Group Vib Metal (cr, Mo, Or W) Patents (Class 423/53)
  • Patent number: 4585628
    Abstract: Spent catalysts are extracted for removal of catalytic metals from inert supports by oxidizing subvalent metals in a solution of a ligand which forms a soluble stable complex with the oxidized metal. The ligands are salts of 1,1-dithiolate, dithiocarbimate and dithiocarbamate dianions for extraction in water and of dithiocarbamate monoions for extraction in organic solvents.
    Type: Grant
    Filed: December 10, 1984
    Date of Patent: April 29, 1986
    Assignee: American Cyanamid Company
    Inventors: Robert G. Fischer, Jr., Cynthia A. Van Savage
  • Patent number: 4578251
    Abstract: A process is disclosed for removing chromium from cobalt. The process involves first contacting an acidic cobalt chloride solution with an oxidizing agent, followed by adjusting the pH to from about 3.2 to about 5.5 with a base at a sufficient temperature to form a first solid containing essentially all of the chromium and a portion of the cobalt and a first liquor containing the balance of the cobalt, and then separating the first solid from the first liquor. The first solid is then heated at a sufficient temperature to remove essentially all of the water and form a second solid which is contacted with sufficient water and ammonium hydroxide to form a slurry which is at a pH of greater than about 3.8.
    Type: Grant
    Filed: April 1, 1985
    Date of Patent: March 25, 1986
    Assignee: GTE Products Corporation
    Inventors: Joseph E. Ritsko, Howard L. Acla
  • Patent number: 4560539
    Abstract: A process is disclosed for removing ammonia from a sodium tungstate solution. The process involves heating the solution at from about 80.degree. C. to about 95.degree. C., while at the same time maintaining the pH above about 9.4 by addition of sodium hydroxide to the sodium tungstate solution. The heating is carried out for a period of time sufficient to allow the essentially complete removal of the ammonia.
    Type: Grant
    Filed: January 11, 1985
    Date of Patent: December 24, 1985
    Assignee: GTE Products Corporation
    Inventors: Tai K. Kim, Robin W. Munn, Carl W. Boyer, Martin C. Vogt
  • Patent number: 4555387
    Abstract: A process and system are provided for flash-roasting molybdenum sulfide containing slag-forming constituents. The process comprises feeding a pneumatically suspended stream of particulate molybdenum sulfide and a mixture of fuel and oxidizing gases through a nozzle into a confined furnace chamber, the fuel gas-oxidizing gas mixture exiting from the nozzle being ignited to provide a flame thereof, the flame being maintained at a condition to provide a temperature in the furnace chamber sufficient to oxidize the molybdenum sulfide and form a volatile gas comprising molybdenum trioxide. The temperature is at least sufficient to melt the slag-forming constituents such that the slag formed is sufficiently liquid to separate from the gaseous mixture and collect at a selected portion of said chamber for removal therefrom.
    Type: Grant
    Filed: February 27, 1984
    Date of Patent: November 26, 1985
    Assignee: Amax Inc.
    Inventors: Bruce J. Sabacky, Malcolm T. Hepworth
  • Patent number: 4554138
    Abstract: A process for enhancing recovery of metals, especially cobalt, from spent hydroprocessing catalysts when the spent catalyst particles are first roasted at between 400.degree. C. and 600.degree. C. and then contacted with a first aqueous solution of ammonia and an ammonium salt to recover nickel, cobalt, molybdenum, tungsten, and vanadium. The once-leached spent hydroprocessing catalysts are again leached by contacting them with a second aqueous solution of ammonium sulfate at a pH of 1 to 4.
    Type: Grant
    Filed: October 30, 1984
    Date of Patent: November 19, 1985
    Assignee: Chevron Research Company
    Inventor: Paul J. Marcantonio
  • Patent number: 4552749
    Abstract: A process is provided for converting MoS.sub.2 to MoO.sub.2 wherein, MoS.sub.2 in particulate form is fed into a reactor while flowing MoO.sub.3 vapor therein to effect reaction thereof with MoS.sub.2 to form MoO.sub.2. The temperature in the reactor is maintained at a level sufficient to cause the reaction to go forward. A portion of the MoO.sub.2 is removed from the reactor as a product and the remainder is selectively oxidized at a temperature sufficient to generate gaseous MoO.sub.3 which is recycled to the reactor relative to the flow of MoS.sub.2 therein to convert the MoS.sub.2 to MoO.sub.2.
    Type: Grant
    Filed: January 11, 1985
    Date of Patent: November 12, 1985
    Assignee: AMAX Inc.
    Inventors: Lawrence F. McHugh, Dale K. Huggins, Malcolm T. Hepworth, John M. Laferty
  • Patent number: 4551313
    Abstract: A process and system are provided for flash-sublimation of molybdic oxide containing slag-forming constituents. The process comprises feeding a pneumatically suspended stream of particulate molybdic oxide and a mixture of fuel and oxidizing gases through a nozzle into a confined furnace chamber, the fuel gas-oxidizing gas mixture exiting from the nozzle being ignited to provide a flame thereof, the flame being maintained at a condition to provide a temperature in the furnace chamber in excess of that required to sublime molybdic oxide. The temperature is preferably at least sufficient to melt slag-forming constituents contained in said molybdic oxide such that the slag formed is sufficiently liquid to separate from the gaseous mixture and collect at a selected portion of the chamber for removal therefrom.
    Type: Grant
    Filed: February 27, 1984
    Date of Patent: November 5, 1985
    Assignee: Amax Inc.
    Inventors: Bruce J. Sabacky, Malcolm T. Hepworth
  • Patent number: 4551312
    Abstract: A process for converting molybdenite to molybdenum oxide by a flash roasting process wherein the molybdenum calcine produced in the flash roasting process is subsequently treated with a free chlorine-containing aqueous solution.
    Type: Grant
    Filed: November 13, 1984
    Date of Patent: November 5, 1985
    Assignee: Atlantic Richfield Company
    Inventor: William A. Yuill
  • Patent number: 4548700
    Abstract: A slurry hydroconversion process is provided in which a carbonaceous chargestock such as a hydrocarbonaceous oil or coal comprising a catalyst containing vanadium or molybdenum or mixtures thereof, is converted to a hydroconverted oil product. A heavy oil portion comprising metal-containing solids is separated from the oil product and partially gasified to produce a carbon-free metal-containing ash which is extracted with oxalic acid. The resulting metal-containing oxalic acid extract is recycled to the hydroconversion zone as catalyst precursor.
    Type: Grant
    Filed: December 14, 1983
    Date of Patent: October 22, 1985
    Assignee: Exxon Research and Engineering Co.
    Inventors: Roby Bearden, Jr., Clyde L. Aldridge
  • Patent number: 4547345
    Abstract: Molybdenum is recovered from an organic material, such as a spent epoxidation catalyst, by heating the material in a stream of non-oxidizing gas at a temperature of at least about 400.degree. C. to evolve the organic in the gas stream from which it is recovered and to leave a powdery residue containing essentially all of the molybdenum.
    Type: Grant
    Filed: March 14, 1984
    Date of Patent: October 15, 1985
    Assignee: AMAX Inc.
    Inventors: Roger F. Sebenik, Jerry D. Baker, John M. Laferty
  • Patent number: 4533527
    Abstract: Tungsten can be extracted into solution from tungsten carbide powder residues with aqueous hydrogen peroxide to a greater extent by employing in solution a catalytic quantity of hydrochloric acid, such as a mole ratio to the tungsten preferably in the range of at least 0.1:1 moles of HCl per mole tungsten, and often up to about 2.5 moles of HCl per mole of tungsten at 55.degree. to 85.degree. C. The selection of the mole ratio in practice usually takes into account the grade of tungsten carbide starting material. It is very preferable to use at least 7 moles hydrogen peroxide per mole of tungsten and an extraction temperature of 65.degree. to 75.degree. C.
    Type: Grant
    Filed: August 17, 1983
    Date of Patent: August 6, 1985
    Assignee: Interox Chemicals Limited
    Inventors: George Farrell, Diana M. Anderson, Michael E. Walton
  • Patent number: 4530763
    Abstract: A method for treating waste fluids to remove selected chemicals such as minerals and metals wherein a bacterial culture that will attach to a selected chemical is transferred to a nutrient medium for a time period sufficient to produce satisfactory bacterial cell growth. The bacterial cells are then attached to a porous fiber webbing supported in a suitable container and the nutrient medium is then withdrawn from the container and waste fluid introduced into the container for a period of time sufficient to attach the chemical to the bacterial cells. The waste fluid is then removed from the container and the chemical separated from the fiber webbing.
    Type: Grant
    Filed: July 11, 1983
    Date of Patent: July 23, 1985
    Inventors: Robert A. Clyde, Andrew Whipple
  • Patent number: 4523948
    Abstract: A method is provided for treating molybdenum concentrates in a roasting furnace having a first roasting zone and at least a second roasting zone, the concentrate containing residual flotation oil in an amount over 2% by weight which during roasting inhibits the roasting capacity of the furnace. The improvement resides in deoiling the molybdenite concentrate, feeding the deoiled concentrate to the first roasting zone, and applying heat to the concentrate in the first roasting zone, including the sensible heat of the concentrate and heat generated by extraneous fuel, sufficient to heat the concentrate to a roasting temperature sufficiently high to initiate a substantially self-sustaining roasting reaction but not exceeding about 1250.degree. F. The amount of heat generated by combustion of the extraneous fuel is not substantially in excess of that required to heat the concentrate to the temperature at which self-sustaining roasting reactions are initiated in the first roasting zone.
    Type: Grant
    Filed: February 14, 1984
    Date of Patent: June 18, 1985
    Assignee: Amax Inc.
    Inventors: Larry F. McHugh, Daniel E. Barchers
  • Patent number: 4521381
    Abstract: In a process is disclosed for recovering rhenium from tungsten and rhenium bearing material by oxidizing and fusing the starting material, solubilizing the tungsten and rhenium values, passing the resulting solution through a strongly basic anion exchange resin to retain the rhenium, removing the rhenium from the resin with an organic stripping liquid of tributylphosphate and hydrochloric acid, washing the remaining rhenium off the resin with water, combining the water and organic to form a two phase system in which the organic phase contains the major portion of the rhenium, and contacting with aqueous ammonia to strip values.
    Type: Grant
    Filed: November 7, 1984
    Date of Patent: June 4, 1985
    Assignee: GTE Products Corporation
    Inventors: Alan D. Douglas, Kenneth T. Reilly
  • Patent number: 4512958
    Abstract: A method of recovering molybdenum oxide as in U.S. Pat. No. 4,379,127 wherein, however, the temperature in the autoclave and the pressure therein are controlled within narrow ranges by increasing the suspension density of the molybdenum sulfide suspension fed to the autoclave upon a fall in temperature and by adding water to the slurry of molybdenum sulfide concentrate formed before introduction into the autoclave upon an increase in temperature.
    Type: Grant
    Filed: October 28, 1983
    Date of Patent: April 23, 1985
    Assignee: GfE Gesellschaft fur Elektrometallurgie mbH
    Inventors: Gunter Bauer, Joachim Eckert
  • Patent number: 4504448
    Abstract: Foaming in the hydrometallurgical treatment of a tungsten-containing aqueous solution due to the presence of carbonaceous organic material impurities, such as flotation reagents, is substantially inhibited by the addition of effective amounts of powdered activated carbon, the carbon with the adsorbed impurities being thereafter separated from the solution by filtering. The activated carbon also protects the solvent extraction circuit from contamination. The method is particularly applicable to slurries of tungsten oxide concentrates during the high temperature, high pressure leaching thereof with sodium carbonate solutions in an autoclave.
    Type: Grant
    Filed: February 27, 1984
    Date of Patent: March 12, 1985
    Assignee: Amax Inc.
    Inventors: Dennis E. Voelker, Leo W. Beckstead, Robert F. Hogsett
  • Patent number: 4500495
    Abstract: A process for recovering the metal values from spent hydroprocessing catalyst particles. The metal values will include at least one metal of Group VIII of the Periodic Table and at least one metal of Group Vb or Group VIb of the Periodic Table. The spent catalyst particles are first roasted at between 400.degree. C. and 600.degree. C. and then contacted with a first aqueous solution of ammonia and an ammonium salt forming a first pregnant liquor. The once-leached spent hydroprocessing catalysts are contacted with a second aqueous solution of sulfur dioxide forming a second pregnant liquor. The metal values are precipitated from the second pregnant liquor with hydrogen sulfide and the precipitate is roasted with unroasted spent hydroprocessing catalysts. The metal values of Group Vb and Group VIb in the first pregnant liquor are transferred into a first organic solution by liquid ion exchange.
    Type: Grant
    Filed: August 1, 1983
    Date of Patent: February 19, 1985
    Assignee: Chevron Research Company
    Inventors: Gale L. Hubred, Dean A. Van Leirsburg
  • Patent number: 4489044
    Abstract: Tungsten monocarbide is prepared by sparging a molten composition comprising an alkali metal halide and an oxygen compound of tungsten with a gas comprising a gaseous hydrocarbon, particularly methane.
    Type: Grant
    Filed: January 27, 1984
    Date of Patent: December 18, 1984
    Assignee: The United States of America as represented by the Secretary of the Interior
    Inventors: John M. Gomes, Andrea E. Raddatz, Elizabeth G. Baglin
  • Patent number: 4485074
    Abstract: Process for the recovery of molybdenum from an organic solution, such as a spent catalyst solution obtained from the molybdenum catalyzed epoxidation of an olefinically unsaturated organic compound with an organic hydroperoxide as oxidizing agent and removal from the crude epoxidation mixture of product epoxide and the alcohol corresponding to the hydroperoxide, said process comprising:(a) admixing the organic solution with water in an amount between about 0.5 and 10 percent, based on the weight of the organic solution;(b) heating the resultant admixture to a temperature in the range of between about 150.degree. C. and 250.degree. C. under pressure sufficient to maintain the admixture in the liquid phase and for a time sufficient to precipitate at least a portion of the molybdenum contained in the organic solution as a solid; and (c) separating the precipitated molybdenum containing solid from the organic solution.
    Type: Grant
    Filed: January 21, 1981
    Date of Patent: November 27, 1984
    Assignee: Atlantic Richfield Company
    Inventor: Richard B. Poenisch
  • Patent number: 4483829
    Abstract: Waste products from the chrome-tanning of hides are washed and then chopped in water, with subsequent hydrolyzation at a pH of at least 10.5 and at boiling or near-boiling temperature. The resulting suspension is filtered to yield a polypeptide solution and a cake of solids consisting essentially of chromium hydroxide. The solution is neutralized, dehydrated, cooled and filtered to provide a virtually chromium-free proteinaceous substance usable as plant or animal feed; the solids are washed, filtered and acidified to provide chromium sulfate suitable for reutilization in tanning.
    Type: Grant
    Filed: January 27, 1983
    Date of Patent: November 20, 1984
    Inventor: Giuliano Guardini
  • Patent number: 4482526
    Abstract: Tungsten and molybdenum are recovered from sulfur bearing material such as sulfide sludges by a pollution free process in which the sulfur bearing material is heated with agitation in an aqueous solution of sodium carbonate to form water soluble molybdenum and tungsten compounds without forming any appreciable amount of water soluble sulfur compounds. The reaction mixture is oxidized to convert partially reduced tungsten values or molybdenum values to sodium tungstate and sodium molybdate respectively. The liquid phase containing tungsten and molybdenum is separated from the solid phase containing free sulfur.
    Type: Grant
    Filed: December 1, 1983
    Date of Patent: November 13, 1984
    Assignee: GTE Products Corporation
    Inventors: Joseph E. Ritsko, Howard L. Acla
  • Patent number: 4477315
    Abstract: An aqueous acidic trivalent chromium electrolyte and process for electrodepositing chromium platings comprising an electrolyte containing trivalent chromium ions, a complexing agent, halide ions, ammonium ions and a reducing agent comprising an ion selected from the group consisting of scandium, yttrium, lanthanum, titanium, zirconium, hafnium, molybdenum, arsenic, selenium, tellurium, cerium, uranium, and tin present in an amount effective to maintain the concentration of hexavalent chromium ions formed in the bath at a level at which satisfactory chromium electrodeposits are obtained.
    Type: Grant
    Filed: May 12, 1983
    Date of Patent: October 16, 1984
    Assignee: OMI International Corporation
    Inventor: Thaddeus W. Tomaszewski
  • Patent number: 4477318
    Abstract: An aqueous acidic trivalent chromium electrolyte and process for electrodepositing chromium platings comprising an electrolyte containing trivalent chromium ions, a complexing agent, halide ions, ammonium ions and a reducing agent comprising a metal ion selected from the group consisting of Gold, Silver, Platinum, Palladium, Rhodium, Iridium, Osmium, Ruthenium, Rhenium, Gallium, Germanium, Indium, Samarium, Europium, Gadolinium, Terbium, Dysprosium, Holmium, Erbium, Thulium, Ytterbium, Lutetium, and Praseodymium present in an amount effective to maintain the concentration of hexavalent chromium ions formed in the bath at a level at which satisfactory chromium electrodeposits are obtained.
    Type: Grant
    Filed: May 12, 1983
    Date of Patent: October 16, 1984
    Assignee: OMI International Corporation
    Inventor: Thaddeus W. Tomaszewski
  • Patent number: 4474735
    Abstract: A process for the recovery of valuable metals from roasted crude-oil sulfur-extraction catalyst waste is disclosed. In this process the value metals can be separated from aluminum in a single stage by treating the waste at elevated temperature and pressure with such an amount of sulfate solution that the waste dissolves and the aluminum simultaneously precipitates as alunite, which is separated from the solution which contains the other value metals. A sulfate solution is preferably added in such an amount that the concentration of sulfuric acid in the solution is 2-30 g/l at the end of the stage.
    Type: Grant
    Filed: September 28, 1982
    Date of Patent: October 2, 1984
    Assignee: Outokumpu Oy
    Inventors: Jussi K. Rastas, Kauko J. Karpale, Heikki Tiitinen
  • Patent number: 4470956
    Abstract: Metal carbide is reclaimed from scrap by sorting the scrap to separate pieces of cemented carbide having similar composition and grain size and treating the separated portion to form metal carbide grains which may be resintered with metal binder to obtain cemented carbides having grain characteristics similar to the starting material.
    Type: Grant
    Filed: October 18, 1982
    Date of Patent: September 11, 1984
    Assignee: GTE Products Corporation
    Inventors: Richard F. Cheney, Anil Bansal
  • Patent number: 4466945
    Abstract: Metal carbide is reclaimed from scrap by sorting the scrap to separate pieces of cemented carbide having similar composition and grain size and treating the separated portion to form metal carbide grains which may be resintered with metal binder to obtain cemented carbides having grain characteristics similar to the starting material.
    Type: Grant
    Filed: August 8, 1983
    Date of Patent: August 21, 1984
    Assignee: GTE Products Corporation
    Inventors: Richard F. Cheney, Anil Bansal
  • Patent number: 4462822
    Abstract: A process is disclosed for roasting molybdenite concentrates directly to molybdenum dioxide. The process comprises establishing a roasting zone having a temperature of about 700.degree. C. to about 800.degree. C., introducing into the roasting zone particulate molybdenum dioxide and molybdenite in a weight ratio of at least about 2:1 along with an oxygen-containing gas in amount sufficient to oxidize the sulfur content of the molybdenite to molybdenum dioxide.
    Type: Grant
    Filed: November 8, 1983
    Date of Patent: July 31, 1984
    Assignee: Amax Inc.
    Inventors: Bruce J. Sabacky, Malcolm T. Hepworth
  • Patent number: 4457776
    Abstract: A process for the removal of arsenic compounds from tungsten and/or molybdenum concentrates by selective extraction, characterized in that the concentrates are extracted with an aqueous solution of a ferric compound of a pH below 2.5 and a temperature of at least 60.degree. C.
    Type: Grant
    Filed: August 2, 1983
    Date of Patent: July 3, 1984
    Assignee: Shell Internationale Research Maatschappij B.V.
    Inventors: Jan P. Van't Sant, Arjen Nieuwhof
  • Patent number: 4455283
    Abstract: A process for recovering molybdenum values from a spent catalyst solution obtained from a crude reaction product of a molybdenum catalyzed epoxidation of an olefin with an organic hydroperoxide from which crude reaction product epoxide and alcohol corresponding to the hydroperoxide is removed, which process comprises vacuum evaporation without suppressed vaporization of the spent catalyst solution feed.
    Type: Grant
    Filed: May 24, 1982
    Date of Patent: June 19, 1984
    Assignee: Atlantic Richfield Company
    Inventor: Norman H. Sweed
  • Patent number: 4454098
    Abstract: A process is disclosed wherein tungsten is recovered from hazardous waste material containing said tungsten, arsenic, and other impurities which can consist of magnesium, phosphorus, and silicon and the resulting waste is treated to render it nonhazardous according to EPA standards for arsenic. Said process involves digesting said hazardous waste material in an aqueous solution of an alkali metal hydroxide, adjusting the pH of the resulting solution to about 11.0 to about 13.0 with NaOH to precipitate essentially all of the magnesium and silicon species, filtering the digestion mix to remove the solids from said resulting solution which contains about 80 to about 100% of said tungsten and essentially none of said magnesium and said silicon, slurrying the hazardous solids in hot water, and adding to the slurry a ferric salt solution to precipitate ferric hydroxide, filtering this mixture to give a solid which passes the EPA standard test for solids with respect to arsenic.
    Type: Grant
    Filed: December 1, 1983
    Date of Patent: June 12, 1984
    Assignee: GTE Products Corporation
    Inventors: Richard A. Scheithauer, Clarence D. Vanderpool, Michael J. Miller, Martin B. MacInnis
  • Patent number: 4450144
    Abstract: A process for stripping tungsten values from a tungsten-bearing acidic liquid organic phase into a basic aqueous ammoniacal stripping solution comprises mixing the organic phase and the stripping solution with a high-shear mixing device to maximize the pH gradient between the organic phase and the aqueous solution whereby growth of any precipitated ammonium paratungstate crystals is minimized and the dissolution thereof is maximized and to strip the tungsten values from the organic phase into the stripping solution.
    Type: Grant
    Filed: July 21, 1982
    Date of Patent: May 22, 1984
    Assignee: Amax Inc.
    Inventors: John M. Laferty, Paul B. Queneau, Leo W. Beckstead
  • Patent number: 4448755
    Abstract: In a process for producing pure ammonium paratungstate from ammonium tungstate solutions containing tin, sulfide is added to the ammonium tungstate solution in an amount sufficient to form a soluble complex of the sulfide with the tin. The solution is then evaporated to a volume at which essentially all of the tungsten is in the form of insoluble ammonium paratungstate and essentially all of the tin is in the mother liquor in the form of a soluble complex along with other impurities. The solid ammonium paratungstate is then separated from the mother liquor by filtration.
    Type: Grant
    Filed: December 1, 1983
    Date of Patent: May 15, 1984
    Assignee: GTE Products Corporation
    Inventors: Richard A. Scheithauer, Michael J. Miller, Martin B. MacInnis, James N. Christini, Martin C. Vogt
  • Patent number: 4444733
    Abstract: A hydrometallurgical process is provided for the recovery of molybdenum values from a molybdenum disulfide concentrate containing copper. The process comprises forming an aqueous slurry of finely divided molybdenum concentrate of carbonates and hydroxides of alkali metals, and pressure leaching the slurry in the presence of oxygen at an elevated temperature and pressure for a time sufficient to effect conversion of the contained molybdenum values to alkali metal molybdate and provide a residue containing copper oxide or basic copper carbonate from which copper is later recovered. The molybdenum values are recovered from solution by solvent extraction and the solvent thereafter stripped of the molybdenum as ammonium molybdenum using ammonium hydroxide. The molybdenum is recovered as crystals of ammonium molybdate by crystallization, e.g., by evaporating the stripping solution.
    Type: Grant
    Filed: February 28, 1983
    Date of Patent: April 24, 1984
    Assignee: Amax Inc.
    Inventors: John M. Laferty, Dale K. Huggins, John D. Bruno
  • Patent number: 4441993
    Abstract: A process for recovering metallic values by putting the values into solution and separating undesired mineral matter from the solution using countercurrent flotation is provided. The process involves leaching metallic values from host rock, conditioning the resultant ore pulp with the required reagents to achieve selective flotation of mineral matter in the metallic values solution, introducing the conditioned ore pulp into flotation cells, along with counterflow of solution from an immediately subsequent flotation step, wherein simultaneous washing and flotation is achieved, and the mineral matter is removed leaving a solution of the metallic values. The resultant mineral matter froth product is subjected to subsequent stages of flotation and simultaneous washing with counterflow of solution removed from each subsequent stage of flotation, water and/or barren solution being used for washing in the final flotation stage.
    Type: Grant
    Filed: May 3, 1979
    Date of Patent: April 10, 1984
    Assignee: Fluor Corporation
    Inventor: Frank P. Howald
  • Patent number: 4440729
    Abstract: The invention is directed to a process and apparatus for dissolving a molybdenum core wire in a tungsten filament coil which comprises reacting the filament coil in a sealed reaction vessel fitted with at least one liquid trap with an acid mixture containing nitric acid, sulfuric acid and water in the presence of an oxygen containing gas wherein the amount of the oxygen containing gas is controlled by a liquid level sensing device attached to the liquid trap. The invention enables efficient conversion of nitrogen oxide gases to nitric acid and recovery of molybdenum from the reaction vessel.
    Type: Grant
    Filed: April 14, 1981
    Date of Patent: April 3, 1984
    Assignee: Lumalampan Aktiebolag
    Inventor: Gunther Jonsson
  • Patent number: 4439285
    Abstract: An aqueous acidic trivalent chromium electrolyte and process for electrodepositing chromium platings comprising an electrolyte containing trivalent chromium ions, a complexing agent, halide ions, ammonium ions and a reducing agent comprising neodymium ions present in an amount effective to maintain the concentration of hexavalent chromium ions formed in the bath at a level at which satisfactory chromium electrodeposits are obtained.
    Type: Grant
    Filed: May 12, 1983
    Date of Patent: March 27, 1984
    Assignee: OMI International Corporation
    Inventor: Thaddeus W. Tomaszewski
  • Patent number: 4437884
    Abstract: Metal sulfide ores which contain organic matter are oxidized by roasting in a multiple hearth furnace, wherein at least a portion of gases formed during the oxidation is recycled from a higher-temperature, upper portion of the furnace to a lower-temperature, lower portion of the furnace. The control of air pollution from the furnace is facilitated by making some volatile organics, otherwise vented from the furnace, available for combustion, and by increasing the sulfur oxide concentration in the furnace gases.
    Type: Grant
    Filed: August 30, 1982
    Date of Patent: March 20, 1984
    Assignee: Union Oil Company of California
    Inventors: Raymond Hawryluk, Clyde R. Johnson, N. Henri Masarky
  • Patent number: 4432950
    Abstract: In a process for recovering refractory metal values from a refractory metal carbide cemented with a metal binder. The coated cemented carbide is treated with sulfuric acid to deteriorate the coating.
    Type: Grant
    Filed: September 16, 1982
    Date of Patent: February 21, 1984
    Assignee: GTE Products Corporation
    Inventors: Clarence D. Vanderpool, Richard A. Scheithauer, Richard G. Warmington
  • Patent number: 4432947
    Abstract: A process for obtaining molybdenum as a useful product from aqueous solutions to be purified, according to claim 1 of French patent No.
    Type: Grant
    Filed: July 16, 1982
    Date of Patent: February 21, 1984
    Assignee: Uranium Pechiney Ugine Kuhlmann
    Inventor: Pierre Maurel
  • Patent number: 4432953
    Abstract: A process for enhancing recovery of cobalt from spent hydroprocessing catalysts when the spent catalyst particles are first roasted at between 400.degree. C. and 600.degree. C. and then contacted with a first aqueous solution of ammonia and an ammonium salt to recover nickel, cobalt, molybdenum and vanadium. The once-leached spent hydroprocessing catalysts are contacted with a second aqueous solution of sulfur dioxide. The metal values are precipitated with hydrogen sulfide and the precipitate is roasted with unroasted spent hydroprocessing catalysts.
    Type: Grant
    Filed: September 24, 1982
    Date of Patent: February 21, 1984
    Assignee: Chevron Research Company
    Inventors: Gale L. Hubred, Dean A. Van Leirsburg
  • Patent number: 4431625
    Abstract: Chromium trioxide is made by reacting sodium dichromate with sulphuric acid in an aqueous reaction mixture, evaporating the resultant liquor to cause crystallization of most of the chromium trioxide and to cause the concentration of sodium sulphates to be close to but below that at which sulphate crystals start to form, and separating the chromium trioxide crystals from the evaporated liquor. The liquor may then be cooled so as to cause crystallization of sodium sulphates, generally as sodium bisulphate, and the resultant liquor, after separation of the crystals, may be recycled to the reaction mixture containing dichromate and sulphuric acid.
    Type: Grant
    Filed: June 28, 1983
    Date of Patent: February 14, 1984
    Assignee: British Chrome & Chemicals Limited
    Inventors: Michael A. Marshall, Danvers A. Swales
  • Patent number: 4420331
    Abstract: A process for the removal of arsenic compounds from tungsten and/or molybdenum concentrates by selective extraction, characterized in that the concentrates are extracted with an aqueous solution of a ferric compound at a pH below 2.5 and a temperature of at least 60.degree. C.
    Type: Grant
    Filed: January 21, 1982
    Date of Patent: December 13, 1983
    Assignee: Shell Internationale Research Maatschappij B.V.
    Inventors: Jan P. van't Sant, Arjen Nieuwhof
  • Patent number: 4410443
    Abstract: A method of preparing a solution of the nitrate of iron and mixed chromium from a spent iron oxide-chrome oxide shift catalyst which comprises dissolving said spend iron oxide-chrome oxide shift catalyst with nitric acid in the presence of from 5-25% by weight of the catalyst of an additive selected from the group consisting of ferrous sulfate and sodium thiosulfate.
    Type: Grant
    Filed: May 24, 1982
    Date of Patent: October 18, 1983
    Assignee: Katalco Corporation
    Inventor: George N. Pessimisis
  • Patent number: 4406866
    Abstract: In a process for recovering refractory metal values from a coated refractory metal carbide cemented with a metal binder, the coated cemented carbide is treated with hydrochloric acid to deteriorate the coating.
    Type: Grant
    Filed: September 20, 1982
    Date of Patent: September 27, 1983
    Assignee: GTE Products Corporation
    Inventor: Kenneth T. Reilly
  • Patent number: 4405571
    Abstract: A process for the selective dissolution of molybdenum in the presence of tungsten in which the molybdenum is dissolved in an aqueous solution, having a pH of from -0.5 to +2.0, of a peroxy compound selected from the group consisting of hydrogen peroxide and ammonium peroxysulfate and in the presence of a catalyst selected from a salt of the group consisting of iron, nickel, copper, silver and thallium.
    Type: Grant
    Filed: January 7, 1982
    Date of Patent: September 20, 1983
    Assignee: MTA Muszaki Fizikai Kutato Intezete
    Inventors: Karoly Vadasdi, Laszlo Bartha, Tivadar Millner, Endre Tekula, Andras Kiss
  • Patent number: 4393029
    Abstract: An iron-free chromium(III) compound is precipitated at an elevated temperature and pressure from an acidic aqueous solution which contains iron and chromium. In order to prevent coprecipitation of iron, an additive is added to the precipitation stage in an amount sufficient to provide in the precipitation conditions at least 2 g/l of bivalent chromium in the solution.
    Type: Grant
    Filed: July 22, 1981
    Date of Patent: July 12, 1983
    Assignee: Outokumpu Oy
    Inventors: Seppo O. Heimala, Stig E. Hultholm, Frans H. Tuovinen
  • Patent number: 4382068
    Abstract: The invention provides a novel method for selectively recovering molybdenum nd vanadium values from a spent catalyst used for the hydrogenation desulfurization of petroleums by the extraction with an alkaline extractant solution without the necessity of preliminary calcination of the spent catalyst containing, in addition to the molybdenum and vanadium values, nickel, cobalt and other heavy metals as well as sulfur and carbonaceous matters as the contaminants supported by or deposited on an alumina carrier. The inventive method utilizes an aqueous alkaline solution of sodium carbonate with admixture of hydrogen peroxide as an oxidizing agent whereby an unexpectedly high percent extraction is obtained for the molybdenum and vanadium values reaching 99% or higher for the former and about 85% for the latter while the extraction of nickel, cobalt and aluminum can be minimized.
    Type: Grant
    Filed: November 17, 1981
    Date of Patent: May 3, 1983
    Assignee: Director-General of the Agency of Industrial Science and Technology
    Inventor: Naganori Rokukawa
  • Patent number: 4379127
    Abstract: A method of recovering molybdenum oxide by oxidation of a molybdenum sulfide concentrate contaminated with impurities wherein the concentrate in an average particle size in the range of 20 to 90 microns is suspended to form an aqueous suspension which is oxidized at elevated temperature and an elevated oxygen partial pressure in an autoclave. The suspension withdrawn from the autoclave is subjected to filtration to remove the molybdenum oxide from the primary filtrate containing sulfuric acid and this filtrate is neutralized with lime to form calcium sulfate which is then removed from the suspension to provide a second filtrate. According to the invention, only this second filtrate is recirculated at a rate such that the suspension density in the oxidation stage is between 100 to 150 g of solids per liter and this suspension density is maintained in the oxidation stage by the recirculation.
    Type: Grant
    Filed: October 5, 1981
    Date of Patent: April 5, 1983
    Assignee: GfE Gesellschaft fur Elektrometallurgie mbH
    Inventors: Gunter Bauer, Joachim Eckert
  • Patent number: 4376647
    Abstract: A process for removing sulfur from sulfide-bearing ores by reacting water vapor with the sulfide-bearing ore forming hydrogen sulfide while simultaneously regenerating water vapor by reacting the hydrogen sulfide with lime. Advantageously, the process occurs in the absence of a net consumption or production of gaseous species so that the process can be carried out in a closed system with respect to the gaseous species. Sulfide-bearing ores which can be treated using the process of this invention include sulfide-bearing ores of molybdenum, zinc, iron, mercury, and copper. Advantageously, the molybdenum oxide so produced from the sulfide-bearing ore of molybdenum can be reacted further with lime and water producing calcium molybdate and hydrogen. The chalcopyrite form of the sulfide-bearing ore of copper produces bornite and magnetite.
    Type: Grant
    Filed: February 17, 1981
    Date of Patent: March 15, 1983
    Assignee: University of Utah
    Inventor: Hong Y. Sohn
  • Patent number: 4374805
    Abstract: Metals such as iron, uranium, vanadium, molybdenum and rare earths are reduced to lower oxidation states in various acid media using silicon metal or an iron-silicon alloy. In particular, ferric iron and hexavalent uranium in wet-process phosphoric acid are reduced to the ferrous and tetravalent states, respectively, using silicon metal or an iron-silicon alloy to provide a feed acid which is suitable for extraction with an extractant which is selective for tetravalent uranium such as a mixture of mono- and di-(alkylphenyl) esters of orthophosphoric acid.
    Type: Grant
    Filed: May 7, 1980
    Date of Patent: February 22, 1983
    Assignee: Uranium Recovery Corporation
    Inventors: Ralph E. Worthington, Michael A. Smith, John M. Tobias