Abstract: The sulphur emissive capability, on combustion, of coke which is formed during upgrading of sulphur-containing heavy crude oils, including oil sands bitumen, and residua, is decreased by the addition of calcium carbonate, preferably in the form of limestone, to the heavy crude oil prior to coking. The presence of the limestone leads to an increased yield of liquid distillates from the coking process under preferred coking conditions. Ash remaining after combustion of the coke may be leached to recover nickel and vanadium values therefrom.

Abstract: The sulphur emissive capability, on combustion, of coke which is formed during upgrading of sulphur-containing heavy crude oils, including oil sands bitumen, or residua is decreased by the addition of slaked lime or calcium oxide to the heavy crude oil prior to coking. The presence of the slaked lime or calcium oxide leads to an increased yield of liquid distillates at coking temperatures of about 450.degree. to about 500.degree. C. Ash remaining after combustion of the coke may be leached to recover nickel and vanadium values therefrom.

Abstract: A process for removing nickel, cobalt, molybdenum, and vanadium from spent hydroprocessing catalyst particles by roasting the catalyst at between 400.degree. C. and 600.degree. C. and leaching the catalyst particles with an aqueous solution of ammonia and an ammonium salt.

Abstract: A tungsten-containing catalyst associated with coke containing vanadium and nickel is recovered by a method which includes steam gasification, low temperature burning to remove at least a portion of the coke and selective extraction of the nickel and vanadium.

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: A process is provided for recovering metal values from spent hydrodesulfurization catalyst, the process comprising forming in a pressure reactor an aqueous slurry of finely divided spent catalyst and sodium carbonate, the spent catalyst containing by weight about 2 to 10% Mo, up to about 12% V (e.g., about 2 to 10%), about 0.5 to 4% Co, up to about 10% Ni (e.g., about 0.5 to 5%), occluded oil, coke, sulfide sulfur and the balance essentially alumina. The amount of sodium carbonate employed is at least sufficient under oxidizing conditions to convert molybdenum and any vanadium present to soluble Na.sub.2 MoO.sub.4 and NaVO.sub.3 and to neutralize SO.sub.3 produced during oxidation, the amount of sodium carbonate being at least that required stoichiometrically. The slurry is heated to a temperature of about 200.degree. C. to 350.degree. C. (e.g., 275.degree. C. to 325.degree. C.) and a pressure of about 800 psig to 2500 psig (e.g.

Abstract: Tantalum is recovered from an impure source containing niobium, tungsten, titanium, iron, and other impurities by a process comprising mixing the impure source with an alkali metal carbonate, drying the resulting mixture, heating the dried mixture to convert the tungsten to a soluble form, leaching to solubilize the tungsten, digesting the resulting leached solids containing tantalum in hydrochloric acid to solubilize iron values and a portion of the titanium values, dissolving the leached solids containing tantalum values in hydrofluoric acid, adjusting the pH of the resulting solution to form a first tantalum precipitate, dissolving the first tantalum precipitate in oxalic acid adjusting the pH to form a second tantalum precipitate, dissolving and digesting the second tantalum precipitate in hydrochloric acid solution to form a third tantalum precipitate of high purity.

Abstract: Niobium and tantalum containing pyrochlore is recovered from high silicate gangue content ore with good selectivity and yield employing collectors of formula ##STR1## wherein R.sub.1, R.sub.2 and R.sub.3 are independently 8 to 16 carbon straight or branched chain alkyl groups, at pH 1.5 to 6.5.

Abstract: A process is disclosed for producing a high purity tantalum precipitate from an impure source by dissolving in a first hydrofluoric acid solution and digested to form a first precipitate of tantalum which dissolved in hydrochloric acid. The resulting solution is heated to form a second precipitate of tantalum which is dissolved in another hydrofluoric acid solution and digested to form a third precipitate of tantalum. The third precipitate of tantalum is then dissolved in an oxalic acid solution with the pH being adjusted to form another tantalum precipitate which is converted to tantalum oxide.

Abstract: A process is provided for extracting vanadium values from a vanadium-bearing ore in which a carbonaceous material is added to a salt roast mixture containing ore and an alkali metal salt, e.g., NaCl. The mixture is subjected to roast temperatures (e.g., 825.degree. C.) for a period of time sufficient to burn off substantially all of the carbon in the mixture. The carbonaceous material is preferably a vanadium-containing carbon source, e.g., residue from the combustion of heavy petroleum oil.

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: Vanadium values are recovered from sulphur-containing cokes and ashes derived from heavy oils by a novel process comprising heating in the presence of alkali metal carbonate, contacting the resulting solid residue with water to form a leach and recovering the vanadium values dissolved therein. The amount of alkali metal carbonate used is at least sufficient to convert the vanadium values present in the raw material into alkali metal vanadate, but insufficient to react in addition with all of the sulphur values therein. The heating step solubilizes only alkali metal vanadate and thus the leach solution is substantially free of contaminating substances.

Abstract: Spent catalysts removed from a catalytic hydrogenation process for hydrocarbon feedstocks, and containing undesired metals contaminants deposits, are regenerated. Following solvent washing to remove process oils, the catalyst is treated either with chemicals which form sulfate or oxysulfate compounds with the metals contaminants, or with acids which remove the metal contaminants, such as 5-50 W % sulfuric acid in aqueous solution and 0-10 W % ammonium ion solutions to substantially remove the metals deposits. The acid treating occurs within the temperature range of 60.degree.-250.degree. F. for 5-120 minutes at substantially atmospheric pressure. Carbon deposits are removed from the treated catalyst by carbon burnoff at 800.degree.-900.degree. F. temperature, using 1-6 V % oxygen in an inert gas mixture, after which the regenerated catalyst can be effectively reused in the catalytic process.

Abstract: A process for recovering one or more non-radioactive transition metal compounds from an ore containing one or more compounds of said transition metal or metals and further containing at least one complex of a member selected from the group consisting of uranium, thorium, radium, titanium, and rare earth metals, which comprises decomposing said ore in crushed condition by means of an acid so that a portion of the ore is brought into solution in a liquid phase and another portion of the ore remains in a solid phase, said compound or compounds of the transition metal or metals to be recovered passing into only the liquid or into only the solid phase, the uranium in the crushed ore being treated so as to cause substantially all of said uranium to be present in an oxidation state in which it cannot, during the decomposition step, pass into the phase containing the transition metal compound or compounds.

Abstract: A process for recovering one or more nonradioactive transition metal compounds from an ore containing one or more compounds of said transition metal or metals and further containing at least one complex of a member selected from the group consisting of uranium, thorium, radium, titanium, and rare earth metals, which comprises decomposing said ore in crushed condition by means of an acid so that a portion of the ore is brought into solution in a liquid phase and another portion of the ore remains in a solid phase, said compound or compounds of the transition metal or metals to be recovered passing into only the liquid or into only the solid phase, the uranium in the crushed ore being treated so as to cause substantially all of said uranium to be present in an oxidation state in which it cannot, during the decomposition step, pass into the phase containing the transition metal compound or compounds.

Abstract: Vanadium and nickel values are selectively recovered from a petroleum coke residue by slurrying the coke in an aqueous solution of sodium carbonate providing an excess of the stoichiometric amount of sodium for formation of sodium vanadate and sodium sulfate, and then digesting the slurry at moderately elevated temperature in a pressurized autoclave under an oxygen overpressure supplying at least the stoichiometric amount of oxygen based on the vanadium and sulfur content of the slurry and advantageously sufficient additional oxygen to provide the thermal requirements of the digestion step by oxidation of carbon. In a continuous embodiment, the feed slurry temperature and feed solids content are adjusted according to a substantially inversely correlated relationship. The digestion temperature for a given total pressure and gas flow rate in the autoclave is adjusted to generate a pregnant liquor containing about 20 gpl to about 100 gpl of vanadate (V.sub.2 O.sub.

Abstract: The present invention relates to a process for the recovery of uranium and other minerals from uranium ore where at least part of the uranium is present as refractory uranium-mineral complexes, comprising subjecting the uranium ore to mild oxidative carbonate leach fluid to dissolve and remove readily soluble uranium minerals, subsequently subjecting the uranium ore to an oxidative chemically severe leaching system to dissolve and remove the refractory uranium-mineral complexes, and separating and recovering the uranium and other mineral species in the leachate fluids. The process may be applied to in-situ uranium leaching operations or to surface leaching operations.

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: Metal constituents are recovered from the heavy bottoms produced during the liquefaction of coal and similar carbonaceous solids in the presence of a catalyst containing a metal capable of forming an acidic oxide by burning the heavy bottoms in a combustion zone at a temperature below the fusion temperature of the ash to convert insoluble metal-containing catalyst residues in the bottoms into soluble metal-containing oxides; contacting the oxidized solids formed in the combustion zone with an aqueous solution of a basic alkali metal salt to extract the soluble metal-containing oxides in the form of soluble alkali metal salts of the metal-containing oxides and recycling the soluble alkali metal salts to the liquefaction zone. In a preferred embodiment of the invention, the bottoms are subjected to partial oxidation, pyrolysis, coking, gasification, extraction or a similar treatment process to recover hydrocarbon liquids and/or gases prior to the burning or combustion step.

Abstract: Vanadium values are recovered from cokes and ashes derived from heavy oils by a novel process comprising heating in the presence of alkali metal sulphate, contacting the resulting solid residue with water and recovering the vanadium values dissolved therein.

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.

Abstract: Disclosed is a process for recovering chromium, vanadium, molybdenum, and tungsten from secondary resources such as alloy scrap comprising a refractory metal and base metals such as cobalt nickel, iron, and copper. The scrap is calcined with sodium carbonate in air to convert the refractory metal values to MoO.sub.4.sup..dbd., VO.sub.4.sup..tbd., WO.sub.4.sup..dbd., CrO.sub.4.sup..dbd., and the base metals to water insoluble oxides. A leach of the calcined materials produces a pregnant liquor rich in refractory metals which, after separation of the vanadium, molybdenum and tungsten values, is treated with CO, CHOO.sup.-, CH.sub.3 OH, or HCHO to reduce Cr.sup.+6 to Cr.sup.+3. The carbonate and bicarbonate salts produced as a byproduct of the reduction are recycled to the calcination stage.As a result of the V, W, and Mo partition, a mixed solid comprising CaO.multidot.nV.sub.2 O.sub.5, CaMoO.sub.4, and CaWO.sub.4 is produced.

Abstract: In a process for producing tantalum concentrates from ores containing tantalum oxides, tantalic acid or its salts together with rutile type titanium dioxide in mixed crystals, the ores are treated in a sulfuric acid of a concentration not lower than 50% by weight with heating at a temperature from 200.degree. C. to the boiling point of said sulfuric acid, and then the above-treated products are treated with a reducing agent in an aqueous solution of sulfuric acid of a concentration lower than 50% by weight to dissolve the titanium component to thereby obtain tantalum concentrates as solid products.

Abstract: Disclosed is a process for recovering chromium, vanadium, molybdenum, and tungsten from secondary resources such as alloy scrap comprising a refractory metal and base metals such as cobalt, nickel, iron, and copper. The scrap is calcined with sodium carbonate in air to convert the refractory metal values to MoO.sub.4.sup.=, VO.sub.4.sup..ident., WO.sub.4.sup.=, and CrO.sub.4.sup.= and the base metals to water insoluble oxides. A leach of the calcined materials produces a pregnant liquor rich in refractory metals which, after separation of the vanadium, molybdenum and tungsten values, is treated with CO, CHOO.sup.-, CH.sub.3 OH, or HCHO to reduce Cr.sup.+6 to Cr.sup.+3. The carbonate and bicarbonate salts produced as a byproduct of the reduction are recycled to the calcination stage.As a result of the V, W, and Mo partition, a mixed solid comprising CaO.nV.sub.2 O.sub.5, CaMoO.sub.4, and CaWO.sub.4 is produced.

Abstract: Disclosed is a process for recovering chromium, vanadium, molybdenum, and tungsten from secondary resources such as alloy scrap comprising a refractory metal and base metals such as cobalt, nickel, iron, and copper. The scrap is calcined with sodium carbonate in air to convert the refractory metal values to MoO.sub.4.sup.=, VO.sub.4.sup..ident., WO.sub.4.sup.=, and CrO.sub.4.sup.= and the base metals to water insoluble oxides. A leach of the calcined materials produces a pregnant liquor rich in refractory metals which, after separation of the vanadium, molybdenum and tungsten values, is treated with CO, CHOO.sup.- CH.sub.3 OH, or HCHO to reduce Cr.sup.+6 to CR.sup.+3. The carbonate and bicarbonate salts produced as a byproduct of the reduction are recycled to the calcination stage.As a result of the V, W, and Mo partition, a mixed solid comprising CaO.nV.sub.2 O.sub.5, CaMoO.sub.4, and CaWO.sub.4 is produced.

Abstract: A process for the oxidizing attack at high temperature of ores containing at least one metal belonging to the group formed by uranium, vanadium and molybdenum, by means of an aqueous liquor containing a majority of sodium bicarbonate and a minority of sodium carbonate according to a ratio by weight of sodium bicarbonate to sodium carbonate of at least 1.5, in the presence of free oxygen injected into the reaction medium, this medium being maintained at a temperature of between 160.degree. C. and 300.degree. C. for at most six hours.

Abstract: A process for the removal of metal poisons such as nickel, iron and/or vanadium from a hydrocarbon conversion catalyst which includes the step of contacting the catalyst with a sulfur-containing compound to convert at least a portion of the metals on the catalyst to a sulfur-containing metal compound. The weight % sulfur on the thus treated catalyst is controlled to about 40-90%, preferably about 40-75%, of the weight % of the total nickel, vanadium and iron on the catalyst. Preferably, the sulfur-containing compound is hydrogen sulfide in admixture with a reducing gas such as hydrogen and/or carbon monoxide. This step facilitates metal removal in subsequent processing steps.

Abstract: Disclosed is a process for recovering chromium, vanadium, molybdenum, and tungsten from secondary resources such as alloy scrap comprising a refractory metal and base metals such as cobalt, nickel, iron, and copper. The scrap is calcined with sodium carbonate in air to convert the refractory metal values to MoO.sub.4.sup..dbd., VO.sub.4.sup..tbd., WO.sub.4.sup..dbd., and CrO.sub.4.sup..dbd. and the base metals to water insoluble oxides. A leach of the calcined materials produces a pregnant liquor rich in refractory metals which, after separation of the vanadium, molybdenum and tungsten values, is treated with CO, CHOO.sup.-, CH.sub.3 OH, or HCHO to reduce Cr.sup.+6 to Cr.sup.+3. The carbonate and bicarbonate salts produced as a byproduct of the reduction are recycled to the calcination stage.As a result of the V, W, and Mo partition, a mixed solid comprising CaO.nV.sub.2 O.sub.5, CaMoO.sub.4, and CaWO.sub.4 is produced.

Abstract: The process comprises oxidation of alkali-metal-containing carbonaceous products at a temperature of at least 800.degree. C. in a fluidized bed of fire-proof particles capable of trapping or fixing the metal elements.

Abstract: The removal of metals, especially vanadium, from spent hydrofining catalyst is accomplished by a two-step process. Treatment with a gaseous sulfur-containing reagent brings the metals to the surface of the catalyst and converts them to sulfides, which are then efficiently removed by contact with a heteropoly acid such as molybdophosphoric acid. Treatment of deactivated hydrodesulfurization catalysts such as Co-Mo supported on alumina by this process results in substantially complete regeneration of catalytic activity.

Abstract: Contacting deactivated hydrodesulfurization catalyst, such as Co-Mo supported on alumina, with a heteropoly acid, such as molybdophosphoric acid or tungstosilicic acid, in pH range of about 1 to 3 and temperature range of about 20.degree. to 80.degree. C., results, before any coke is burned off the catalyst, in selective abstraction of vanadium and nickel, removal of sulfur, increase in surface area, and increase in pore volume of the catalyst. Subsequent cobalt doping of demetallized catalyst followed by calcination promotes decoking, additional sulfur removal and additional increase in surface area and pore volume. The process results in substantially complete regeneration of catalytic activity.

Abstract: Contacting deactivated hydrodesulfurization catalyst, such as Co-Mo supported on alumina, with a heteropoly acid, such as molybdophosphoric acid or tungstosilicic acid, to which dilute hydrogen peroxide is added, results in a significant enhancement in the rate and extent of carbon and metals removal. Forms of deposited vanadium intractable by other treatments are also removed. The process results in substantially complete regeneration of catalytic activity.

Abstract: Poly[di-1,2-(diazinylidene)-ethene-1,2-diols] having the structure:X--C.sub.4 H.sub.2 N.sub.2 --C(OH).dbd.C(OH)--C.sub.4 H.sub.2 N.sub.2 --C(OH) ].sub.n C(OH)--C.sub.4 H.sub.2 N.sub.2 --Yin which the C.sub.4 H.sub.2 N.sub.2 group is a diazinylidene diradical having each C(OH) group adjacent (ortho) to one but not two ring nitrogen atoms and not adjacent (ortho) to each other; X and Y are terminal formyl (CHO) groups or groups derived from them by oxidation; and n has a value of zero to seven--are prepared by a cyanide ion catalyzed condensation of pyrazine-2,5-dicarboxaldehyde, pyridazine-3,6-dicarboxaldehyde; or pyrimidine-4,6-dicarboxaldehyde as the only aldehydes which provide the requisite structures. The polymers form complexes with metal ions including manganese, which is insoluble, and vanadium, which is soluble.

Abstract: A method for producing alkali metal chromates by a single roast of chrome ores without the use of calcium oxide is disclosed. A double roast embodiment is also contemplated for obtainment of enhanced yields. The pollution and hygiene problems associated with the use of lime are substantially eliminated and only negligible amounts of alumina are found in the product chromate liquors without employing steps previously thought necessary. These advantages are achieved by controlling (1) the Bichromate Equivalent: aluminum oxide ratio in the mix, (2) the amount of alkali metal salts added to the mix, (3) the roasting time, (4) the composition and alkalinity of the liquor used for leaching the roast, and (5) the temperature employed. Recovery of vanadium values from the alkali metal chromate liquors is also disclosed.

Abstract: Petroleum coke containing inorganic compounds including vanadium is gasified with steam in the presence of an alkali metal salt gasification catalyst to produce a combustible gas and an inorganic ash composed primarily of said inorganic compounds and a water soluble alkali metal vanadate and the inorganic ash is placed in a sufficient amount of water to dissolve the vanadate compound and then is recovered by conventional means.

Abstract: A process for the removal of metal poisons such as nickel, iron and/or vanadium from a hydrocarbon conversion catalyst which includes the step of contacting the catalyst with a reductive wash medium comprising an aqueous, preferably saturated, solution of SO.sub.2 to remove at least a portion of the metal poisons. The vanadium and nickel metals may be recovered from the resultant used wash solution for possible metallurgical use. The SO.sub.2 reductively washed catalyst may also be subjected to a subsequent oxidative wash such as hydrogen peroxide wash prior to its return to the hydrocarbon conversion process.

Abstract: Solid carbonaceous fossil fuels such as coal, lignite and peat are treated with an aqueous medium containing a novel catalyst to remove undesirable constituents and produce valuable products. The catalyst is prepared by steps including admixing a water soluble alkali metal silicate with an aqueous medium containing carefully controlled amounts of dissolved water soluble substances which are sources of calcium ion and magnesium ion, reacting the same to produce an aqueous colloidal suspension of the reaction product, admixing a micelle-forming surfactant with the aqueous medium, and agitating the aqueous medium containing the colloidal particles and surfactant to form catalyst-containing micelles. In one variant, particles of a fossil fuel containing metal values are treated with an aqueous medium in the presence of the catalyst, and thereafter the treated particles are separated from the aqueous medium and extracted with an aqueous leach solution in which the metal values are soluble.

Abstract: A process for the continuous leaching of ores and an apparatus for practicing this continuous leaching process are disclosed. According to this process, a plurality of unit layers composed of a pulverized uranium ore or other ore are continuously laminated while a minimum necessary amount of an acid, alkali or organic solvent (hereinafter referred to as "solvent") is uniformly sprinkled on the flat surfaces of these unit layers. In the state where the concentration of the solvent mixed into the ore is maintained at a high level, the heat generated by exothermic reaction caused by contact among the solvent, ore and water is effectively stored and used for thermally curing the ore. According to this process, the speed of extraction of the intended metal component can be increased, the leaching time shortened and the filtration characteristics improved, whereby a highly concentrated pregnant liquor can be recovered at a high efficiency.

Abstract: A method of extracting high purity columbium oxide, also known as niobium oxide, from barium-rich pyrochlore ores by treating the ore with a calcium salt such as calcium chloride, fusing the ore with caustic soda and a fluorine containing compound, and subsequently acid leaching the fused mass; and from calcium-rich pyrochlore ores by fusing the ore with caustic soda and a fluorine containing compound, and subsequently acid leaching the fused mass. The amount of fluorine containing compound used should contain anywhere from above 2% to about 10% fluorine content by weight relative to the ore.

Abstract: The present invention provides a method for recovering vanadium from ferruginous chloride solutions by liquid-liquid extraction (or liquid ion exchange). Such chloride solutions are obtained in the extraction of vanadium from vanadiferous residues arising from the chlorination of titaniferous ores and in the extraction of vanadium from vanadiferous minerals. These solutions contain chlorides of vanadium, aluminum, iron, manganese and chromium. The method comprises adding sulfate ions to the chloride solution and recovering the vanadium by liquid-liquid extraction. By adjusting the sulfate-additive in relation to the concentrations of vanadium, iron and chloride in the solution vanadium can be exhausted substantially free from iron.

Abstract: From roasted products of used catalysts from hydrotreatment desulfurization of petroleum, valuable molybdenum, vanadium, cobalt and nickel are recovered easily and a high percent recovery by means of a combination of simple chemical procedures and also inexpensive chemicals. The recovered metal components can be reused for preparing new catalysts and the like.

Abstract: A process for the recovery of vanadium from acid sulfate solutions such as those derived by sulfuric acid leaching of industrial residues such as spent hydrodesulfurization catalysts, fly ash and furnace bottom ash in which magnesium oxide, hydroxide or carbonate is used as the neutralizing agent.

Abstract: Titanium metal values may be recovered from a metal bearing source by subjecting the source to an oxidation step. The oxidized source is then divided, one portion being set to a reductive roast followed by leaching with hydrochloric acid. Thereafter, the remaining portion of the oxidized source is brought into contact with the leached solution whereby titanium dioxide is precipitated. The precipitated titanium dioxide is separated and recovered while the soluble metal values are treated for recovery thereof with a concurrent formation of hydrogen chloride, the latter being recycled back to the leaching zone.

Abstract: A process for recovering vanadium values from carbonaceous type vanadium ores, and vanadium scrap, such as vanadium contaminated spent catalyst, is disclosed which comprises roasting the vanadium containing material in air at a temperature less than about 600.degree. C to produce a material substantially devoid of organic matter, subjecting said roasted material to a further oxidizing roast in an oxygen atmosphere at a temperature of at least about 800.degree. C for a period sufficient to convert substantially all of the vanadium to the soluble form, leaching the calcine with a suitable dilute mineral acid or water at a pH of neutral to about 2 to recover vanadium values, precipitating vanadium values as iron vanadate from the leach solution with a soluble iron compound at a pH from neutral to about 1, and recovering ferrovanadium from the iron vanadate by a reduction vacuum smelting operation.

Abstract: Process for quantitatively converting non-ferrous metals chosen from the group consisting of copper, nickel, cobalt, vanadium, and manganese in an ore concentrate to soluble sulfates and simultaneously convert the ferrous values in the ore to insoluble oxides. The process comprises roasting finely divided ore particles at a temperature in excess of 650.degree. C. in the presence of a roaster gas comprising at least a stoichiometric amount of oxygen and at least 1% SO.sub.2. The roasting is performed in the presence of a sufficient amount of a mixture of salts to allow the formation of a liquid coating on the ore particles. In a preferred embodiment, the mixed salt which forms the liquid coating comprises Na.sub.2 SO.sub.4 and K.sub.2 SO.sub.4 with the ratio of sodium to potassium being between 1.0 and 2.0.

Abstract: A process for the separation of a low metals content organic material from an easily calcinable solid material, effected by treating a low-melting solid material, resulting from the refining of a hydrocarbon crude oil, with naphtha at an elevated temperature and pressure whereby the resulting solid material, after separation of the liquid organic material, is in condition to be readily calcinable.

Abstract: The present invention provides a method for recovering vanadium, niobium, tantalum and zirconium from vanadiferous residues arising from the chlorination of titaniferous ores. Such residues contain chlorides of these metals and/or titanium, aluminum, iron, chromium and manganese together with carbon and unreacted titaniferous ore. The method comprises first moistening these residues with water and then treating them with hot water for a sufficient period of time to extract substantially all the vanadium into solution which is separated from insoluble material comprising carbon and unreacted titaniferous ore together with substantially all the niobium, tantalum and zirconium.

Abstract: Soot produced in the combustion of fuel oil contains valuable metals, such as vanadium and nickel. The soot can be disposed of, and the valuable metals can be recovered, by leaching the soot with an aqueous solution of sulphuric acid, to extract part of the metal content from the soot, combusting the soot thus leached, and leaching the combustion residue with an aqueous solution of sulphuric acid, to extract an additional part of the metal content. The solution produced in this second leaching process is preferably returned to the leaching of the soot. Metals can be recovered in a way known per se from the solution produced in the leaching of the soot.

Abstract: Vanadium and molybdenum are recovered from a spent desulfurization catalyst containing the same by a process involving intimately admixing with comminuted catalyst an amount of a solid alkali metal carbonate, such as calcined sodium carbonate, sufficient to convert the vanadium and molybdenum present into water-soluble compounds, heating the mixture in the solid state in the presence of air at a temperature between about 650.degree. C and about 850.degree. C for a period of about 1 to 2 hours, and extracting the vanadium and molybdenum compounds with water.

Abstract: Method for extracting vanadium-values from vanadium-bearing iron ores and/or iron ore concentrates including mixing the iron ores and/or iron ore concentrates with a calcium containing material, roasting the mix in an oxidizing atmosphere at a temperature for a time to produce calcium vanadates, comminuting the roasted mix and leaching the comminuted roasted mix in an aqueous solution containing carbonate or bicarbonate compounds to produce vanadates which are readily soluble in the aqueous leaching solution and simultaneously producing substantially insoluble calcium carbonate or calcium bicarbonate which remains as part of the undissolved residue containing iron-values. The vanadate-rich aqueous leaching solution is separated from the undissolved residue containing iron-values and treated by known methods to recover the vanadium-values. The undissolved residue can be processed to recover the iron-values.