Abstract: Insulating members are provided for use in nozzles of elevated temperature process vessels employing a structural metal shell (24), an insulating refractory lining (14) and a corrosion-resistant membrane (18) lining between the structural shell and refractory lining. The insulating members comprise pre-formed insulating sleeves and inserts and are made of a thermally insulating material having sufficient thickness and sufficiently low thermal conductivity such that, when the sleeve or insert is heated by the process temperature during operation of the vessel, the thermal energy transmitted through the sleeve or insert to the membrane is insufficient to raise the temperature of the membrane above a target temperature. The most preferred thermally insulating materials are fluoropolymers such as poly(tetrafluoroethylene) flouropolymer resins.

Abstract: Some embodiments of the present invention provide systems, methods and apparatus for more accurately determining the thickness of a refractory lining included in an operating metallurgical furnace. Specifically, in some embodiments a transient propagated stress wave is used to determine the condition of a refractory lining, and additionally, provide a systematic way to include the affect that temperature has on the velocity of a compressive wave through a heated refractory material and/or accretions. As identified in aspects of the present invention, and contrary to the common understanding in the art, the velocity of a stress wave, at each frequency and in a refractory material, is not necessarily constant over a temperature range. In accordance with aspects of some specific embodiments of the invention, a scaling factor ? can be calculated for each refractory material to adjust for the presumed velocity of the stress wave through each refractory material.

Abstract: Aspects of the invention relate to methods and systems for predictive electrode lowering in an electric furnace. According to one aspect, there is provided a method comprising: monitoring an operating parameter of a variable reactance circuit; comparing the operating parameter with a threshold value; and lowering an electrode coupled to the variable reactance circuit if the operating parameter meets or passes the threshold value. The operating parameter may be a current threshold. The current threshold may be determined based on at least one of: a predetermined proportion of an expected total current through the variable reactance circuit; a primary supply voltage; a rated reactance value of the parallel inductor; and a target power factor. The current threshold may be in the range between about 10% and 60% of the expected total current through the variable reactance circuit and may vary proportionally with the primary supply voltage.

Abstract: A method and system for stabilizing energy consumption in multiple loads, or in single multi-phase loads. The method and system also compensates for unbalance in multi-phase loads. A central controller monitors variable reactances in the loads and identifies situations of power and/or current fluctuation and/or unbalance. It determines appropriate corrective action by the other loads/phases to compensate for the power and/or current change or unbalance due to the problematic load, and it issues control signals instructing variable reactor controllers associated with the other loads to adjust accordingly. The method and system may by applied to electric arc furnace installations. An electrode position controller may be used in place of, or in conjunction with, the variable reactance control system to take corrective action to address power and/or current changes or unbalances. The system and method may be employed to maintain a predetermined level of unbalance in the system.

Abstract: The described methods and systems may be applied to electric arc furnace installations. In this context, the method and system provide an electrode position controller coupled to the feed rate controller so as to predictively anticipate the introduction of new source material and lower the electrodes so as to prevent arc extinguishment while variable reactors are controlled to maintain predetermined power set-points. The electrode position controller may be used in place of, or in addition to, the variable reactance control system to take corrective action to address power and/or current changes or unbalances.

Abstract: Embodiments of the invention generally relate to needles having more than one electrode and which are particularly suited for use in electromyography. One embodiment relates to a tripolar needle having three concentric electrodes. The tripolar needle is formed by providing a needle blank having first and second concentric electrodes and forming a third concentric electrode around the needle blank. The tripolar needle has an outer diameter which is substantially constant along the shaft of the needle, except at the tip, where the needle is sharpened.

Abstract: A method and system for stabilizing energy consumption in multiple loads, or in single multi-phase loads. The method and system also compensates for unbalance in multi-phase loads. A central controller monitors variable reactances in the loads and identifies situations of power and/or current fluctuation and/or unbalance. It determines appropriate corrective action by the other loads/phases to compensate for the power and/or current change or unbalance due to the problematic load, and it issues control signals instructing variable reactor controllers associated with the other loads to adjust accordingly. The method and system may by applied to electric arc furnace installations. The system and method may be employed to maintain a predetermined level of unbalance in the system.

Abstract: A method and system for stabilizing energy consumption in multiple loads, or in single multi-phase loads. A central controller monitors variable reactances in the loads and identifies situations of power and/or current fluctuation and/or unbalance. The central controller determines appropriate corrective action by the other loads/phases to compensate for the power and/or current change or unbalance due to the problematic load, and it issues control signals instructing electrode position controllers associated with the other loads to adjust accordingly. The method and system may by applied to electric arc furnace installations. The electrode position controllers may be used in conjunction with variable reactance control systems to take corrective action to address power and/or current changes or unbalances. The variable reactors respond orders of magnitude faster than the electrode positioning system.

Abstract: A method and system for stabilizing energy consumption in multiple loads, or in single multi-phase loads. The method and system also compensates for unbalance in multi-phase loads. A central controller monitors variable reactances in the loads and identifies situations of power and/or current fluctuation and/or unbalance. It determines appropriate corrective action by the other loads/phases to compensate for the power and/or current change or unbalance due to the problematic load, and it issues control signals instructing variable reactor controllers associated with the other loads to adjust accordingly. The method and system may by applied to electric arc furnace installations. In this context, the method and system provide an electrode position controller coupled to the feed rate controller so as to predictively anticipate the introduction of new source material and lower the electrodes so as to prevent arc extinguishment while the variable reactors maintain predetermined power set-points.

Abstract: A binding system for applying a vertical compressive force to the refractory walls of a rectangular or circular furnace comprises a compressive member engaging a laterally extending surface of the furnace wall and a support member to which the compressive member is connected. The compressive member preferably comprises a coil spring which acts directly on the laterally extending surface or indirectly through a force-applying member. The force applied by the compressive member is sufficient to control vertical expansion and substantially prevent vertical expansion of the furnace walls due to infiltration of material into the joints between the refractory bricks during operation of the furnace.

Abstract: A system is disclosed for lowering (“slipping”) and/or raising (“back slipping”) electrodes relative to an electrode column. The system includes an electrode column having at least one slipping sleeve and a power clamp, each of which apply a radial clamping force to the electrode. The magnitudes of the clamping forces are selected such that application of a downwardly directed axial force on the one or more slipping sleeves, in combination with the weight of the electrode, are sufficient to overcome the resistive force of the power clamp, resulting in downward movement of the electrode without release of the clamping forces. Electrode columns having two movable slipping sleeves are also capable of raising the electrode relative to the furnace without release of the clamping forces.

Abstract: Apparatus for transferring hot material between a preprocessing plant and an electric furnace has an enclosed housing extending between the plant and the furnace and within which a controlled atmosphere is maintained, at least one bin having at least one compartment receiving feedstock material at a delivery station from the plant, mechanism for shuttling the at least one bin along a path within the housing between the delivery station and discharge tubes above and leading into the furnace at distributed locations, and discharge mechanism for dropping material from each compartment into a discharge tube. The path may be horizontal, vertical, or inclined to suit the relative locations of the preprocessing plant and the battery. Each bin is usually each divided to feed multiple tubes. The shuttling mechanism may be a hoist or a railway or cable span, and the discharge mechanism is typically a means for tipping the bin.

Abstract: A process for the manufacture of steel in which a charge material comprising direct reduced iron, and optionally containing steel scrap, is continuously charged into a stationary electric arc furnace. Inside the furnace, a bath of molten steel and a continuous slag layer are maintained, the steel bath preferably having a volume of approximately 7 to 13 tap volumes. Heat for melting the charge material is preferably provided by open arcs between the electrodes and the metal bath, with the slag layer preferably being superheated to about 40 to 150° C. above the bath temperature. In order to prevent excessive superheating, the slag preferably has a melting point substantially the same as, or greater than, the bath temperature, with the slag melting temperature being adjustable by varying the amount of MgO in the slag. The slag preferably has low basicity to reduce the rate of refractory erosion.

Abstract: A process and apparatus for recovering a metal from a feedstock containing a compound of the metal. The process includes an electrowinning step in which a leachate comprising a salt of the metal, dissolved in an aqueous acid solution, is subjected to electrowinning in an electrolytic cell, wherein elemental metal is deposited on the cathodes of the cell and oxygen is generated at the anodes. The oxygen generated at the anodes is collected and is then at least partially consumed in an oxygen-consuming step of the process. Preferably, the oxygen-consuming step comprises an atmospheric or pressure leaching step in which the metal compounds in the feedstock become dissolved in a leachate in the form of metal salts, preferably sulfates. The recovery and use of anode oxygen in a leaching process encourages the use of mist-reducing technology in existing and new electrowinning facilities.

Abstract: A system for supporting and cooling a furnace roof comprised of refractory bricks comprises a plurality of roof support members extending across the furnace and being supported from above the furnace roof. The support members are provided with internal channels for circulation of a cooling fluid, and are provided with side surfaces adapted to support rows or refractory bricks between adjacent roof support members. The system eliminates the need to suspend individual bricks from above the roof, and provides simultaneous support and cooling of the roof structure.

Abstract: A process is disclosed for regenerating an aqueous acid halide leachant from a spent aqueous metal halide leach liquor. The process comprises introducing into a fluidized bed or spray roaster a hydrocarbon fuel, an oxygen-enriched oxidizing gas and the aqueous metal halide leach liquor; pyrohydrolyzing the aqueous metal halide leach liquor by combustion of the hydrocarbon fuel with the oxygen-enriched oxidizing gas to produce an acid halide-containing gas fraction and a metal oxide-containing solid fraction; separating the gas fraction from the solid fraction, recovering heat energy from the acid halide-containing gas fraction and absorbing the gas fraction in water to produce the aqueous acid halide leachant. The oxygen-enriched oxidizing gas has an oxygen concentration of greater than about 21 percent by volume, preferably greater than about 50 percent by volume, more preferably greater than about 80 percent by volume, and even more preferably greater than about 90 percent by volume.