Patents Assigned to Iron Carbide Holdings, Ltd.
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Process for the production of iron carbide from iron oxide using external sources of carbon monoxide
Patent number: 6428763Abstract: The present invention is a process for the rapid conversion of iron oxide-containing material into iron carbide. The process includes a first step in which the iron oxide-containing material is contacted with a reducing gas that contains a high concentration of hydrogen gas to form a metallic iron-containing intermediate product and a second step in which the metallic iron-containing product is contacted with a carburizing gas having high concentrations of hydrogen and carbon monoxide gas to produce iron carbide. The unused carbon monoxide in the off-gas from the second step is not recycled to the second step but is used as a fuel source.Type: GrantFiled: March 22, 2000Date of Patent: August 6, 2002Assignee: Iron Carbide Holdings, Ltd.Inventors: Frank M. Stephens, Jr., Frank A. Stephens, Robert F. Hogsett, John P. Hager -
Patent number: 6328946Abstract: The present invention is a process for the conversion of iron-containing material into iron carbide. The process includes a first step in which the iron-containing material is contacted with a reducing gas that contains no more than a small amount of reactive carbon to produce metallic iron and a second step in which the metallic iron is contacted with a reducing and carburizing gas to produce iron carbide. The reducing and carburizing gas includes reactive carbon, hydrogen, and methane. The iron carbide product is of high purity.Type: GrantFiled: February 8, 1999Date of Patent: December 11, 2001Assignee: Iron Carbide Holdings, Ltd.Inventor: Frank M. Stephens, Jr.
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Patent number: 6165249Abstract: A process for producing iron carbide in a fluid bed reactor in which the pressure may be maintained in excess of the pressure at which the mole fraction of hydrogen in the process gas begins to decrease. The hydrogen concentration is increased above the equilibrium concentration for hydrogen at the temperature and pressure in the reactor. Further improvements are gained by preheating a iron ore reactor feed in which the iron oxide is primarily in the form of hematite under a reducing atmosphere, and using at least two fluid bed reactors in series.Type: GrantFiled: August 20, 1997Date of Patent: December 26, 2000Assignee: Iron Carbide Holdings, Ltd.Inventor: Arden W. Swanson
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Patent number: 5869018Abstract: The present in a process for the conversion of iron-containing material into iron carbide. The process includes a first step in which the iron-containing material is contacted with a reducing gas that contains no more than a small amount of reactive carbon to produce metallic iron and a second step in which the metallic iron is contacted with a reducing and carburizing gas to produce iron carbide.The reducing and carburizing gas includes reactive carbon, hydrogen, and methane. The iron carbide product is of high purity.Type: GrantFiled: January 14, 1994Date of Patent: February 9, 1999Assignee: Iron Carbide Holdings, Ltd.Inventor: Frank M. Stephens, Jr.
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Patent number: 5810906Abstract: The present invention provides a two-stage method for pretreating an iron oxide-containing feed material prior to conversion of the material into an iron carbide-containing product. The feed material is heated in the first stage in an oxidizing atmosphere to volatilize and/or thermally stabilize sulfide sulfur and evaporate moisture and heated in a reducing atmosphere in the second stage to reduce ferric iron to ferrous iron. The reduced material is then introduced into a system in which the iron oxides are substantially converted to iron carbide.Type: GrantFiled: August 28, 1996Date of Patent: September 22, 1998Assignee: Iron Carbide Holdings, Ltd.Inventor: Frank M. Stephens, Jr.
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Patent number: 5804156Abstract: A process for producing iron carbide in a fluid bed reactor in which the pressure is maintained in excess of the pressure at which the mole fraction of hydrogen in the process gas begins to decrease. The hydrogen concentration may also be increased above the equilibrium concentration for hydrogen at the temperature and pressure in the reactor. Further improvements are gained by preheating a iron ore reactor feed in which the iron oxide is primarily in the form of hematite under a reducing atmosphere, and using at least two fluid bed reactors in series.Type: GrantFiled: July 19, 1996Date of Patent: September 8, 1998Assignee: Iron Carbide Holdings, Ltd.Inventors: Gordon H. Geiger, Arden W. Swanson, Frank A. Stephens, Frank M. Stephens, Jr.
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Patent number: 5733357Abstract: A process for converting iron oxide to iron carbide using hydrogen as a reducing gas. Water is generated by the reduction of the iron oxides using hydrogen. The amount of water present in the reactor system is controlled and the water is contacted with methane in order to internally generate carbon monoxide and/or carbon dioxide gas. The carbon monoxide and/or carbon dioxide is subsequently employed to carburize the iron to iron carbide.Type: GrantFiled: February 5, 1996Date of Patent: March 31, 1998Assignee: Iron Carbide Holdings, Ltd.Inventors: Frank M. Stephens, Jr., Frank A. Stephens, Robert F. Hogsett
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Patent number: 5690717Abstract: A process for producing iron carbide in a fluid bed reactor in which the pressure may be maintained in excess of the pressure at which the mole fraction of hydrogen in the process gas begins to decrease. The hydrogen concentration is increased above the equilibrium concentration for hydrogen at the temperature and pressure in the reactor. Further improvements are gained by preheating a iron ore reactor feed in which the iron oxide is primarily in the form of hematite under a reducing atmosphere, and using at least two fluid bed reactors in series.Type: GrantFiled: March 29, 1995Date of Patent: November 25, 1997Assignee: Iron Carbide Holdings, Ltd.Inventors: James E. Stevens, Arden W. Swanson
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Patent number: 5366897Abstract: A process for controlling the conversion of reactor feed to iron carbide is disclosed. The reactor feed is subjected to a process gas in a fluidized bed reactor (10), and the off-gas from this reaction is analyzed (56) to determine its composition and the temperature (64) and pressure (66). A stability phase diagram is generated based on the temperature. Different regions of the stability phase diagram are representative of different products being formed by the conversion of the reactor feed. Based on relative concentrations of the individual gases in the off-gas and the total pressure, a point is plotted on the stability phase diagram indicative of the favored reaction product. The process parameters can then be adjusted to insure that iron carbide can be produced from the reactor feed based on the stability phase diagram. In one embodiment, the rate of conversion of the reactor feed into iron carbide is controlled.Type: GrantFiled: January 27, 1993Date of Patent: November 22, 1994Assignee: Iron Carbide Holdings, Ltd.Inventors: John P. Hager, Frank A. Stephens, Frank M. Stephens, Jr.