Abstract: A process is provided for hydrometallurgical processing of steel plant dusts containing cadmium, lead, zinc, and iron values, along with impurities such as chloride and fluoride salts of sodium, potassium, magnesium, etc. The first step in the process involves leaching the dust in a mixed sulfate-chloride medium that dissolves most of the zinc and cadmium. Any iron and aluminum dissolved in this step is precipitated by oxidation and neutralization. Zinc is recovered from the resulting solution by solvent extraction which provides a raffinate which is recycled to the leaching step with a bleed stream also provided for recovery of cadmium and removal of other impurities from the circuit. The lead sulfate residue from the leaching step is leached with caustic soda, and zinc dust is used to cement the lead out from the caustic solution, which then joins the main solution for zinc recovery.

Abstract: A process is disclosed for recovering cobalt from an alloy containing other metals as chromium, tungsten, etc. The process involves first adding the alloy to fused sodium hydroxide at a temperature of from about 750.degree. C. to about 1000.degree. C. to form a reaction mixture, the amount of sodium hydroxide being sufficient to subsequently form sodium salts which are essentially those of chromium and tungsten and hydroxides which are essentially those of cobalt and nickel. The reaction mixture is then heated at a sufficient temperature for a sufficient time while introducing an oxidizing gas into the reaction mixture to form a melt which consists essentially of the sodium salts and the hydroxides, followed by cooling the melt. The cooled melt is then contacted with sufficient water to form a solution containing the major portion of the sodium salts and a solid containing the major portion of the hydroxides, followed by separating the solid from the solution.

Abstract: A process is disclosed for recovering tungsten and rhenium from a tungsten and rhenium source. The process involves firing the source in an oxidizing atmosphere at a sufficient temperature for a sufficient time to convert the tungsten and rhenium to their respective oxides, to remove a portion of the rhenium as volatilized oxide, and to form a first fired material containing essentially all of the tungsten and the remaining portion of the rhenium, increasing the surface area of the resulting oxidized tungsten, and firing the first fired material in an oxidizing atmosphere at a sufficient temperature for a sufficient time to remove essentially all of the remaining portion of the rhenium as volatilized oxidized rhenium and to form an essentially rhenium-free oxidized tungsten.

Abstract: The precipitation product of sodium tungstate dihydrate from a melt of sodium acetate-trihydrate is a nucleating agent for latent heat storage medium on the basis of sodium acetate-trihydrate, which produces a sure and from the first storage cycle on defect-free nucleation of the sodium acetate-trihydrate at the melting point or only a few degrees below the melting point.

Abstract: The process of regenerating a stable organic soluble molybdenum-containing catalyst suitable for epoxidation of olefins with a hydroperoxide which comprises thermally precipitating and separating a molybdenum-containing solid obtained from a spent catalyst stream derived from a molybdenum catalyzed epoxidation of an olefin and solubilizing the precipitated solid by contacting with a liquid composition comprising a peroxy compound, a monohydroxy alcohol, optionally a polyhydroxy alcohol, and an organic dicarboxylic acid present in an amount of at least about 0.2 parts, by weight, of molybdenum contained in said solid.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

Abstract: A process for obtaining molybdenum as a useful product from aqueous solutions to be purified, according to claim 1 of French patent No.

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.

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.

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.

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.

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.

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.