Abstract: A method for preparing large size beta-type ammonium tetramolybdate monocrystal particle includes industrial ammonium molybdate, ammonia, de-ionized water are used to prepare ammonium molybdate solution with concentration of 0.2˜0.6 g/ml; pH is adjusted to 5˜7, temperature is adjusted to the first temperature of 70˜90° C. to obtain the first ammonium molybdate solution; beta-type ammonium tetramolybdate crystal seed is put into crystallization container, and the first ammonium molybdate solution is poured in the crystallization container, to form crystallization system; the crystallization system stands still at room temperature, naturally cooling, the beta-type ammonium tetramolybdate crystal seed grows into large size beta-type ammonium tetramolybdate monocrystal particle. A beta-type ammonium tetramolybdate crystal seed is obtained by constant-temperature crystallization at 70˜90° C.

Abstract: The present invention discloses a method for effectively decomposing mixed wolframite and scheelite ore in an alkaline system, specifically comprising steps of: grinding mixed wolframite and scheelite ore, putting in an autoclave, adding an appropriate amount of water, and then adding sodium phosphate, sodium hydroxide and calcium fluoride for decomposition, and treating by solid-liquid separation to obtain crude sodium tungstate solution. The present invention has the advantage that the high-efficiency decomposition of the mixed wolframite and scheelite ore can be realized with low consumption of leaching agents. By this method, the mixed wolframite and scheelite ore can be directly treated by an existing tungsten smelting autoclave, with low leaching cost, high decomposition rate and easy industrial application.

Abstract: Methods of isolating tungsten and, in particular, methods of separating tungsten and vanadium are described herein. The methods can generally comprise treating a tungsten-containing material in aqueous solution with a reducing agent suitable for the reduction of pentavalent vanadium to one or more lower oxidation states of vanadium, such that the tungsten can be more readily separated from the vanadium, e.g., via solvent extraction. In certain embodiments, the methods disclosed herein can provide tungsten, vanadium, or both tungsten and vanadium in sufficient purities for commercial use.

Abstract: Disclosed are a hydrogen detection sensor and a method of manufacturing the same. The hydrogen detection sensor is manufactured by using hydrothermal synthesis method to synthesize a molybdenum oxide (MoO3) nanostructure, and irradiating UV light thereon to form an MoO3—Pd nanocomposite comprising the molybdenum oxide nanostructure with palladium (Pd) catalyst particles, and coating the MoO3—Pd nanocomposite on a substrate. As such, a visible color change from the MoO3 before and after exposure to hydrogen may be so obvious that the sensing or sensitivity of hydrogen and the long-term stability may be substantially improved. In addition, the manufacturing process is simple, and the manufacturing costs may be reduced.

Abstract: In a process for forming a bulk hydroprocessing catalyst by sulfiding a catalyst precursor made in a co-precipitation reaction, up to 60% of the metal precursor feeds do not react to form catalyst precursor and end up in the supernatant as metal residuals. In the present disclosure, the metals can be recovered in a chemical precipitation step, wherein the supernatant is mixed with at least one of an acid, a sulfide-containing compound, a base, and combinations thereof to precipitate at least 50% of metal ions in at least one of the metal residuals, wherein the precipitation is carried out at a pre-select pH. The precipitate is isolated and recovered, yielding an effluent stream. The precipitate and/or the effluent stream can be further treated to form at least a metal precursor feed which can be used in the co-precipitation reaction. The process generates an effluent to waste treatment containing less than 50 ppm metals.

Abstract: Provided are a method for producing sodium tungstate by supplying an oxidant made of sodium nitrate or sodium nitrite to bring a tungsten containing material and the oxidant into contact with each other in an atmosphere containing oxygen to thereby continuously produce a reaction product; a method for collecting tungsten using the method; and an apparatus for producing sodium tungstate. Also provided are a method for producing a sodium tungstate aqueous solution in which a reductant is introduced into a melt containing the above-described reaction product which is then dissolved in water; and a method for collecting tungsten using the method.

Abstract: The present invention provides a hydrothermal oxidation method for producing alkali metal dichromate from carbon ferrochrome, and the method comprises the following steps: formulating an initial reaction liquid by mixing carbon ferrochrome, an alkaline substance and water, in which the actual addition amount of the alkali is controlled smaller than the theoretically required amount; adding the initial reaction liquid into a reaction kettle, charging an oxidizing gas into the reaction kettle, and allowing the reaction to proceed for 0.5 to 3 h at a temperature of 150° C. to 370° C. and a pressure of 2 Mpa to 24 MPa; carrying out solid-liquid separation, cooling the resultant filtrate to a temperature of ?12° C. to ?20° C.

Abstract: A process for treating spent catalyst containing heavy metals, e.g., Group VIB metals and Group VIII metals is provided. In one embodiment after deoiling, the spent catalyst is treated with an ammonia leach solution under conditions sufficient to dissolve the group VIB metal and the Group VIII metal into the leaching solution, forming a leach slurry. After solid-liquid separation to recover a leach solution, chemical precipitation and solids repulping is carried out to obtain an effluent stream containing ammonium sulfate (Amsul), ammonium sulfamate, Group VB, Group VIB and Group VIII metals. Following sulfidation, the Group VIII metal is fully removed and Group VB and Group VI metals are partially removed from the Amsul stream.

Abstract: Disclosed is process for the separation of tungsten from molybdenum and more particularly from ammonium molybdate solutions. The method comprises dissolving technical grade molybdenum trioxide in an aqueous ammonium hydroxide solution and further adding certain metal generating compounds to the aqueous solution thereby generating a tungsten-containing precipitate. Calcium, iron and manganese are the preferred metal generating compounds of the invention. Certain temperature and pH values of the system, as disclosed, are preferred for the precipitation of the tungsten from the ammonia molybdate solution.

Abstract: A method inhibits the formation of zirconium molybdate precipitate in an aqueous solution containing the element molybdenum and the element zirconium by adding a chemical element selected from plutonium, tellurium, antimony and mixtures thereof with the aqueous solution. The method can be used for reprocessing used fuels with the element molybdenum and the element zirconium.

Abstract: Methods for recovering base metals, including, among other metals, molybdenum and nickel, from metal sulfides containing a Group VIB metal and a Group VIII metal. Generally, the methods comprise: contacting metal sulfides with a leaching solution containing ammonia and air to dissolve the metals into the leaching solution, forming a slurry containing soluble complexes of the metals, ammonium sulphate and solid residue containing ammonium metavanadate and any carbonaceous materials. The solid residue containing ammonium metavanadate and carbonaceous materials is then separated from the slurry and metal complexes are precipitated from the slurry by adjusting the pH. A second slurry may be formed comprising a second solid residue and a primary filtrate comprising ammonium sulfate solution that is substantially free of metals.

Abstract: A process for treating spent catalyst containing heavy metals, e.g., Group VIB metals and Group VIII metals is provided. In one embodiment after deoiling, the spent catalyst is treated with an ammonia leach solution under conditions sufficient to dissolve the group VIB metal and the Group VIII metal into the leaching solution, forming a leach slurry. After solid-liquid separation to recover a leach solution, chemical precipitation and solids repulping is carried out to obtain an effluent stream containing ammonium sulfate (Amsul), ammonium sulfamate, Group VB, Group VIB and Group VIII metals. Following sulfidation, the Group VIII metal is fully removed and Group VB and Group VI metals are partially removed from the Amsul stream.

Abstract: The present invention relates to a process for the conversion of cobalt(II)hydroxide into cobalt(III)oxidehydroxide (CoOOH) by reaction of the cobalt(II)hydroxide with oxygen in the presence of certain metal compounds. The invention further relates to the use of cobalt(III)oxidehydroxide thus prepared in the preparation of catalysts or catalysts precursors, especially catalysts or catalyst precursors for the conversion of synthesis gas into normally liquid and normally solid hydrocarbons and to normally liquid or solid hydrocarbons, optionally after additional hydrotreatment, obtained in such a conversion process.

Abstract: The invention relates to a process for recovering Group VIB metals from a catalyst, in particular a spent bulk catalyst, comprising one or more Group VIB metals and one or more Group VIII metals. Further, the invention relates to a solid Group VIB metal compound obtainable by the process according to the invention having the general formula H2XO4, wherein X=W1-yMoy, wherein y is between 0 and 1 and to its use in a process for the manufacture of a fresh catalyst.

Abstract: This invention relates to a method for producing chromates, especially for producing alkali metal chromates. The method comprises following steps: the obtaining of a mixture of alkali metal hydroxide, alkali metal chromate, and ferrous residue after the reaction of chromite ore with an oxidant in the reactor in the presence of molten salt or in aqueous solution of alkali metal hydroxide, the obtaining of a leaching slurry by leaching the reaction products with aqueous solution of alkali metal hydroxide, the separating of the primary chromate product from the leaching slurry, the obtaining of pure chromate crystal by purifying the primary chromate product. Both the primary chromate product and the pure chromate crystal can be used as the raw materials to manufacture other chromium compounds. Compared with the currently-used roasting method, the method has the advantages of decreasing the reaction temperature by about 700° C.

Abstract: A system and method for producing molybdenum oxide(s) from molybdenum sulfide are disclosed. The system includes a pressure leach vessel, a solid-liquid separation stage coupled to the pressure leach vessel, a solvent-extraction stage coupled to the solid-liquid separation stage, and a base stripping stage coupled to the solvent-extraction stage. The method includes providing a molybdenum sulfide feed, subjecting the feed to a pressure leach process, subjecting pressure leach process discharge to a solid-liquid separation process to produce a discharge liquid stream and a discharge solids stream, and subjecting the discharge liquid stream to a solvent extraction and a base strip process.

Abstract: A process for producing molybdenum compounds, from spent molybdenum catalyzers, industrial residues and metal alloys, particularly an integrated process for reclaiming molybdenum, vanadium, nickel, cobalt, aluminum and other metals, starting with the treatment of exhausted catalyzers, industrial residues and metal alloys, principally from petroleum de-sulfurization catalyzers; the molybdenum trioxide is obtained by precipitation of ammonium octamolybdate and its calcination. Starting from molybdenum trioxide, other compounds derived from molybdenum can be obtained, as sodium molybdate, molybdenum disulfite and ammonium molybdate.

Abstract: The invention relates to a process for recovering Group VIB metals from a catalyst, in particular a spent bulk catalyst, comprising one or more Group VIB metals and one or more Group VIII metals. Further, the invention relates to a solid Group VIB metal compound obtainable by the process according to the invention having the general formula H2XO4, wherein X=W1-yMoy, wherein y is between 0 and 1 and to its use in a process for the manufacture of a fresh catalyst.

Abstract: Provided is a cathode composition for lithium secondary battery that includes a lithium-chromium-titanium-manganese oxide that has the formula Li[Li(1-x)/3CrxTi(2/3)yMn2(1-x-y)/3]O2 where 0?x?0.3, 0?y?0.3 and 0.1?x+y?0.3, and layered a-LiFeO2 structure. A method of synthesizing the lithium-chromium-titanium manganese oxide includes preparing a first mixed solution by dispersing titanium dioxide (TiO2) in a mixed solution of chrome acetate (Cr3(OH)2(CH3CO2)7) and manganese acetate ((CH3CO2)2Mn.4H2O), adding a lithium hydroxide (LiOH) solution to the first mixed solution to obtain homogeneous precipitates, forming precursor powder that has the formula Li[Li(1-x)/3CrxTi(2/3)yMn2(1-x-y)/3]O2 where 0?x?0.3, 0?y?0.3 and 0.1?x+y?0.3 by heating the homogeneous precipitates, and heating the precursor powder to form oxide powder having a layered structure.

Abstract: A process for recovery of hexavalent chromium from waste streams. The method includes providing a waste stream containing hexavalent chromium, reacting a soluble non-toxic precipitating reagent with the hexavalent chromium to form an insoluble precipitating reagent-chromate precipitate, and recovering the insoluble precipitating reagent-chromate precipitate. It may optionally include reacting the insoluble precipitating reagent-chromate precipitate with an acidic solution to form an insoluble precipitating reagent precipitate and a soluble hexavalent chromium compound, and recovering the soluble hexavalent chromium compound. The process may also include reacting the insoluble precipitating reagent precipitate with a solubilizing reagent to form the soluble non-toxic precipitating reagent.

Abstract: Disclosed is a device and method of use for detecting polyvalent analytes such as antibody to the AIDS virus, utilizing an inverse sandwich method. The test device comprises a first substance having an epitope, bound to a label and capable of moving within the test device. The test device further comprises a second substance immobilized to the test device and spatially separated from the first substance. The second substance has an epitope substantially similar to the epitope of the first substance. Upon application to the test device, the polyvalent analyte binds to the first substance and moves within the test device to the location of the second substance with both polyvalent analyte and first substance are immobilized at location of the second substance. Polyvalent analyte is detected by the presence of the label at the location of the second substance. Also disclosed is a control substance for use with the device that can be used to determine completion of the test and viability of the device.

Abstract: One or more metal salts of at least one iron group metal containing organic groups are dissolved in at least one polar solvent and complex bound with at least one complex former comprising functional groups in the form of OH or NR3, (R═H or alkyl). In addition, at least one insoluble, reducible salt of at least one iron group metal is suspended in the solution. Hard constituent powder and, optionally, a soluble carbon source are added to the solution. The solvent is evaporated and the powder mass is heat treated in inert and/or reducing atmosphere. As a result, a powder mixture is obtained which, after addition of a pressing agent, can be compacted and sintered according to standard practice to form a body containing hard constituents in a binder phase.

Abstract: Molybdenum trioxide is produced from molybdenite by a pressure oxidation process comprising of the steps of forming an aqueous slurry of molybdenite, pressure oxidizing the slurry to form soluble and insoluble molybdenum species, converting the insoluble molybdenum species to soluble molybdenum species by alkaline digestion, separating the soluble molybdenum species from insoluble residue contaminants (if present), removing the molybdenum species from the aqueous media through solvent extraction, and recovering the molybdenum values as molybdenum trioxide from the organic solvent. Low grade molybdenite concentrates, including concentrator slimes containing talc and sericite, can be used as a feed. The process produces technical grade molybdenum trioxide.

Abstract: A process for preparing a compound that includes the steps of: (a) preparing a solution comprising (i) a chromium source, (ii) a manganese source, (iii) a lithium source, and (iv) an oxygen source, where the relative amounts of each of the sources is selected to yield, following step (c), a compound having the formula Li.sub.y Cr.sub.x Mn.sub.2-x O.sub.4+z where y.gtoreq.2, 0.25<x<2, and z.gtoreq.0; (b) treating the solution to form a gel; and (c) heating the gel under an inert atmosphere for a time and at a temperature sufficient to yield a compound having the formula Li.sub.y Cr.sub.x Mn.sub.2-x O.sub.4+z where y.gtoreq.2, 0.25<x<2, and z.gtoreq.0. The invention also features a compound having the formula Li.sub.y Cr.sub.x Mn.sub.2-x O.sub.4+z where y>2, 0.25<x<2, and z.gtoreq.0, and an electrode composition containing this compound.

Abstract: A method for producing purified MoO.sub.3 from MoS.sub.2. MoS.sub.2 is initially oxidized to generate an impure MoO.sub.3 product containing metallic contaminants and molybdenum sub-oxides. This product is then slurried with a primary water supply to yield a first slurry in which part of the contaminants are dissolved. Preferred slurry temperatures are 25.degree.-97.degree. C. The resulting solid intermediate MoO.sub.3 product is removed from the slurry leaving the dissolved contaminants. Next, the intermediate MoO.sub.3 product is slurried with a secondary water supply to yield a second slurry in which the remaining contaminants are dissolved. Second slurry temperatures of 150.degree.-250.degree. C. are employed in the presence of an oxygen-containing gas. These conditions oxidize molybdenum sub-oxides to yield MoO.sub.3. The resulting purified solid MoO.sub.3 product is then removed from the second slurry. This process is highly efficient and avoids using liquid reagents other than water (including acids).

Abstract: A method for producing MoO.sub.3 from MoS.sub.2. MoS.sub.2 is combined with water to form a slurry which is then combined with at least one oxygen-containing oxidizing gas in a reaction chamber in order to initiate oxidization and conversion of MoS.sub.2 into MoO.sub.3. The oxidization and conversion of MoS.sub.2 into MoO.sub.3 is terminated before complete conversion of MoS.sub.2 to MoO.sub.3 takes place in order to generate a solid reaction product comprising MoO.sub.3 and unreacted MoS.sub.2 in combination with a residual liquid product comprising dissolved Mo therein. The oxidization and conversion process may be terminated when about 70-95% by weight MoS.sub.2 has been converted to MoO.sub.3. Thereafter, the solid reaction product is separated from the residual liquid product and the residual liquid product combined with at least one extractant in order to generate a liquid fraction containing dissolved Mo.

Abstract: A method is provided whereby tungsten values are recovered from ferrotungsten by completely oxidizing the ferrotungsten at high temperatures in an oxygen atmosphere followed by digestion with sodium hydroxide to form soluble sodium tungstate. The sodium tungstate is then purified by conventional means. The method may be used to recover at least about 90% of the tungsten values present in the ferrotungsten.

Abstract: An aqueous epoxidation process stream containing molybdenum and sodium values is incinerated and an aqueous solution containing molybdenum and sodium is recovered, acidified and reacted with a calcium compound without first adding base to form solid CaMoO.sub.4 which is separated.

Abstract: A grate assembly for a fluidized bed boiler comprises a number of parallel sparge pipes or the like extending side-by-side in a substantially horizontal plane and provided with elements for supplying fluidizing air from within the sparge pipes or the like into a combustion chamber located above the grate assembly. The discharge of some of the fluidized bed materials is effected through an aperture system formed between the adjacent sparge pipes into a receiver unit fitted below the grate assembly. The sparge pipes are provided with a cooling medium circulation by means of a duct assembly.

Abstract: Process for recovering and re-using cobalt and tungsten from reaction liquors, in which said reaction liquors are treated:a) With an alkali-earth metal hydroxide in order to precipitate cobalt and tungsten, and the resulting precipitate is subsequently treated with a strong mineral acid in order to be able to dissolve the cobalt salt and separate it from H.sub.2 WO.sub.4 precipitate; orb) With an alkali metal hydroxide in order to precipitate and separate Co(OH).sub.2, and the resulting alkaline solution is then treated with an alkali-earth metal compound which is filtered and treated with a strong mineral acid in order to obtain H.sub.2 WO.sub.

Abstract: According to the invention there is now provided a simple method of preparing a powder containing WC and cobalt and/or nickel. APT-powder and a powder of a basic salt of cobalt and/or cobalt are mixed in water or in mixed solvents. The suspension is stirred to react at temperatures ranging from room temperature to the boiling point of the solution whereby a precipitate is formed, which precipitate is filtered off, dried and finally reduced to a metallic powder.

Abstract: An aqueous epoxidation process stream containing molybdenum and sodium values and organics is treated for organics removal as by incineration and an aqueous solution containing molybdenum and sodium is recovered, acidified and reacted with a calcium compound to form solid CaMoO.sub.4 which is separated.

Abstract: A process for recovery of chromium in an aqueous solution comprising converting the chromium to chromyl chloride, separating the chromyl chloride from the aqueous solution, either as a heavy underlayer, or by extraction into a solvent, purifying the chromyl chloride, hydrolyzing the purified chromyl chloride to form a solution, and drying or precipitating the solution to form chromium, either as chromic acid or a chromate salt.

Abstract: A process for treatment of hazardous liquid waste comprising trace amounts of hazardous elements in solution as oxyanions by oxyanion fixation within ettringite and related minerals. In accordance with the disclosed process, reagents for forming ettringites are mixed with the waste stream resulting in the formation of oxyanion-substituted ettringite and related materials. The resulting ettringite and related minerals are separated by filtration from the liquid. Thereafter, the liquid, having an elevated pH, is neutralized by carbon dioxide sparging resulting in precipitation of excess reagents in the liquid. Thereafter, the precipitates are filtered, producing a clean liquid.

Abstract: Epoxidate from the molybdenum catalyzed epoxidation of an olefin such as propylene with a hydroperoxide such as ethylbenzene hydroperoxide is treated with 2 to 15 times the stoichiometric equivalent of aqueous base such as sodium hydroxide to form Na.sub.2 MoO.sub.4 and the resulting mixture is phase separated to separate an organic phase reduced in molybdenum and a net aqueous stream containing removed molybdenum, the mass ratio of the organic phase to the net aqueous stream being 450-3,000/I.

Abstract: A process for recovering valuable metals from a waste catalyst based on an alumina carrier includes (a) roasting the waste catalyst at a temperature range of 400.degree. to 1,000.degree. C. to obtain a roasted product; (b) preparing a reduction dissolution by dissolving the roasted product with sulfuric acid in the presence of a metal as a dissolution catalyst; (c) separating a large part of the aluminum from the reduction dissolution solution and recovering aluminum as ammonium aluminum sulfate from the solution, optionally after subjecting the reduction dissolution solution to a treatment of removing iron; (d) extracting molybdenum as a molybdate by solvent extraction from the solution after separating and recovering aluminum from the solution; (e) extracting vanadium as a vanadate by solvent extraction from the solution obtained as a residue after extracting molybdenum; and (f) recovering nickel and cobalt each as a hydroxide from the extraction residue after recovering vanadium.

Abstract: Disclosed is a method of removing soluble vanadium from an aqueous stream containing sodium chromate or sodium bichromate. The liquor is passed over a water-insoluble trivalent chromium compound, and the vanadium in the liquor is extracted from the liquor onto the trivalent chromium compound. The process is especially useful in removing vanadium from a recycled concentrated sodium bichromate liquor to prevent the buildup of vanadium therein.

Abstract: A process for the preparation of sodium dichromate and sodium dichromate solutions by alkaline oxidizing roasting of chromium ores, leaching resulting roast with water, adjustment of the pH to 7 to 9.5, removal of the insoluble constituents by filtration, a sodium monochromate solution containing 300 to 400 g/l of Na.sub.2 CrO.sub.4 being obtained, conversion of the monochromate ions of this solution into dichromate ions by addition of an acid and/or by electrolysis and/or by reaction with carbon dioxide under pressure and crystallization of sodium dichromate by concentration of this solution. The improvement wherein before the conversion into a sodium dichromate solution, the sodium monochromate solution is concentrated to contents of 700 to 1000 g/l of Na.sub.2 CrO.sub.4, the monochromatic ions, the solution is subsequently freed as far as possible from sodium sulphate by cooling to a temperature of below 0.degree. C.

Abstract: Aluminum is removed from ammonium molybdate solution by the use of Mg.sup.+2 in the solution to precipitate out the aluminum.

Abstract: This invention relates to a method for toxicity comprehensive elimination of chrome residues, comprising adding water to chrome residues, wet-grinding the same to a thick liquid, letting it react with dilute hydrochloric acid, and letting the filtrate obtained react with an additive containing barium, with sulfuric acid or magnesium sulfate, and with cream of lime or soda, so as to realize a comprehensive extraction and utilization of various elements. The hydrochloric acids can be circulated, and the filter residues can be used for iron-smelting and brick-making. By means of this method, it is possible not only to completely and permanently eliminate the toxicity of the residues, but also to realize a comprehehsive utilization of the residue resources.

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 process for the production of sodium dichromate comprising reacting sodium chromate with acids, the acids being sulfuric acid and NaHSO.sub.4 formed as a waste product in the production of CrO.sub.3 and thus being contaminated with chromium compounds, adding PO.sub.4 ions in excess to the NaHSO.sub.4 contaminated with chromium compounds and precipitating the Cr(III) present therein as CrPO.sub.4 at a temperature of 50.degree. to 100.degree. C. and at a pH value of 3 to 6.

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: A process for preparing a tungsten-188/rhenium-188 generator having a tungstate matrix containing W-188 produced by irradiating tungsten-186 in the tungstate compound. High activity, carrier-free rhenium-188 may be obtained by elution. Substrates for further purifying the rhenium-188 eluate are also described.

Abstract: A method is disclosed for purifying molybdenum which involves adding to an ammoniacal ammonium molybdate solution containing the impurities of phosphorus and arsenic with the phosphorus concentration being from about 0.01 to about 0.12 g/l, a soluble magnesium salt to form a precipitate comprising magnesium ammonium salts of the phosphorus and arsenic, and to form a purified ammonium molybdate solution. The amount of the magnesium salt is sufficient to result in a concentration of from about 0.005 to about 0.04 moles/l in the ammoniacal ammonium molybdate solution. The resulting purified ammonium molybdate contains no greater than about 0.01 g P/l. The precipitate is separated from the purified solution which is then contacted with a chelating cation exchange resin supplying a sufficient amount of a cation to result in removal of the major portion of the magnesium ions from the purified solution and form a further purified ammonium molybdate solution.

Abstract: The present invention relates to a simple process for the recovery of pure tungsten at a high yield from cemented tungsten carbide or tungsten alloys scrap. According to the invention the process consists of a series of steps characterized by certain critical parameters.

Abstract: A process is disclosed for producing pure molybdenum which involves contacting a molybdate solution with a true liquid alkaloid in an amount sufficient to form an alkaloid-molybdenum compound with essentially all of the molybdenum. The resulting alkaloid-treated solution is adjusted to a pH of from about 2 to 4 to form a precipitate consisting essentially of the compound and a mother liquor. The precipitate is then separated from the mother liquor and dissolved in ammonium hydroxide to form a two phase system consisting essentially of an alkaloid phase and a molybdenum phase followed by separation of the two phases. A pure ammonium molybdate compound is then crystallized from the molybdenum phase.

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: 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 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.