Abstract: In accordance with an example embodiment of the invention, a three-phase power control device is configured to synchronize firing thyristor or SCR sets in consecutive combinations of two of the three phases, to supply current to consecutive combinations of two of the three loads in a three-phase load configuration, to determine real branch impedance of each load from three combinations of two supplied loads, without need of any electrical neutral reference.

Abstract: The disclosure provides a slag wool composition including about 60 to about 80 wt. % blast furnace slag and about 20 to about 40 wt. % basalt, based on the total weight of the inorganic raw materials, wherein the composition has an A/B ratio in a range of about 1.20 to about 1.70. The disclosure further provides a slag wool produced using the slag wool composition of the disclosure, wherein the slag wool has a fiber diameter in a range of about 4.0 microns to about 10.0 microns. The disclosure further provides a method for the manufacture of slag wool.

Abstract: A glass melting tank comprising at least one front part for introducing the charge material, and at least one charging device. To reduce atmospheric heat losses and reduce dust transport into the upper furnace of the tank, and nevertheless to intensify the heating of the charge material, the front part has a length “LV” of at least 2,250 mm in the direction of the melting tank, and a length “LG” of at least 1,200 mm is provided with an insulating roof. An end wall near the charging device, together with the roof, encloses a gas chamber open toward the melting tank. A characteristic value “K” of 3.50 tonnes (t) per hour and per square meter of surface is not exceeded. The characteristic value is calculated from P/F, where P is the throughput per hour in tonnes (t) and F is the inner surface of the front part in m.

Abstract: Provided herewith is a method for preheating a glass mixture to be fed into a glass furnace. The method comprises separately preheating at least some of the materials which comprise the load, and then subsequently remixing the preheated materials and passing the load to the glass furnace.

Abstract: In a glass melting furnace, a radiation screen wall is installed between a melting area and a refining area with a refining bank. This radiation screen wall leaves a flow path above the melt surface of the glass bath for the return flow of at least part of the combustion gases from the refining area to the melting area. In order to suppress a return flow of already refined and very hot glass melt from the refining area into a melting area, but still allow the charging material to melt completely as early as possible, the furnace is operated to produce at least one upward current between the middle of the melting area and the front face of the refining bank in the glass melt.

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 method and apparatus for vitrifying waste materials containing a high quantity of carbon are provided which include the use of a secondary combustion chamber for burning the waste gases resulting from an electrically heated glass melting furnace. Additional energy is generated by this afterburning which is used to preheat batch materials used in the glass melting furnace. The particulate matter in the burned waste gases is collected in a gas washer as sludge, is thickened, and is fed back to the glass melting furnace.

Abstract: For obtaining mineral fibers from a thermoplastic material having a high melting point, and more precisely for the regulation of the flow rate and temperature of the stream of molten material distributed on the fiber-drawing machine, the molten material is conveyed via a reservoir where the flow rate is regulated and the height of the molten material at the base of the tapping aperture is controlled by inclining the reservoir. Preferably the molten material is subject to a basic heating process which raises its temperature close to the fiber-drawing temperature and, in the vicinity of the tapping aperture, it is subject to additional heating in order to adjust the temperature precisely.

Abstract: An apparatus for processing various hazardous waste materials by melting in a vessel for subsequent solidification is disclosed which includes a seal for the cover thereof. Melter includes a high-speed mixing impeller powered by a drive shaft which extends through an opening in the cover. The vessel is electrically heated by discharge of electrical energy through the melt contained in the vessel. In one embodiment the impeller and shaft are included in the electrical heating circuit. A shaft seal engages the shaft at a point spaced from the cover. An axially extensible seal seals a space bounded by the shaft seal and the opening in the cover. Purge gas is supplied to the sealed space to provide positive gas flow from the sealed space into the vessel. A cold wall transport duct for off-gas porting is disclosed. A bottom drain structure including a sleeve and plug is also disclosed. The output of the melter may be subsequently heated in a holding tank to refine the output.

Abstract: A melting furnace for treating wastes is provided which has a container equipped with a feed port for a glass raw material and wastes to be treated at the top thereof and a discharge port for molten glass containing said wastes at the bottom thereof, the container having a wall made of a heat resistant alloy and the container wall being in contact with molten glass inside the container; a heating electrode disposed in the container, the container wall acting as a counter electrode for the heating electrode; and a cooling system disposed at the back side of the container wall. By directly supplying electric power to the glass means disposed at the back side of the container wall.By directly supplying electric power to the glass between the container wall and the heating electrode, the molten glass containing the wastes can be formed. By conducting cooling of the container wall by the cooling system, corrosion of the wall due to the atmosphere in the container can be restricted.

Abstract: A batch charger for a molten glass furnace comprising a stationary hopper having an inlet opening at the upper end and an outlet opening at the lower end. A reciprocable charger plate located below the outlet opening of the hopper to supply material from the hopper to the furnace. The charger plate has a bottom wall and upstanding sidewalls at the edges of the bottom wall which are outwardly spaced from the sidewalls of the hopper. An adjustable seal is attached to the rear wall of the hopper with a lower edge located below the lower edge of the rear wall of the hopper and depending flapper members are pivotally attached to the front wall of the hopper at each edge to prevent loose material from passing between the sidewalls of the charger plate and the sidewalls of the hopper when the charger plate is reciprocated.

Abstract: A method of feeding glass to a glass-melting furnace for making a vitreous material, a heated airstream containing air at a temperature in excess of 1,000.degree. C. is passed down vertical cylinders towards the crown of the glass-melting furnace. Powdered glass batch is introduced into the vertically moving heated airstream in the lower and wider cylinder and infra-sound is applied to the vertically moving heated airstream by an infra-sound generator to vibrate the heated airstream and effect heat transfer from the airstream to the glass batch particles so that the glass batch particles are heated and the temperature of the heated airstream is reduced to a temperature below 700.degree. C., thereby reducing the propensity of the air to produce nitrogen oxides.

Abstract: A method and apparatus for feeding iron-bearing particles into a metallurgical furnace such as an electric arc furnace, comprising a vessel for containing a bath of molten iron, having a wall extending above the bath of molten iron, a preferably screw type feeder mounted on the exterior of the vessel, a feeding port in the vessel wall shaped to permit passage of the feeder into the interior of the bath of vessel and located at such a height from the molten iron so that no molten materials will spill out from the furnace through the port during the normal operation and maneuvering of the furnace; and actuating means for extending the screw type feeder from a retracted position out of the vessel to an extended position into the vessel.

Abstract: A method for thermal decomposition treatment of a radioactive waste uses an apparatus comprising a container for holding molten matter of a radioactive waste containing a sodium compound, a pair of electrodes contacting the molten matter, and a power source for applying voltage between the electrodes while changing the polarity thereof every several tens of seconds. In this apparatus, the molten matter can be heated in the container by Joule heat, which is evolved by electric current directly flowed through the molten matter, so that the sodium compound contained in the radioactive waste can be decomposed, vaporized and removed to recover a stabilized radioactive solid as a residue in the container.

Abstract: Glass is made from a feed consisting of batch materials and cullet in a furnace that is both electrically and gas fired. A batch-only hopper discharges through a blanket conveyor to a batch melting chamber that is electrically fired and is connected via a submerged throat to a fritting chamber where the at least partly molten batch materials are mixed with cullet fed from cullet-only hoppers by blanket feeders. The fritting chamber is fired by a combination of electricity and roof-mounted flat flame burners. Material passes from the fritting chamber to a secondary reheating and refining chamber which is heated by regenerative gas burners. The separation of batch materials from cullet and separate melting thereof in a pre-melter means that the feed to the secondary refining and conditioning chamber is relatively free of fines and requirement to melt only cullet in the fritting chamber and secondary refining chamber enables those chambers to be operated at a lower temperature than the batch melting chamber.

Abstract: Disclosed is an improved efficiency glass melting furnace and a method of operation in which a mixture, or batch, is fed at a narrow side of a rectangular glass melting tank onto the molten glass mass (or bath) across the full width thereof. The furnace includes burners positioned adjacent to the opposite narrow side for supplying energy, and heat exchangers for energy exchange between the combustion exhaust gases and the combustion air supplied to the burners. The exhaust gas openings are disposed adjacent to the mixture feeding area. The furnace is provided with at least one thermal radiation shield between the burner and feed sections which extends to a small distance above the molten glass.

Abstract: Glass or the like is melted by liquefying batch materials in a first stage by means of radiant heating, and further advancing the melting process in a second stage where the melt is heated by induction heating. Another aspect of the invention provides a residence zone at the exit of the induction heating stage to aid elimination of gaseous inclusions.

Abstract: A reverberatory furnace for melting aluminum or other metals which includes a preheater (12) which utilizes exhaust flue gasses from the furnace (10) to preheat the metal before it enters the furnace. A set of horizontal flue ducts (18, 20, 22) conduct the flue gasses to a preheater chamber (26) where they heat the metal. An air entrance port (50) is provided in the preheater chamber (26) to allow secondary combustion of the volatile flue gasses for additional efficiency.