Abstract: The process of the invention is for the separate recovery of elemental sulfur and residual sulfides and metal salt solution from reaction slurries obtained from leaching of metal sulfides in ores and concentrates.

Abstract: Sulfidic minerals containing metal values such as copper, silver, nickel, cobalt, molybdenum, zinc, iron, or mixtures thereof are leached in two stages. In the second stage, preleached minerals are oxidized with nitrogen dioxide to enable the metal values to be solubilized in the aqueous acidic leach liquor in that stage. During the reaction, the nitrogen dioxide is reduced to nitric oxide. The nitric oxide is oxidized to nitrogen dioxide by oxygen. The acidic metal bearing liquor from the second stage flows to a first stage where it preleaches fresh minerals. The metal bearing liquor is delivered from the first stage to metal recovery while preleached minerals are delivered to the second stage.

Abstract: A process for recovering tungsten from tungsten bearing ores comprises producing a concentrate from the ore and leaching the concentrate at atmospheric pressure in a strong mineral acid solution, for example, a solution of sulfuric acid, hydrochloric acid or nitric acid within a temperature range of from 40.degree. to 90 Centigrade for from one to four hours in the presence of an inorganic complexing agent, and adding an ammonium salt compound for precipitating the tungsten. The precipitate is then dissolved in Ammonium Hydroxide and the tungsten recovered as Ammonium Paratungstate.

Abstract: Tungsten is extracted from hot springs tungsten ores by means of a process comprising (1) calcining the ore, (2) quenching the calcined ore in aqueous alkaline solution and (3) treating the resulting slurry at elevated temperature and pressure to extract the tungsten values from the ore.

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: A method for producing alkali metal chromates by double roasting chrome ores without the use of alkaline earths is disclosed. 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, in both roasts.

Abstract: Reducible pollutants can be detoxified by reduction and metals can be recred by reduction of the corresponding metal ions by bringing into contact a catalyst with the solution which is suitable for the electrochemical reduction of the ions in question, and mixing into the solution (or bubbling therethrough in the case of a gas) a reducing agent that has a redox potential in the redox system of the reducing agent and its oxidation product that is more negative than the redox potential of the substance to be reduced and its reduction product. The catalyst is a material that is suitable for use as an anode material at which hydrogen can be oxidized in a fuel cell. Such catalysts include finely divided platinum, activated carbon coated with platinum, tungsten carbide and activated carbon coated with tungsten carbide, particularly. Hydrogen is a good reducing agent for the purpose.

Abstract: A method for recovering nonferrous metal values from hydroxide sludge wastes containing same by first chlorinating the aqueous waste to oxidize the chromium therein, separating the insoluble components therefrom and treating the resulting Cr(VI) solution in a fixed bed anion exchanger to separate the Cr(VI) from the solution, separating the copper from the aqueous solution by liquid-liquid extraction, separating the zinc from the copper-free solution by liquid-liquid extraction, precipitating and separating the aluminum in the form of hydroxide from the zinc-free solution and then separating the nickel from the aluminum-free solution by liquid-liquid extraction, and recovering the nonferrous metals from the respective solutions and precipitates by conventional procedures.

Abstract: An energy efficient process is disclosed for the hydrometallurgical oxidation of sulfidic minerals containing copper, silver, nickel, cobalt, molybdenum, or zinc values. A high density slurry, e.g., 67% by weight solids, is prepared from a particulate sulfide mineral and water. Nitrogen dioxide and preferably also oxygen are added to the slurry to oxidize the sulfidic minerals and to produce solubilized cations and nitric oxide. The nitric oxide is oxidized to nitrogen dioxide, thereby regenerating the principal oxidant. If oxygen is added to the slurry along with NO.sub.2, then the regeneration occurs in-situ.

Abstract: In the recovery of chromium from a residue containing chromate and vanadate, by oxidative decomposition of a chromium and vanadium-containing ore in the presence of an alkali at temperatures of about 600 to 1200.degree. C., and leaching such residue with water, the improvement which comprises adding titanium dioxide to the residue and heating, whereby upon leaching the chromium enters the water while the vanadium is substantially left in the residue.

Abstract: A process for the recovery of copper, molybdenum, gold and elemental sulfur in tailings from hydrometallurgical processing of copper sulfide ores, the process comprising concentrating the tailings containing elemental sulfur and copper, gold and molybdenum to a small bulk volume by froth flotation to reject barren gangue including jarosite, if present, and other impurities, separating the liquids and solids in the float concentrate, leaching the resulting residue with a solvent for sulfur followed by liquid-solids separation and recovering elemental sulfur from the liquid, leaching the residue from the sulfur solvent leach with ferric chloride to selectively dissolve copper and iron therein followed by liquid-solids separation and recovering copper from the liquid or sending it back to the hydrometallurgical circuit, leaching the residue from the ferric chloride leach with cyanide to selectively solubilize gold followed by liquid-solids separation and recovering of solubilized gold from the liquid, recovering

Abstract: Sulfidic minerals containing metal values such as copper, silver, nickel, cobalt, molybdenum, zinc, iron, or mixtures thereof are oxidized with nitrogen dioxide to enable the metal values to be solubilized in an aqueous acidic leach liquor. In practicing the invention, the minerals are added to an aqueous acidic leach liquor and a nitrogen dioxide containing gas is sparged through the slurry to oxidize the metal values. During the reaction, the nitrogen dioxide is reduced to nitric oxide. The nitric oxide is oxidized to nitrogen dioxide by oxygen, either in-situ, or in a separate off-gas oxidizer.

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: A process for extracting non-ferrous metal values from an oxide ore. The process comprises leaching the ore with a solution containing at least one alkali metal chloride or alkaline earth chloride salt in the presence of an oxygen-containing gas at a temperature and pressure sufficient to solubilize the non-ferrous metal values into the solution of the metal chloride salt.

Abstract: In the disintegration of at least one chromium source selected from the group consisting of a SiO.sub.2 -containing chromite and a chromium-containing residue with an alkali compound at a temperature above about 800.degree. C in the presence of atmospheric oxygen and a lime-free diluent, followed by leaching of the mixture with at least one of water and/or a chromium (VI)-containing aqueous solution, the improvement which comprises including in the mixture to be disintegrated an aluminum compound and at least sufficient alkali to form alkali chromate and to convert the SiO.sub.2 into an alkali-aluminum silicate corresponding to the formula nMe.sub.2 O . mSiO.sub.2 . Al.sub.2 O.sub.3, wherein Me is at least one of sodium and potassium, 0.8 .ltoreq. n .ltoreq. 1.2 and 1.3 .ltoreq. m .ltoreq. 4.3.

Abstract: A process in which copper, nickel, cobalt and molybdenum are recovered by reducing comminuted raw manganese nodules with an aqueous solution containing cuprous ions. An improvement is disclosed in which copper is oxidized to provide a starting solution of cuprous ions for the process. In one important embodiment of the invention wet copper cement is added to a solution of carbon dioxide and ammonia and ground manganese nodules are then added to the mixture. As a result, a starting solution containing cuprous ions is produced. A major advantage gained from utilizing manganese nodules as an oxidizing agent is that the manganese nodule is itself reduced and its metal values are added to the reaction solution.

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: A process is disclosed for incinerating tannery waste solids containing organic material and chromium which comprises burning at least one ton per day of said waste in the combustion zone of an industrial furnace at a low temperature, preferably between about 800.degree. F. and 1200.degree. F., to convert at least a portion of the organic material to gases and the chromium to ash, removing the gases from the combustion zone and subjecting them to further oxidation, and removing the ash from the furnace. The waste solids include sludge separated from liquid waste, leather scrap, or preferably both. By controlling temperature, waste composition, or both, the chromium in the ash can be obtained in either trivalent or hexavalent form. The hexavalent chromium can be extracted with solvent for reuse in the tanning process. Trivalent chromium, with or without carbon, can be recovered as chromic oxide in an improved stable form for landfill, storage or shipment to a reprocessing center.

Abstract: A process for extracting metal values from sea nodules is provided in which nickel, cobalt and copper values are selectively extracted by leaching raw sea nodules in an aqueous ammoniacal medium in the presence of a reducing agent for tetravalent manganese and carbonate to precipitate the reduced manganese as manganous carbonate.

Abstract: A process is provided for extracting tungsten values from tungsten compositions. The process comprises treating a tri (alkaline earth metal) tungstate, especially tricalcium tungstate, at a temperature of preferably no greater than 50.degree. C. with a aqueous solution of hydrochloric and/or nitric acid, preferably having a concentration of no greater than 5 molar. The acid is supplied in excess of te stoichiometric amount required to convert the tungstate to tungstic acid and sufficient to maintain the thusly formed tungstic acid insoluble in the solution. The tungstic acid can then be separated from the solution and converted to soluble ammonium tungstate, which in turn can be converted into tungsten trioxide and finally into metallic tungsten. The tri (alkaline earth metal) tungstate starting material can be prepared from iron tungstate, manganese tungstate, and/or an alkaline earth metal tungstate or from ores or concentrates of these tungstates, by a high temperature treatment with calcium oxide.

Abstract: Copper, iron, and lead impurities are removed from molybdenum flotation concentrates by mixing the feed concentrates with a nonvolatile chloride salt, heating the mixture to a temperature of from about 200.degree. to 350.degree. C for a time sufficient to activate the lead impurities in the concentrates so that they can be leached therefrom during the subsequent leach step, and leaching copper, iron, and lead impurities from the heat-treated concentrates with a mildly oxidizing leach solution containing chloride ions and having a pH of no more than 4. Preferably, the mixing of the chloride salt and the feed concentrates is achieved by thoroughly mixing an aqueous solution of the salt with the feed concentrates.

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.

Abstract: A process is provided for preparing ammonium tungstate. In the process, a reduced calcium tungstate is treated in the presence of an oxidizing agent with an aqueous solution having at least ammonium cations and carbonate and/or bicarbonate anions, at a temperature of 10.degree. C to the boiling point of the solution. The reduced calcium tungstate reacts with the ammonium cations to form the ammonium tungstate which is soluble in the solution and with the anions to form a calcium compound which is insoluble in the solution. Oxygen and/or hydrogen peroxide are preferred oxidizing agents. The process is especially useful in separating tungsten values from scheelite ores or concentrates.

Abstract: A process is provided for treating tri (alkaline earth metals) tungstates with an aqueous solution containing cations selected from ammonium, sodium and potassium ions and mixtures thereof, and anions selected from hydroxide, carbonate, bicarbonate, and phosphate ions and mixtures thereof, to form a tungstate salt which is soluble in the solution and an alkaline earth metal compound which is insoluble in the solution. The tri (alkaline earth metal) tungstate can be prepared from iron tungstate, manganese tungstate, and/or an alkaline earth metal tungstate or from ores or concentrates of these tungstates, by a high temperature treatment with an alkaline earth metal donor compound, such as calcium oxide. A preferred soluble tungstate is ammonium tungstate, which can be further processed to yield tungsten trioxide and/or tungsten.

Abstract: A process of recovering molybdenum from waste products and particularly from spent catalyst based on active alumina and containing molybdenum compounds comprising mixing the spent catalyst with sodium carbonate powder, adding water and remixing to absorb the water in the catalyst particles, baking the mixture to convert the molybdenum present to sodium molybdate, treating the mixture at ambient temperature with carbon dioxide gas, treating the resultant mixture with hot water to dissolve the sodium molybdate, neutralizing and clarifying with concentrated nitric acid, and precipitating to produce molybdic acid high in purity that is suitable for the production of molybdenum compounds as well as for the recovery of the pure metal.

Abstract: A process of recovering molybdenum in the form of molybdic acid from waste products and particularly from spent catalysts containing a support based on gamma-alumina wherein the molybdenum is in the form of molybdenum oxide or molybdenum sulfide comprising treating the waste products with sodium carbonate and heating to convert the molybdenum present to sodium molybdate, and converting the sodium molybdate to molybdic acid by treatment with concentrated nitric acid to produce molybdic acid high in purity that is suitable for the production of molybdenum compounds as well as for the recovery of the pure metal.

Abstract: A process is disclosed for extracting nickel, copper, cobalt and molybdenum from a complex ore containing copper, nickel, cobalt, molybdenum, manganese and iron. The process features treatment of the ore with gaseous compound followed by leaching with an aqueous ammonia/ammonium salt solution into which is additionally introduced sulfite.

Abstract: Finely-divided metal oxides are prepared by the steps of (a) contacting a compound of a metal with a carbohydrate material to obtain an intimate mixture thereof, (b) igniting this mixture to oxidize the same and to insure conversion of substantially all of said metal compound to a fragile agglomerate of its metal oxide, and (c) pulverizing the product of step (b) to form a finely-divided metal oxide powder having a mean particle size below about 1.0 micron. Certain of the finely-divided metal oxide powders produced by this process have the useful property of sinterability at temperatures significantly lower than metal oxide powders heretofore readily available. The powders are useful in the preparation of high strength compacted shapes for use in high temperature and/or corrosive environment, in the preparation of refractory cements, catalysts, catalysts supports and the like.

Abstract: Manganiferous deep sea nodules containing non-ferrous metal values are selectively reduced to reduce manganic oxides to manganous oxide (MnO) and the non-ferrous metal values to the metallic state, and the selectively reduced nodules are then smelted to produce a molten metallic alloy containing the non-ferrous metal values and a slag containing most of the manganese. The molten alloy is blown with a free-oxygen-containing gas to eliminate most of the manganese, and the substantially manganese-free metal is then sulfided to produce a matte suitable for separation and recovery of the non-ferrous metal values. After sulfiding the matte can be blown with a free-oxygen-containing gas to lower the iron content thereof. Not all the iron is removed if it is advantageous to keep a high proportion of cobalt in the matte.

Abstract: A process for purifying an impure molybdenum oxide concentrate feed material to remove therefrom the predominant portion of contaminating metals present by autoclaving at an elevated temperature under an oxygen partial pressure of at least about 100 psi, a slurry of the particulated feed material in an aqueous acid solution containing a mineral acid for a period of time sufficient to convert the predominant portion of molybdenum compounds to molybdenum trioxide and to convert the contaminating metal compounds present to aqueous acid soluble compounds. The autoclaved slurry is thereafter filtered and the solids are subjected to an aqueous alkali hydroxide leach treatment to extract the molybdenum trioxide constituent therein in the form of alkali metal molybdate compounds, which subsequently are recovered from the leach liquor in the form of a high purity alkali metal molybdate product.

Abstract: A method for the complete dissolution of "hard to dissolve" mineral samples, such as lunar and geological samples, wherein milligram amounts of a sample in particulate form is successively mixed while heating with small amounts of hydrofluoric acid and a mixture of sulfuric acid and distilled, demineralized water. Heating of the resulting solution is continued until its volume is reduced to about 2 milliliters after which the solution is rapidly cooled to room temperature. After adding a small amount of distilled, demineralized water, it is heated while swirling to provide a crystal clear solution. When dissolving lunar or other samples containing beryllium and chromium, an amount of a solution of sodium hydroxide is added to the crystal clear solution that is sufficient to bring the pH of the solution to about 2.5. The method makes it possible to completely dissolve mineral samples rapidly and efficiently for subsequent accurate chemical analysis.

Abstract: A finely divided product containing Ni and Fe is dissolved in a sulfate-containing solvent in at least two stages and in the presence of an alkali metal and an oxidant for preciptating the Fe as alkali jarosite while Ni remains in solution which is subjected to an after-treatment. Similar processes can be used to separate cobalt and/or chromium from products containing either or both of these metals as well as iron.

Abstract: This invention relates to a froth flotation process for recovering scheelite from scheelite ores. This invention comprises adding a sulphonate collector or a mixture of a sulphonate collector and a fatty acid collector to a pulp containing the ores, selectively floating the scheelite from the ores and recovering the flotation concentrate thus obtained.

Abstract: Upgrading of titanium values in a slag such as Sorelslag by working up the lag such as by alkali salt roasting to render the slag leachable in a plurality of leaching stages to recover titania (and other) values of 94 to 97 percent purity useful in a sulphate or a chloride process for producing titanium dioxide.

Abstract: A metal recovery process in which copper, nickel, cobalt and molybdenum are recovered by reducing comminuted raw manganese nodules and leaching the reduced nodules with an aqueous ammoniacal solution to obtain a leach solution containing these metal values. In order to recover copper from leach solutions by techniques such as ion exchange extraction, it is desirable to oxidize the copper to the cupric state.In another embodiment, oxidation is required to bring about the solution of reduced metallic metal values of copper, nickel and cobalt or to convert lower valence ions of these metals to a more highly oxidized state. The present invention is an improvement in the foregoing metal recovery processes. In the present invention manganese nodules are used as the oxidizing agent to oxidize slurries containing pre-reduced manganese nodules which have lower valence ions of metals such as copper or the metal itself.

Abstract: A process in which copper, nickel, cobalt and molybdenum are recovered by direct leaching of comminuted raw manganese nodules after the nodules are reduced in a reduction circuit with an aqueous ammoniacal leach solution containing cuprous ions. An improvement is disclosed which results from recycling a portion of the metal values recovered back to the reduction circuit as a solid basic metal carbonate. The metal carbonate recycle enables the size of the reactors in the reduction circuit to be reduced. The recycle also increases the efficiency of the process by facilitating the solubilization of copper. Another aspect of the invention resides in the advantages of maintaining solubilized copper in amounts between 10 grams per liter and the solubility limit in the reduction circuit.

Abstract: A method is provided for separating chromium from lateritic ore. The ore which generally also contains nickel and cobalt along with other metal values is leached with a strong sulfuric acid solution of about 10 to 30 normal concentration at an acid to ore ratio of at least 3:1 by weight. The leaching is carried out at a temperature of at least 100.degree. C ranging as high as about 300.degree. C at above atmospheric pressure. An oxidant, such as manganese dioxide, is preferably added to oxidize the chromium to the hexavalent state, the manganese dioxide, or its equivalent, being advantageous in improving the chromium yield at the lower end of the leaching temperature range.

Abstract: In the recovery of molybdenum and rhenium values from sulfide ores, silica impurity is reduced to low levels by adding alumina to a carbonate fusion mix in an amount sufficient to combine with the silica present to form insoluble aluminum silicates, thus preventing its removal from the fusion mass during removal of soluble molybdenum and rhenium values by leaching, and thereby avoiding the necessity for conventional subsequent precipitation and filtration removal steps.

Abstract: Organic acids are added to ammoniacal leach liquors containing base metals such as copper, nickel and cobalt. Ammonia and carbon dioxide are then stripped from the leach liquor by heating the leach liquor sufficiently to drive off the ammonia and carbon dioxide. The resulting loss of ammonia and carbon dioxide causes the pH of the leach liquor to drop and enables the metal values to load onto the organic acid. Metal values are selectively stripped from the loaded organic acid.

Abstract: Metal values present as oxides, hydroxides or carbonates in ores or processed concentrates thereof are converted to the corresponding carbide by a solid state reaction with carbon, the carbide then is separated in substantially pure form and may be used directly as ferroalloy or may be converted to the metal.

Abstract: A simple, efficient and economical process for purifying molybdenum disulfide concentrates by contacting and digesting the molybdenum disulfide feed material with an aqueous acid solution containing a controlled combination of hydrofluoric acid and sulfuric acid in a manner to convert substantially all of the contaminating silica bearing minerals therein to aqueous soluble fluoride and sulfate compounds and any contaminating lead sulfide compounds to lead sulfate compounds, and thereafter washing, neutralizing and drying the purified molybdenum disulfide powder product. In accordance with a preferred practice, when the molybdenum disulfide feed material contains in excess of about 0.1% iron as an indication of pyrite concentration, the concentrate is calcined at an elevated temperature in a nonoxidizing atmosphere prior to the digestion step to effect a conversion of the pyrites to synthetic pyrrhotites, which are softer and less abrasive and are more acid soluble.

Abstract: A process in which copper, nickel, cobalt and molybdenum are recovered by direct leaching of comminuted raw manganese nodules with an aqueous ammoniacal leach solution containing cuprous ions. During the process cuprous ions are consumed and are oxidized to cupric ions. The cuprous ions are regenerated by reducing the cupric ions with a reducing gas. An improvement is disclosed which results from increasing the pressure of the reducing gas. This increased pressure facilitates maintaining a high cuprous ion concentration in each reaction vessel, by increasing the rate at which the cuprous ions are regenerated from the cupric ions without affecting the rate at which the metal values are recovered from the nodules, which in turn, increases the efficiency of each reactor thus enabling the size of reactors to be reduced.

Abstract: An improved hydrometallurgical method is provided for producing technical grade molybdic oxide from molybdenite concentrates. According to this method, the molybdenite concentrates are leached in an acid medium having a nitric acid concentration between about 25 gpl and about 50 gpl and an initial sulphuric acid concentration of nil to about 750 gpl, under oxygen pressure of about 100 - 250 psig and at a temperature above 115.degree. C so as to produce technical grade molybdic oxide having not more than 0.1% sulphur. Then a liquid-solid separation of the reaction mixture is effected and the obtained leach liquor is recycled back to the leaching stage optionally after partial neutralization with a basic reagent. The solid is washed and recovered as technical grade molybdic oxide.This invention relates to a novel method of producing hydrometallurgically technical grade molybdic oxide from molybdenite concentrates.

Abstract: A process in which copper, nickel, cobalt and molybdenum are recovered by direct leaching of comminuted raw manganese nodules with an aqueous ammoniacal leach solution containing cuprous ions. During the process cuprous ions reduce the nodules, are consumed, and are oxidized to cupric ions. The cuprous ions are regenerated by reducing the cupric ions with a reducing gas.

Abstract: Chrome saltcake has stable free flowing properties imparted to it by subjecting the sodium dichromate impurity present in chrome saltcake to reaction to form a product that is less susceptible to absorption of moisture than sodium dichromate.

Abstract: Process of extracting chromium from a chromium ore or concentrate by oxidation, which comprises suspending the chromium ore or concentrate in a bath of molten salts and introducing an oxygen-containing gas into the suspension in a sufficient amount and for a sufficient amount of time to oxidize chromium therein.

Abstract: Method for treating basic salts to preferentially extract copper without using a base to maintain the required pH. The liberation of unreacted hydrogen ions during the ion exchange reaction is eliminated by partially dissolving the basic salt mixture with an amount of acid that is equivalent to the non-copper content of the basic mixture. An amount of organic ion exchange extractant is selected so that the exchangeable hydrogen ion on the extractant is equivalent to or in excess of the amount of copper in the metal bearing liquor.

Abstract: Molybdenite or MoS.sub.2 materials, particularly finely divided flotation concentrates, are oxidized (roasted) to form molybdenum trioxide in a continuous composite fluidized bed containing non-elutriated refractory solids. A relatively high recycle ratio of oxidized calcine to feed is maintained for best results. The temperature of the circulated oxidized solids is maintained high to avoid sticking and deposition problems. High throughputs and high conversions have been achieved, with the product having a low sulfur content.

Abstract: An improved method of making finely divided, dry metal halides and sulfides, such as chromium chloride and chromium sulfide which are suitable for use as lubricants and wear-proof and corrosion-proof agents for metals.