such reaction zone or zones and all or select of the particles or molecules thereof are heated to a high temperature sufficient to effect a select chemical and/or physical reaction or a plurality of high temperature reactions involving a plurality of reaction products which are separated from each other downstream of the reaction zone or zones. The apparatus and a method may be used to separate select atoms from molecules of a gas or gases passed through the reaction zone or zones by breaking the bonds between the atoms of the molecules of the gas.

Abstract: A furnace for producing a melt for mineral wool production includes a shaft for preheating and melting of the raw material. A water-cooled grate is disposed in the bottom portion of the shaft, which supports a bed of ceramic filling bodies as well as the raw material. A combustion chamber is disposed underneath the shaft, which has a bottom portion for collecting the melt dripping from the shaft and an outlet for melt tapping. At least one main burner is disposed in the combustion chamber. Auxiliary burners are disposed above the grate. The bottom surface of the combustion chamber is larger, preferably 20 to 400% larger, than the transverse cross-sectional area of the shaft.

Abstract: A process for the treatment of a continuous or perturbated stream of liquid material, which process consists essentially of passing the said stream of liquid material through a plasma arc coupling zone in which at least two plasma arcs are coupled at the surface of the liquid stream in order to raise both the bulk temperature of the stream and the temperature of the outer surface of the stream of material, thereby to effect a treatment of the stream selected from thermal, chemical, and a mixture of thermal and chemical.

Abstract: Apparatus and method for the disintegration of waste by subjecting the waste within a closed chamber to plumes of an electrically generated high temperature plasma. The chamber is lined with an array of nozzles to produce the plumes and the nozzles are supplied with a cooling gas at all times. The nozzles are energized to produce the plumes in a predetermined sequential manner so that the waste is destroyed in steps, or bites. The gas containing the products of disintegration is withdrawn and filtered. One embodiment comprises a portable device capable of disintegrating waste over a large area such as at a waste dump site.

Abstract: In a method for the preparation of a melt for the production of mineral wool a raw material is introduced at the top of a shaft furnace and heated to melting temperature partly with a hot gas formed by plasma heating and partly with a hot gas formed by combustion of one or more gaseous hydrocarbons, the latter gas stream being introduced at a level at which the temperature does not exceed 1250.degree. C., and the melt formed is discharged at the bottom of the shaft furnace.

Abstract: Disclosed is a plasma reactor for use to treat ores or other material at a very high temperature in order to physically or chemically transform the same. The reactor comprises a vertical, electrically insulated sleeve disposed at the upper end with a hollow torch of a conventional structure, for use to generate a plasma column. A gas is tangentially injected into the torch to create a vortex inside the same. The material to be treated is dropped, in powder form, vertically downward inside the sleeve from the upper end thereof, beside the hollow torch, so as to form a substantially uniform cylindrical curtain of particles falling down into the sleeve. The particles that are centrifugally projected against the internal wall of the sleeve by the vortex escaping from the hollow torch, entirely cover the internal wall of the sleeve and shield, while simultaneously being treated by heat generated by the plasma arc column.

Abstract: A silicon smelting furnace and a process for utilizing this furnace for the production of silicon is described. The process involves a process in which equilmolar proportions of silicon carbide and silicon dioxide are charged to the reaction zone of a silicon furnace. Above the furance is placed a shaft containing particulate carbon in the amount of 2 moles of carbon per mole of silicon dioxide charged to the reaction zone. As energy is applied to the reaction zone, molten silicon, gaseous silicon monoxide, and gaseous carbon monoxide are formed, the gases passing through the shaft of carbon, converting the carbon to silicon carbide. The silicon carbide, so formed, is combined with an equimolar proportion of silicon dioxide, and the cycle is repeated. Aside from an initial charge of silicon carbide, the feeds to the smelting furnace are silicon dioxide and carbon, silicon carbide being formed concurrently in a bed of carbon separated from the furnace reaction zone during the smelting cycle.

Abstract: A method for melting iron and steel scrap wherein scrap is fed through a shaft furnace countercurrent to a reducing gas. The reducing gas is formed by passing air through a plasma generator and injecting coal and/or hydrocarbon into the hot air so that the ratio (CO.sub.2 +H.sub.2 O)/(CO.sub.2 +H.sub.2 O+CO+H.sub.2) of the resulting gas becomes less than 0.2. The energy needed for melting is supplied as sensible heat of the reducing gas. The energy for preheating the scrap is supplied by introducing oxygen containing gas into the preheating zone at a plurality of positions along the flow path of the reducing gas to provide stepwise combustion of the reducing gas. The introduction of the oxygen containing gas at said plurality of positions is balanced to keep the gas reducing to the metal scrap at scrap temperatures above 1000.degree. C., and preferably even above 800.degree. C.

Abstract: Method for melting or melt reducing chemical mixtures at temperatures which exceed the melting temperatures of highly-refractory linings. The method requires the steps of pressing the chemical mixture into bars and arranging the bars to form a cavern having a defined geometry. The cavern surrounds a centrally located high energy density radiation source. The portion of the bar facing the radiation source melts at a certain melting rate. The cavern geometry is maintained by radially advancing the bars toward the radiation source at the same rate as the melting rate.