Abstract: A process for preparing finely-divided oxides of metals of metalloids of the elements of main groups III and IV and sub-groups III, IV, V and VI of the Periodic System of Elements, comprising reacting compounds of these elements with a polymerizable hydrocarbon compound or mixture to form a polymer product, which is then thermally treated to yield the oxide product.

Abstract: Metal oxides prepared by exchange reactions between organosemiconductor oxides (such as disiloxanes) and metal coordination compounds (such as neutral metal complexes, metal chelates and chlorometalates), metallic halides (such as zinc chloride), or organometallic compounds (such as methylithium) in inert environments and anhydrous solvents.

Abstract: Potassium impurity is removed from ammonium molybdate by dissolving the ammonium molybdate in hot acid, allowing the acid solution to cool whereby the ammonium molybdate precipitates out of the solution as molybdenum trioxide and then separating, washing and drying the molybdenum trioxide.

Abstract: A manufacturing method for dielectric ceramic compositions of lead-based perovskite containing lead magnesium tungstate [Pb(Mg.sub.1/2 W.sub.1/2)O.sub.3 ] as a component which is characterized in that magnesium tungstate powder [MgWO.sub.4 ] is used as a starting material instead of MgO and WO.sub.3 powder.

Abstract: A radiation-sensitive material comprising a polyacid composed of tungsten and niobium, titanium and/or tantalum. A uniform film can be formed by an easy spin coating method. The polyacid has a radiation sensitivity higher than that of a polyacid comprising only tungsten.

Abstract: A material for an optical component comprising polytungstic acid having peroxo groups, and an optical component, at least part of which is constituted of a thin film of the above-mentioned material. By using this material, a thin film of an inorganic material having an excellent stability is formed by the inexpensive wet painting method. An optical component using the above-mentioned thin film can be formed on an arbitrary substrate with high accuracy at a low temperature of about 100.degree. C. or below. The polytungstic acid may contain carbon as a heteroatom and/or may have Nb, Ti, V, Ta and/or Mo substituted for part of W.

Abstract: A method is disclosed for producing ammonium paratungstate from cemented tungsten carbide which comprises subjecting the cemented tungsten carbide to electrolysis by passing about 0.5 to about 20 volts through an ammoniacal solution selected from the group consisting of ammonium hydroxide-ammonium chloride solution, ammonium hydroxide-ammonium carbonate solution, and ammonium hydroxide-ammonium sulfate solution, wherein platinum and the cemented tungsten carbide serve as the anode and wherein the anode is immersed in the solution, to decompose the cemented tungsten carbide and form a solution of ammonium tungstate from which is crystallized ammonium paratungstate.

Abstract: A process is disclosed for purifying molybdenum containing arsenic and phosphorus which involves leaching molybdenum trioxide in an acid at a temperature of above about 70.degree. C.

Abstract: A method of separating tungsten from molybdenum wherein impure acid leached molybdenum trioxide containing tungsten is combined with ammonium hydroxide to form an ammonium molybdate solution, the solution is contacted with tin (IV) oxide hydrate to cause sorption of essentially all of the tungsten contained therein without causing sorption of molybdenum, the tin (IV) oxide hydrate with the sorped tungsten is separated from the ammonium molybdate solution, and the ammonium molybdate solution is dried and fired to obtain purified molybdenum trioxide.

Abstract: Directed to a process for producing a tungsten product of enhanced purity from ammonium paratungstate (APT) with a minimum number of processing steps which comprises mixing the APT with an ammonium solution, autoclaving the mixture at a temperature above the boiling point thereof to dissolve the APT and recrystallizing APT from the solution to yield an APT product of enhanced marketability.

Abstract: A process is disclosed for purifying molybdenum which involves adding to an acidic slurry of molybdenum trioxide, a source of magnesium ions in a solid form, with the amount of magnesium and the magnesium ion concentration in the subsequently formed ammonium molybdate solution being sufficient to subsequently form insoluble compounds containing greater than about 80% by weight of the arsenic and greater than about 80% by weight of the phosphorus, and ammonia in an amount sufficient to subsequently dissolve the molybdenum and subsequently form the insoluble compounds, digesting the resulting ammoniated slurry at a temperature sufficient to dissolve the molybdenum and form an ammonium molybdate solution while the pH is maintained at from about 9 to about 10 to form a solid containing the insoluble compounds, and separating the solid from the ammonium molybdate solution.

Abstract: Here is provided an adsorbent for adsorbing and removing an arsenic compound which becomes a catalyst poison in a selective contact reduction process for removing nitrogen oxides (NOx) from a combustion exhaust gas by the use of an ammonia as a reducing agent and a denitrating catalyst.The adsorbent of the present invention comprises a material in which the total volume of pores is 0.2 to 0.7 cc/g and the volume of the pores having a pore diameter of 300 .ANG. or more is 10% or more with respect to the total pore volume, and the material is a specific element, its oxide, an ion-exchanged zeolite or the like.In addition, the present invention is directed to a method for removing the arsenic compound from the combustion exhaust gas by injecting the adsorbent into the flow of the gas on the upstream side of the denitrating catalyst.

Abstract: A whisker of molybdenum oxide in the form of a filament, rod or flake. Molybdenum oxide whiskers are produced by firing metallic molybdenum at a temperature of at least 400.degree. C., preferably at least 800.degree. C., in an atmosphere containing oxygen, or by firing an organic molybdenum compound in an atmosphere containing oxygen at a temperature which is at least equal to its thermal decomposition temperature. They are very strong crystals which are expected to be useful as a filler for plastics and for a variety of other applications.

Abstract: Process for the manufacture of vitreous metal oxides in which a metal alcoholate derived from an alcohol, the pka of which is less than 15.74, is hydrolysed with an aqueous medium, the pH of which is greater than 1.5. The process is applied especially to the manufacture of vitreous zirconium oxide.

Abstract: Molybdenum hexacarbonyl is prepared by carbonylating diammonium oxopentachloromolybdate (V) (NH.sub.4).sub.2 (MoOCl.sub.5) at pressures up to about 2000 psig and temperatures up to about 150.degree. C. in a solvent such as tetrahydrofuran, using a metallic reductant such as magnesium and an oxygen scavenger such as aluminum trichloride.

Abstract: A novel phase of molybdenum trioxide and mixed metal oxides of molybdenum and tungsten is disclosed.

Abstract: A highly dielectric powder the chemical composition of which is represented by the following general formula:(Sr.sub.x Pb.sub.1-x TiO.sub.3).sub.y (PbMg.sub.0.5 W.sub.0.5 O.sub.3).sub.1-y(wherein 0.ltoreq.x<1 and 0<y<1) is produced by a method which comprises adding a mixture consisting of strontium alkoxide (which is not required when the subscript, x, in the aforementioned general formula is 0), lead alkoxide, titanium alkoxide, and magnesium alkoxide to an aqueous solution of ammonium para-tungstate thereby effecting hydrolysis of alkoxides and coprecipitation of a tungsten component and subsequently heating the resultant precipitate.

Abstract: A process is disclosed for producing ammonium molybdate from molybdenum trioxide which involves digesting molybdenum trioxide with ammonia in a sealed vessel equipped with one or more stirrers at a temperature of from about 20.degree. C. to about 80.degree. C., with the amount of ammonia being equal to the stoichiometric amount needed to form normal ammonium molybdate, up to about 2.9 times this stoichiometric amount, to form an ammonium molybdate solution containing essentially all of the starting molybdenum; followed by separating the solution from any insolubles. The method is especially useful for molybdenum containing iron as an impurity. Essentially all of the iron reports with the insolubles.

Abstract: Efficient, regenerable sorbents for removal of H.sub.2 S from high temperature gas streams comprise porous, high surface area particles. A first class of sorbents comprise a thin film of binary oxides that form a eutectic at the temperature of the gas stream coated onto a porous, high surface area refractory support. The binary oxides are a mixture of a Group VB or VIB metal oxide with a Group IB, IIB or VIII metal oxide such as a film of V-Zn-O, V-Cu-O, Cu-Mo-O, Zn-Mo-O or Fe-Mo-O coated on an alumina support. A second class of sorbents consist of particles of unsupported mixed oxides in the form of highly dispersed solid solutions of solid compounds characterized by small crystallite size, high porosity and relatively high surface area. The mixed oxide sorbents contain one Group IB, IIB or VIIB metal oxide such as copper, zinc or manganese and one or more oxides of Groups IIIA, VIB or VII such as aluminum, iron or molybdenum.

Abstract: A treated decomposable compound of molybdenum, which has been prepared by the catalytic dehydrogenation of a decomposable compound of molybdenum wherein the molybdenum has a valence state greater than zero or by the treating of the decomposable compound of molybdenum with a reducing agent, is mixed with a hydrocarbon-containing feed stream. The hydrocarbon-containing feed stream containing such treated decomposable compound of molybdenum is then contacted with a catalyst composition comprising a support selected from the group consisting of alumina, silica and silica alumina and a promoter comprising at least one metal selected from the group consisting of Group VIB, Group VIIB, and Group VIII of the Periodic Table to reduce the concentration of metals, sulfur, nitrogen, Ramsbottom carbon residue and/or heavies contained in the hydrocarbon-containing feed stream.

Abstract: The process of producing high surface area mixed metal oxides comprising selecting a precursor characterized by the following formula:A.sub.x M.sub.a [M'(CN).sub.c ].sub.b.nH.sub.2 Ox=0-4;a=0-4;b=0.1-4;c=4-8;n=0-30;A=alkali, alkaline earth metal, Al, Si or mixtures;M=rare earth metals, transition metals or mixture thereof; andM'=transition metal capable of forming a cyanide (e.g. Group VIA-VIII A) or mixture thereof,and heating the precursor at a temperature rate of below 1.degree.C/minute in a controlled atmosphere consisting essentially of O.sub.2 and an inert gas to a temperature sufficient to decompose the precursor and produce the mixed metal oxide.

Abstract: A method is disclosed for purifying molybdenum which involves reducing a molybdenum compound selected from the group consisting of molybdenum trioxide, ammonium dimolybdate, and ammonium paramolybdate to molybdenum dioxide which is then water washed to remove potassium, and produce a purified molybdenum dioxide having a potassium content of no greater than about 30 weight ppm, followed by separating the wash water from the purified molybdenum dioxide.

Abstract: A whisker of molybdenum oxide in the form of a filament, rod or flake. Molybdenum oxide whiskers are produced by firing metallic molybdenum at a temperature of at least 400.degree. C., preferably at least 800.degree. C., in an atmosphere containing oxygen, or by firing an organic molybdenum compound in an atmosphere containing oxygen at a temperature which is at least equal to its thermal decomposition temperature. They are very strong crystals which are expected to be useful as a filler for plastics and for a variety of other applications.

Abstract: Molybdenite, MoS.sub.2, is completely converted into molybdenum dioxide, MoO.sub.2, by mixing MoS.sub.2 with petroleum or coal tar pitches and heating in air at 400.degree.-600.degree. F.

Abstract: The present invention relates to a heteropoly acid containing carbon as a hetero atom. This heteropoly acid is useful as catalysts or starting materials for various reactions, color forming material or counter electrode material for electrochromic display element or the like.

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: Processes are described for preparing pure ammonium molybdate from impure roasted molybdenum concentrates. An aqueous solution of nitric acid and ammonium nitrate is contacted with impure molybdenum concentrate to solubilize a major portion of the impurities. The resulting molybdenum concentrate is digested in ammonium hydroxide under conditions that maximize iron precipitation and removal. The resulting ammonium molybdate solution is separated from the sludge and further purified by chelating cation exchange resin in the ammonium form.

Abstract: Processes are described for preparing pure ammonium molybdate from impure roasted molybdenum concentrates. An aqueous solution of nitric acid, ammonium sulfate, and ammonium nitrate is contacted with impure molybdenum concentrate to solubilize a major portion of the impurities. The resulting molybdenum concentrate is digested in ammonium hydroxide under conditions that maximize iron precipitation and removal. The resulting ammonium molybdate solution is separated from the sludge and further purified by chelating cation exchange resin in the ammonium form.

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: Processes are described for preparing pure ammonium molybdate from impure roasted molybdenum concentrates. An aqueous solution of hydrochloric acid and ammonium nitrate is contacted with impure molybdenum concentrate to solubilize a major portion of the impurities. The resulting molybdenum concentrate is digested in ammonium hydroxide under conditions that maximize iron precipitation and removal. The resulting ammonium molybdate solution is separated from the sludge and further purified by chelating cation exchange resin in the ammonium form.

Abstract: A process is disclosed for recovering molybdenum from molybdenum disulfide. The process involves forming a slurry of the molybdenum disulfide in a solution of an alkali metal hydroxide, the amount of hydroxide being sufficient to react with at least a portion of the molybdenum disulfide to form an alkali metal molybdate and an alkali sulfate, heating the slurry in an oxidizing atmosphere at an elevated temperature and pressure and for a sufficient time to effect the conversion to the molybdate, and separating the pregnant liquor containing the molybdate from any residue. To the pregnant liquor is then added a sufficient amount of a hexamine to form a hexamine-molybdenum compound containing the major portion of the molybdenum, followed by adjusting the pH to from about 1.5 to about 3.8 to precipitate the major portion of the hexamine-molybdenum compound, and separating the compound from the resulting mother liquor.

Abstract: Processes are described for preparing pure ammonium molybdate from impure roasted molybdenum concentrates. An aqueous solution of sulfuric acid, ammonium sulfate, and ammonium persulfate is contacted with impure molybdenum concentrate to solubilize a major portion of the impurities. The resulting molybdenum concentrate is digested in ammonium hydroxide under conditions that maximize iron precipitation and removal. The resulting ammonium molybdate solution is separated from the sludge and further purified by chelating cation exchange resin in the ammonium form.

Abstract: A process is disclosed for recovering cobalt in a relatively pure form from an impure cobalt bearing material. The process involves digesting the material in hydrochloric acid to form a solution essentially all of the cobalt and some impurities and insoluble material containing the remainder of the impurities, separating the solution from the insolubles, adding an oxalate producing compound in an amount sufficient to subsequently convert essentially all of the cobalt to cobalt oxalate to the solution, adjusting the pH of the oxalate treated solution to from about 1.5 to about 2.0 with a base to precipitate the cobalt, and finally separating the precipitate from the resulting mother liquor.

Abstract: A method for treating process waste consisting of uranium hexafluoride, UF.sub.6, molybdenum hexafluoride, MoF.sub.6 and molybdenum oxytetrafluoride, MoOF.sub.4 is provided wherein the foregoing mixture is hydrolyzed in an aqueous solution of ammonium carbonate and ammonium hydroxide. The resulting mother liquor is digested at 60.degree.-80.degree. C. to drive off carbon dioxide and convert the ammonium uranyl carbonate, (NH.sub.4).sub.4 UO.sub.2 (CO.sub.3).sub.3 to ammonium diuranate, (NH.sub.4).sub.2 U.sub.2 O.sub.7. The pH is maintained above 9 to prevent premature precipitation of the molybdenum values as molybdic acid or uranyl molybdate.The ammonium diuranate which forms as a yellow solid is filtered, slurried in aqueous ammonium hydroxide, filtered and dried. The yield is quantitative. Pyrolysis results in conversion of the diuranate salt to uranium oxide, U.sub.3 O.sub.8, of suitable purity to be recycled in the uranium hexafluoride production process.

Abstract: The separation of dissolved and/or undissolved materials having different densities or different buoyancy densities can be effected with the aid of agents comprising solutions of true metatungstates. In the case of a separation of materials having different buoyancy densities by means of a density gradient centrifugation, the agent has the form of an aqueous solution of an alkali, ammonium or alkaline earth metal metatungstate and, if desired, may be augmented by the addition of at least one low molecular weight electrolyte. The agent can have a density of up to 3.1 g.cm.sup.-3, has a low viscosity at high concentrations, and is neutral and chemically insert. In the case of a separation of water-insoluble solid mixtures of different densities, the densities of the solutions of the true metatungstates can be increased up to 4.6 g.cm.sup.-3 by adding to the solutions high density materials such as sodium tungstate or tungsten carbide of suitable grain size so as to form a suspension.

Abstract: Processes are described for preparing pure ammonium molybdate from impure roasted molybdenum concentrates. An aqueous solution of nitric acid, ammmonium sulfate, and ammonium nitrate is contacted with impure molybdenum concentrate to solubilize a major portion of the impurities. The resulting molybdenum concentrate is digested in ammonium hydroxide under conditions that maximize iron precipitation and removal. The resulting ammonium molybdate solution is separated from the sludge and further purified by chelating cation exchange resin in the ammonium form.

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: The present invention relates to a method for the production of refractory oxide powders by pyrolyzing with laser energy a metal- and oxygen-containing organic chemical species characterized by the following properties: (a) some or all of the organic fragments (ligands) are bound to the metal by one or more metal-oxygen bonds, (b) the chemical species is able to absorb laser energy, preferably from a CO.sub.2 laser, in a vibrational mode, (c) the chemical species can be obtained in a gas state, at a temperature below the decomposition temperature.

Abstract: Processes are described for preparing pure ammonium molybdate from impure roasted molybdenum concentrates. An aqueous solution of nitric acid and ammonium nitrate is contacted with impure molybdenum concentrate to solubilize a major portion of the impurities. The resulting molybdenum concentrate is digested in ammonium hydroxide under conditions that maximize iron precipitation and removal. The resulting ammonium molybdate solution is separated from the sludge and further purified by chelating cation exchange resin in the ammonium form.

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: 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: 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: A method is described for the preparation of high surface area metal fluorides and metal oxyfluorides comprising reacting high surface area metal oxides with a fluorocarbon vapor wherein the fluorocarbon is selected from the group consisting of CH.sub.4-Q F.sub.Q wherein Q is 1 to 3 and totally or partially fluorinated C.sub.2 -C.sub.6 alkanes, alkenes and alkynes and C.sub.5 -C.sub.6 cyclic alkanes, preferably fluoroform (CHF.sub.3) wherein the metal oxides and the fluorocarbon vapors are contacted at a temperature of from about 300.degree. to about 800.degree. C., for a time sufficient to effect the essentially complete conversion of the metal oxides into metal fluorides or the partial conversion of the metal oxides into metal oxyfluorides.

Abstract: A process for preparing W, Mo or mixed metal oxides thereof by oxidizing a reduced metal oxide of the formula (NH.sub.m R.sub.4-m).sub.q.sup.+ MO.sub.p where each R is independently C.sub.1 -C.sub.20 aliphatic, C.sub.7 -C.sub.14 araliphatic or C.sub.3 -C.sub.8 cycloaliphatic with the proviso that adjacent R's, together with the nitrogen atom to which they are attached, may form a 5, 6 or 7 membered heterocyclic ring, m is an integer from 0 to 4, q is a number from about 0.001 to 1/3, M is W or Mo and p is a number from 2 to 3 with aqueous hydrogen peroxide. The so-treated reduced metal oxide is isolated and heated in an oxygen containing atmosphere to form metal oxides of the formula MO.sub.p.

Abstract: Molybdenum is recovered from an ammonium molybdate solution containing phosphate anions by digesting in an ammonium molybdate solution at least one water-soluble compound of at least one metal selected from the group consisting of aluminum, calcium, iron and magnesium in small but effective amounts to precipitate at least about 50% of the phosphate anions for a time sufficient to precipitate the phosphate anion, separating the phosphate precipitate from the ammonium molybdate solution, then acidifying the ammonium molybdate solution with at least one mineral acid selected from the group consisting of sulfuric acid and nitric acid to lower the pH value of the solution to between about 2.5 and about 4.5 to precipitate ammonium polymolybdate, and calcining the ammonium polymolybdate at a temperature below about 750.degree. C. to produce a molybdenum trioxide product.

Abstract: Molybdenum trioxide containing potassium is heated to a temperature sufficiently high (i.e. at least about 525.degree. C.) to render the potassium soluble in hot water, the heated trioxide is quenched to less than about 400.degree. C. at a rate of at least about 30.degree. C. per minute, the quenched trioxide is leached with hot water (between about 50.degree. C. and about 100.degree. C.) to leach the solubilized potassium and after liquid-solids separation the molybdenum trioxide is dissolved in ammonium hydroxide to form ammonium molybdates, which can be recovered from solution and then can be calcined to chemical grade molybdic oxide. The process is advantageously conducted in conjunction with the roasting of molybdenite.

Abstract: An improved process is described for the hydrometallurgical liquid phase oxidation of molybdenum disulfide ore concentrates, in which the reactants include in the range of from about 0.12 to about 1.68 mols of an alkali metal hydroxide, preferably sodium hydroxide, per mol of molybdenite, and the time of the reaction, the amount of the alkali metal hydroxide, and the reaction temperature and pressure are coordinated to achieve at least a 95% oxidation conversion of the molybdenum disulfide.

Abstract: An arc heater method and system for producing a high energy source characterized by a housing forming a mixing compartment, a plurality of arc heaters radially mounted on the housing and communicating with the mixing compartment, a reactor communicating with the downstream end of the mixing compartment with a reduced opening therebetween, inlet means at the downstream end of the compartment for introducing an oxidizable metal compound into the reactor, and means within the mixing compartment for flowing superheated gases from the arc heaters at the upstream end of the compartment and into the reactor.

Abstract: A process is provided for the manufacture of a tungstate salt, especially ammonium tungstate. The process comprises treating finely divided metallic tungsten and/or intermetallic iron/tungsten species with an aqueous solution in the presence of an oxidizing agent, such as oxygen or hydrogen peroxide. The solution contains cations which are ammonium and/or alkali-metal ions and anions which are hydroxide, carbonate and/or bicarbonate ions. The finely divided material generally contains no more than impurity quantities of alkaline earth metals. The process is useful in deriving tungsten values from wolframite ores, which are reduced prior to the aqueous treatment.