Abstract: A method and composition for removing sulfur from molten ferrous material, particularly molten iron. The desulfurization agent includes one or more pucks or briquettes of deoxidizing and/or desulfurization agent. The pucks or briquettes of deoxidizing and/or desulfurization agent include at least one deoxidizing metal and at least one ferrous metal.

Abstract: Chrome-containing molten iron and slag are to be obtained in an electric furnace operation using CaF2-free slag. In order to reduce and collect chrome from the slag while simultaneously promoting desulfurization of molten iron, a chrome-containing molten iron produced in an electric furnace and having a Cr content of from 8.0 to 35.0% by mass, and a CaF2-free electric furnace slag formed during the molten iron production, including Cr2O3, SiO2 and CaO as the constituent components and having a basicity CaO/SiO2 of from 0.7 to 1.7, are mechanically stirred with an impeller in a refining vessel. A metal Al-containing substance and CaO are put into the vessel before the end of stirring to thereby control the basicity of the slag after the end of stirring to at least 1.

Abstract: A method for stirring chrome-containing molten iron comprises mechanically stirring chrome-containing molten iron contained in a refining vessel by the use of an impeller having a rotation axis in the vertical direction where the refining vessel is such that the horizontal cross section of the inner wall thereof is circular around the central axis of the vessel in the vertical direction and the impeller, as integrated with the axial rod covered with a refractory, rotates around the central axis of the axial rod, as the rotation axis thereof. The stirring mode is regularly or irregularly switched between a concentric stirring of the molten iron in a state where the rotation axis of the impeller is centered in the central axis of the vessel and an eccentric stirring of the molten iron in a state where the rotation axis of the impeller is decentered from the central axis of the vessel.

Abstract: A method of desulfurizing steel including steps of forming a slag over a molten metal, drawing a vacuum to less than 5 torr over the slag and molten metal, stirring the molten metal and slag, and deoxidizing and desulfurizing the molten metal and slag to degas the steel reducing at least sulfur, nitrogen, oxygen, and hydrogen contents, and reducing activity of oxygen in the molten metal to less than 30 ppm. The method includes forming a slag composition after degassing the steel comprising CaO between about 50 and 70% by weight, SiO2 between about 20 and 28% by weight, CaF2 between about 5 and 15% by weight, MgO not more than 8% by weight, Al2O3 not more than 1% by weight, and a combination of FeO+MnO not more than 2% by weight, where the sum of CaO+CaF2+SiO2+MgO is at least 85% by weight.

Abstract: Chrome-containing molten iron and slag are to be obtained in an electric furnace operation using CaF2-free slag. In order to reduce and collect chrome from the slag while simultaneously promoting desulfurization of molten iron, a chrome-containing molten iron produced in an electric furnace and having a Cr content of from 8.0 to 35.0% by mass, and a CaF2-free electric furnace slag formed during the molten iron production, including Cr2O3, SiO2 and CaO as the constituent components and having a basicity CaO/SiO2 of from 0.7 to 1.7, are mechanically stirred with an impeller in a refining vessel. A metal Al-containing substance and CaO are put into the vessel before the end of stirring to thereby control the basicity of the slag after the end of stirring to at least 1.

Abstract: A method for stirring chrome-containing molten iron comprises mechanically stirring chrome-containing molten iron contained in a refining vessel by the use of an impeller having a rotation axis in the vertical direction where the refining vessel is such that the horizontal cross section of the inner wall thereof is circular around the central axis of the vessel in the vertical direction and the impeller, as integrated with the axial rod covered with a refractory, rotates around the central axis of the axial rod, as the rotation axis thereof. The stirring mode is regularly or irregularly switched between a concentric stirring of the molten iron in a state where the rotation axis of the impeller is centered in the central axis of the vessel and an eccentric stirring of the molten iron in a state where the rotation axis of the impeller is decentered from the central axis of the vessel.

Abstract: Disclosed is a mixing, milling, and aeration apparatus for the digestion of metal ore with bacteria. It includes a tank and a center post therein. At least one mixing blade extends radially from the center post. At least one roller is supported by a mixing blade, where each roller is configured to roll about the center of the tank while applying a crushing force to solids within the tank. At least one gas distributor, supported by a mixing blade, defines a plurality of holes through which gas is distributed to encourage mixing of the contents of the tank, to encourage distribution of oxygen through the contents, and to discourage fouling of the bottom of the tank and the rollers.

Abstract: The invention provides an improved furnace structure and methods of melting material in furnaces, particularly aimed at reducing the start up time for such furnaces. The furnace (2) defines a container for the molten metal having a maximum depth of molten metal in that container during use. A flow generator (30) for the molten metal within the furnace is fed through a first conduit (32) and supplies material back to the furnace through a second conduit (36). The first conduit entrance is provided in the upper 60% of the maximum depth of the molten metal in the container and/or the second conduit exit is provided in the lower 25% of the maximum depth of the molten metal in the container. The flow generator may receive material preferentially from around the periphery of the container and/or direct material towards the centre of the container. The inlet and outlet to the flow generator may be angled downwards towards the container.

Abstract: A battery of stationary hearth furnaces, and method for using, for producing metallic iron nodules having a furnace having a stationary hearth, an inlet and an outlet; a heating chamber beneath the stationary hearth having heated fluids circulated thereto and heating reducible material on the stationary hearth; passageways circulating fluids, through ports from the furnace housing above the reducible material to the heating chamber beneath; burners and air inlets in the furnace and optionally in at least one passageway and a heating chamber for drying and heating the reducible material, driving off and burning volatile material, and forming metallic iron nodules; a loading device for loading reducible material and optionally hearth material onto the stationary hearth through the inlet; and a discharging device capable of discharging metallic iron nodules and optionally related material from the stationary hearth through the outlet.

Abstract: A process for stirring molten steel in a container. In this process, argon gas is introduced into the container at a flow rate of from about 0.005 to about 0.2 cubic feet of argon per ton of molten steel per minute, the extent to which said container is caused to vibrate is measured, analog signals are produced corresponding to the rate of flow of argon gas into said container, the analog signals are sampled at a rate of at least 800 times per second, the analog signals are converted to digital signals, the digital signals are transformed by subjecting them to fast Fourier transformation, and the transformed digital signals are evaluated.

Abstract: The charge well of a metal melting furnace is provided with an internal cavity having a circular cross section when viewed from the top, preferably a cavity of cylindrical or conical configuration, and with a peripheral exit port located tangentially with respect to said cavity at a lower level thereof for exit of molten metal into the main chamber of the furnace. An inert gas bubble-actuated molten metal pump brings molten metal from a hotter section of the furnace, advantageously directly from the main chamber, and has its exit port located tangentially to the periphery of the cavity at an upper level thereof, thereby creating vortical flow of molten metal within the charge well for the more rapid and efficient melting of metal chips and scraps into the molten metal therein and for circulation of hotter molten metal throughout the furnace.

Abstract: The invention disclosed herein utilizes magnetic forces to draw metal particles having magnetic characteristics into and beneath the surface of a molten metal stream flowing through a non-magnetic trough. The apparatus of the present invention includes a declined non-magnetic trough having an interior channel. Means are provided for introducing a molten metal stream into the trough. A magnetic source is provided which produces a magnetic field having flux lines which extend through the non-magnetic trough and to at least the surface of the molten metal stream. A particle discharge mechanism having contained therein substantially ferromagnetic metal particles is positioned above the surface of the molten metal stream. Gravity draws the metal particles onto the surface of the stream and the particles are drawn beneath the surface of the stream by the magnetic field.

Abstract: An inert gas bubble-actuated molten metal pump is located between one section of a metal-melting furnace and a second section to pump molten metal from the one section, wherein the molten metal is at a higher temperature, into the second section, wherein the molten metal is at a lower temperature, and its effluent is directed into contact with metal chips being charged into the second section, thereby assisting in the more rapid melting of the chips into the molten metal mass in the second section. The inert gas employed to actuate the molten metal pump is captured beneath a heat-resistant and flame-resistant cover located above the exit port of the pump and over a substantial portion of the molten metal mass in the second section, thereby providing a non-oxidizing atmosphere at the surface of the molten metal mass or pool beneath said cover.

Abstract: Both a method and apparatus for producing molten steel are provided wherein ferrous materials rich in carbonaceous materials are fused in a first vessel of a single electric furnace having separate first and second vessels. The carbonized molten metal thus obtained is then pretreated in a separate pretreatment facility to remove contaminants and the pretreated molten metal is then decarburized in the second vessel of the electric furnace. The decarburization of the pretreated metal in the second vessel of the furnace avoids reintroducing contaminants into the steel by avoiding contact between the pretreated metal and the slag produced when the initial carbonaceous materials are fused. Preferably, the first and second vessels are two vessels of a single electric furnace having a single electric power source.

Abstract: An improved impeller head is provided for treating molten metals and other liquid systems with a gas. A multiple-vaned impeller head is adapted for mounting on a hollow impeller shaft for rotation within the liquid The edges of the impeller vanes are extended by an axial groove which intercepts the hub and the vanes of the impeller head. Extension of the trailing edge of the vanes creates greater turbulence in the liquid as the impeller is rotated in the liquid and increases the impeller's efficiency. The impeller vanes may also have canted leading surfaces which create an upward axial flow of liquid to discourage formation of a surface vortex. Multiple impellers may also be mounted on a shaft in the vessel and the gas may be introduced remotely.