Abstract: A process for the production of alumina from aluminum-containing mineral ores, such as bauxite, comprising comminuting the aluminum-containing mineral ore, then reacting the comminuted mineral ore at an elevated temperature with an aqueous solution having at least 150 grams per liter of sodium bicarbonate which forms a solid reaction product containing dawsonite and impurities, and finally converting the dawsonite to alumina.

Abstract: The bayerite form of crystalline alumina, Al(OH).sub.3, contained within a macroporous ion exchange resin is converted to the gibbsite form of Al(OH).sub.3 by reaction with hot MgX.sub.2, where X is halide, followed by water-washing the MgX.sub.2 portion from the product, thereby causing the conversion of bayerite to the gibbsite form of crystalline Al(OH).sub.3. The gibbsite form may then be reacted with hot LiX solution, where X is anion, to form crystalline 2-layer LiX.2Al(OH).sub.3.nH.sub.2 O.

Abstract: A process for separating inorganic substances involving their abstraction from a mixture with near-supercritical inorganic fluids. One or more inorganic substances are abstracted and then separatively recovered by retrograde condensations. The process particularly is applicable with mixtures obtained from the chlorination of metalliferous ores and may be conjoined to many ancillary metal abstraction processes such as volatilizations, distillations or electrolyses.

Abstract: A method of processing naturally occurring kaolin clay wherein ion exchange resins are utilized to remove charged soluble impurities from the clay thereby eliminating the filtration step required in conventional clay beneficiation process. Further, by saturating the ion exchange resin utilized with a bleaching agent, ferric ions in the clay will be reduced to soluble ferrous ions and removed from the clay without the conventional acid leaching.

Abstract: A process for removing sulfur dioxide from effluent gas and for recovering amphoteric components such as alumina from solid inorganic combustion byproducts.

Abstract: A process of removing iron impurities from ores, particularly useful for removing stains of iron impurities adhered to silica sand particles, comprises grinding the ore, washing and desliming the ground ore to remove the major part of the clay-type binder, attrition-scrubbing the deslimed particles to release further amounts of binder therefrom, washing and desliming to remove said binder, drying and heating the ore particles, treating the hot particles with a chemical agent suitable to conver the iron impurities into water soluble iron compounds, attrition-scrubbing the hot suspension of chemically treated particles to release the stains of iron impurities, and washing with cold water and desliming to recover the purified ore particles.

Abstract: A process of purifying silica sand comprises grinding sandstone, washing and desliming the ground sandstone to remove the major part of the clay-type binder, attrition-scrubbing the deslimed sand particles to release further amounts of binder therefrom, washing and desliming to remove said binder, drying and heating the sand particles, treating the hot sand with sulfuric acid to convert the iron oxides, ferrosilicates and ferro-aluminous impurities into water soluble compounds, attrition-scrubbing the hot suspension of the chemically treated sand to release the strongly adhering stains of said impurities, washing with cold water and desliming, conditioning the sand suspension with fatty acids or petroleum sulfonate collectors, a polyalcohol frothing agent and, if necessary, a mineral acid to bring the pH to from 1.5 to 7.

Abstract: An improvement in the lime-sinter process for recovering alumina from pulverized coal fly ash is disclosed. The addition of from 2 to 10 weight percent carbon and sulfur to the fly ash-calcium carbonate mixture increase alumina recovery at lower sintering temperatures.

Abstract: A process for recovery of aluminum from clay comprising treating the crushed clay with water in the form of a fine mist, and in an amount sufficient to form compact surfaces on the particles without agglomeration thereof, and subsequently drying the misted clay to cause the particles to shrink and harden, and calcining and leaching with a mineral acid to extract aluminum from the clay.

Abstract: A high quality iron oxide concentrate, suitable as a feed for blast and electric reduction furnaces is recovered from pulverized coal fly ash. The magnetic portion of the fly ash is separated and treated with a hot strong alkali solution which dissolves most of the silica and alumina in the fly ash, leaving a solid residue and forming a precipitate which is an acid soluble salt of aluminosilicate hydrate. The residue and precipitate are then treated with a strong mineral acid to dissolve the precipitate leaving a solid residue containing at least 90 weight percent iron oxide.

Abstract: The invention relates to plant operations for increasing the cycle times of heat exchangers by the digestion of the aluminium oxide content of a slurry according to the Bayer technology, said slurry consisting of bauxite and sodium aluminate liquor, using an equipment in which the material is heated stepwise and in more parallel material streams, then the material streams are combined and further heated, or combined and kept at the same temperature, or after combination further heated and kept at the same temperature, characterized in that a part of the parallel material streams is slurry, another part of same is aqueous sodium hydroxide solution, preferably sodium aluminate liquor containing sodium hydroxide, or water, and the parallel material streams are exchanged in the heat exchangers in a cyclical manner.

Abstract: A process for the recovery of substantially all of the aluminum from aluminum bearing waste products which includes a method for the commercial production of alumina and compounds of alumina.

Abstract: Disclosed is a method for obtaining alumina from silicates by calcining a dry mixture of the silicate and an alkali metal or ammonium salt, such as the sulphate, bisulphate, sulphite, etc. and dissolving the reaction product in water or an aqueous alkali. Hydrated alumina is precipitated from the resulting solution and calcined to alumina.

Abstract: A process for the recovery of soluble alumina values from alumina-bearing ores comprising simultaneously contacting a stream containing an effective amount of a reducing agent such as SO.sub.2 and a stream containing an effective amount of an oxidizing agent such as Cl.sub.2 with an aqueous slurry of the alumina-bearing ores for a time sufficient to remove at least about 50 weight percent of the soluble alumina values from said ores is disclosed.

Abstract: Metals are extracted from mixtures of oxides or silicates by reacting the mixture at elevated temperature with a gaseous chlorinating agent comprising a mixture of water vapor and hydrogen chloride to selectively chlorinate the desired metal or metals.

Abstract: An improved method of extracting titanium from titaniferous materials by reaction with thionyl chloride to form titanium tetrachloride which is separated from the reaction products by volatilization or by extraction.

Abstract: When an alkali such as an alkali metal bicarbonate or carbonate is intimately mixed with bauxite or other alumina-containing raw material at an Al.sub.2 O.sub.3 /Na.sub.2 O molar ratio of from 1/1 to 1/3 and the mixture is molded into granules, then calcined and extracted with an aqueous medium, the alumina component can be recovered in a high yield in the form of an aqueous solution of an alkali metal aluminate. The alkali component is not substantially contained in the residue left after recovery of this aqueous solution.

Abstract: An improved method for recovering aluminum values from alkaline aluminosilicate raw material by sintering a comminuted aqueous mixture of the alkaline aluminosilicate material, limestone and soda solution wherein the alumino-silicate material is first comminuted with the soda solution to form a mixture with a fraction of particles larger than 0.08 mm greater than 20 percent by weight, mixing limestone with the mixture and comminuting until the fraction of particles larger than 0.08 mm is between 2 and 15 percent by weight.

Abstract: There is disclosed a method for the elimination of the chief impurities in aluminum dross tailings. The dross tailings, which are chiefly particles of aluminum oxide, are suspended in an aqueous slurry and the slurry is heated to a temperature from 185.degree.-225.degree. F. and maintained under liquification pressures and sufficient agitation to insure particle-to-particle attrition that removes an aluminum hydroxide coating which would otherwise inhibit the reaction. The reaction rate is accelerated by chemical and physical additives that can be optionally added to the slurry such as trace quantities of caustic, which serves as a source of hydroxyl ligands to increase the solubility of aluminum hydroxide and/or refractory particles such as ceramic spheres which increase the attrition. Other contaminants present in the dross tailings include aluminum nitride, which is decomposed to aluminum oxide and ammonia, and aluminum carbide which is decomposed to aluminum oxide and methane.

Abstract: The invention relates to a process for the disposal of bauxite processing wastes comprising the steps of:(a) filtering the bauxite muds in suspension coming from the washing decanter,(b) continuously washing the dehydrated filtration cake on the filter with hot water with recycling of the liquid phase containing the greater part of the soda into the basic chemical process of the bauxite treating plant.

Abstract: Particulate matter collected by an environmental air quality control device may be in part toxic in nature and thus not readily disposable. By separating the toxic portion of the particulate matter from a nontoxic portion, disposal of nontoxic portion may be more easily accomplished. This separation may be readily effected where the toxic portion is soluble and the nontoxic portion is insoluble, thus allowing the toxic soluble portion to be formed into a solution with a dissolving liquid. The nontoxic insoluble portion then may be filtered from the toxic solution, rinsed, dried and disposed of accordingly.

Abstract: Aluminum is recovered from solid rocket propellant containing a small amount of oxidizer by depolymerizing and dissolving propellant binder containing functional or hydrolyzable groups in a solution of sodium methoxide in an alcohol solvent optionally containing an aliphatic or aromatic hydrocarbon co-solvent and then filtering the solution to recover substantially all the aluminum in active form.

Abstract: An improved process for accelerating the digestion process in the Bayer alumina process is provided which promotes both the goethite-hematite conversion and a more perfect and quick dissolution of the diaspore. The above is achieved by carrying out the digestion in the process of 5-20% by weight calculated on the dry weight of the bauxite of a novel hydrogarnet catalyst.

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: The invention relates to a novel process for the selective recovery of the sodium content of red mud originating from alumina plants. According to the process of the invention red mud or a slurry thereof is admixed with a ferric sulfate solution, the resulting suspension is stirred intensively for 0.5 to 1 hour at 15 to 85.degree. C, thereafter, if necessary, the pH of the suspension is adjusted to 4.4 to 4.6 and the solid substance is removed from the suspension.Using the process of the invention the sodium oxide content of red mud can be reduced to below 1.5%.

Abstract: The red mud by-product of the Bayer process by which aluminum oxide is reed from bauxite as an aluminate, is digested with concentrated sulfuric acid or with sulfur trioxide gas to produce sulfates that can be leached out to the resulting mass with water. The solution is then heated at a pH of 1 to precipitate titanium oxide hydrate by hydrolysis. The remaining sulfates of the solution are then obtained in solid form by evaporation, or by precipitation with acetone, and the solid is then roasted to convert the aluminum and iron to the oxide. After leaching out the sodium sulfate with water, the aluminum and iron oxide are separated by the Bayer process, which works in this case even though x-ray diffusion patterns show that the aluminum oxide is mainly .alpha.Al.sub.2 O.sub.3.

Abstract: A process for alunite ore treatment which comprises roasting alunite in the presence of oxygen at a temperature of from 580.degree. to 620.degree. C. for 1 to 3 hours, decomposing the roasted alunite by exposure to reducing agents at a temperature of from 580.degree. to 620.degree. C., subjecting the reduced alunite to hydrochemical treatment by use of a sodium hydroxide solution of concentration from 100 to 150 g/lit in terms of Na.sub.2 O, decomposing the resultant aluminate liquor, with the aluminum hydroxide component precipitating out, and finally, washing and baking the aluminum hydroxide precipitate to obtain same as an end product. The invention provides a comprehensive method of treatment of alunite ores the associated rock whereof comprises silica in the form of opal and chalcedony earlier believed to be refractory to comprehensive treatment by alkaline methods.

Abstract: A fully integrated process is provided for the recovery of valuable components from waste materials generated in electrolytic aluminum reduction systems. The waste materials, such as spent pot linings, channel and trench cleanings, floor sweepings and spent alumina from offgas purifying dry scrubbers, are combined, then pyrohydrolyzed at elevated temperature. Fluoridic values, such as NaF and HF can be recovered from the offgas generated by pyrohydrolysis, while alumina and Na.sub.2 O values, or if desired, sodium aluminate, is reclaimed from the solid residue of pyrohydrolysis.The fluoridic values from the pyrohydrolysis offgas can be used for the manufacture of both electrolytes for aluminum reduction cells and also for the production of anhydrous HF. The alumina from the pyrohydrolysis residue can be reclaimed by a Bayer process-type leach with a caustic solution and the recovered high purity alumina utilized, for example, as reduction cell feed and/or for scrubbing reduction cell offgases.

Abstract: The invention relates to a process for the production of alumina from mineral component of solid fuels containing aluminum, silicon and iron oxides. The process comprises burning a mixture of a solid fuel with limestone in the following molar ratios of limestone to said oxides: CaO:SiO.sub.2 =2.0, CaO:Al.sub.2 O.sub.3 =1.3-1.8, CaO:Fe.sub.2 O.sub.3 =1.0, at 1700.degree.-1900.degree. C. As a result, a melt is obtained containing calcium compounds: 2CaO.SiO.sub.2, 12CaO.7Al.sub.2 O.sub.3, CaO.Al.sub.2 O.sub.3, CaO.Fe.sub.2 O.sub.3. The melt is cooled and leached with soda solutions for extracting alumina. The sludge remaining after the leaching is suitable for Portland cement production. The invention enables a considerable enlargement of the range of starting products for aluminum and cement industries due to the use of the mineral component of solid fuels, an about twofold reduction of capital investments in the alumina production and reduction of the fuel consumption by 30-40%.

Abstract: The invention is an improvement in the method for recovering aluminum values from alunite ore by roasting the ore to remove water, reducing the ore by roasting it in a reducing atmosphere to remove sulfate, optionally roasting the reduced ore in an oxidizing atmosphere to convert any sulfides formed in the second roast to oxides, leaching the calcined ore with water as a solvent to remove compounds of sulfur and alkali metals, recovering aluminum values as soluble aluminates from the residue from the leaching step by digesting it with at least one alkali metal hydroxide, removing contaminate silica from the resulting leach solution, and precipitating aluminum hydroxide from the solution, the improvement being the use of a two stage reduction of the dehydrated alunite ore, in which the ore is reduced by sulfur in the first stage, followed by a second stage reduction with another reducing agent such as hydrogen.

Abstract: The invention relates to an improved process for the production of alumina according to the Bayer technology, of bauxites containing goethite and especially of boehmitic or diasporic bauxites, for the acceleration of the digestion process, for the transformation of goethite into hematite, for the increase of alumina yield and for the reduction of the caustic soda losses, the essence of which consists in carrying out the digestion in the presence of 2-6% CaO and 0.2-2.0% Mg.sup.++, Fe.sup.++, Mn.sup.++ Co.sup.++ ions based on the weight of the dry bauxite or of compounds or ores containing these ions in the indicated quantities.

Abstract: Ceramic mold and core materials of magnesia doped alumina are removed from castings by a solution of either KOH or NaOH at elevated temperatures and pressures in an autoclave.

Abstract: An improvement in the process for recovering aluminum from alunite ore disclosed in U.S. Pat. Nos. 3,890,425 and 3,890,426, the improvement being in the recovery of potassium sulfate by crystallization from the leaching solution resulting from potassium hydroxide leaching of the roasted ore, the improvement consisting of adding potassium hydroxide to the concentrated leach liquor prior to crystallization to increase the concentration of the potassium ion so that increased recoveries of potassium sulfate are obtained at a given temperature over those obtained when this procedure is not used. By this procedure a yield is obtained at a temperature below that which is required to obtain the same yield when potassium hydroxide is not used so that the high temperatures formerly necessary to hold enough potassium sulfate in solution for an economic crystallization are avoided.

Abstract: The settling rate of caustic alkali-digested goethite-containing bauxite or laterite, or the like, is increased by carrying out the digestion in the presence of a reducing agent capable of reducing the trivalent iron component of the goethite to a lower valence so as to convert the goethite to hematite, magnetite, metallic iron, or combinations thereof, which enhance the settling rate of the digestion mass.

Abstract: An improvement in the process for the recovery of aluminum from alunite in which the alunite in particulate form is dehydrated, sulfur and alkali metal compounds removed from the dehydrated ore leaving a particulate residue containing aluminum values, the residue digested with at least one alkali metal hydroxide to convert the aluminum values to soluble aluminates, silicon removed from the soluble aluminate solution, and aluminum values precipitated from the aluminate solution, the improvement comprising: multiple stage digestion of the particulate residue accomplished by dividing the particulate residue into two fractions, digesting one fraction first and using the first stage liquor from the first digestion step to digest the remaining fraction. The fraction digested first may be the one having the smaller particle size, or the one having the larger particle size.

Abstract: The invention concerns a process for solubilizing alumina in minerals, rocks or industrial waste products, in which the starting material in finely divided form is mixed with lime in an amount 1 to 3 moles or more of lime (CaO or Ca(OH).sub.2) for each mole of alumina and optionally 1 mole for each mole of any silica present in the starting material, and at the same time or thereafter with water, the resulting mix is maintained under hydrothermal conditions until the alumina has become solubilized by reaction with the lime, and the product is if necessary comminuted to bring it to a form suitable for leaching out of the solubilized alumina.

Abstract: A process is disclosed for recovering the caustic and alumina values from high iron-containing Bayer red mud utilizing the so-called lime-soda-sinter process wherein a carbonaceous material such as coke is included in the sintering operation and leaching is carried out without any intermediate iron separation step.

Abstract: Back reactions of dissolved alumina from a high caustic-lime digest of anorthosite and other alumina-containing siliceous materials can be eliminated or mitigated by control of particle size of digestible material; and time and temperature of separation of the alumina-bearing liquid from the solid residues. In one embodiment the back reaction is further controlled by adjustment of the caustic concentration of the digest effluent.

Abstract: A process for recovering aluminum from alunite ore directed to providing a residue for the Bayer leach step substantially free of impurities so that a high A/C ratio Bayer leach liquor is produced, which comprises roasting the ore in particulate form to drive off water and sulfur as SO.sub.2 and to convert aluminum sulfate to alumina, leaching the residue containing aluminum values with water and filtering to remove potassium sulfate and other soluble sulfates, hot leaching the residue with sulfuric acid to convert the alumina therein to soluble aluminum sulfate followed by filtering to remove silicon dioxide and other solid impurities, crystallizing the aluminum sulfate to further remove impurities, heating the residue to convert the aluminum sulfate to alumina and drive off any remaining sulfur as SO.sub.2, and digesting the alumina calcine with sodium hydroxide under standard Bayer conditions at a high A/C ratio to provide a high A/C ratio solution from which a "sandy" aluminum hydroxide is precipitated.

Abstract: This invention relates to an improvement in the well known "Bayer" process. In particular, the invention describes a process for the recovery of gallium and alumina from bauxite including the steps of:A. dissolving the ore in caustic soda solution under pressure;B. precipitation of pure alumina from the remaining caustic soda solution by reduction of temperature and pressure;C. subjecting the resulting mother liquor from (b) to an elevated temperature of 60.degree. to 450.degree. C and a pressure of 2 to 100 atmos. in the presence of an oxygen-containing atmosphere; andD. cementation of the gallium remaining in solution by contact with metallic aluminium.Step (a) is preferably carried out at a pressure of 5 atmospheres and step (c) is carried out in the presence of an atmosphere consisting substantially of oxygen at a pressure within the range 20 to 50 atmospheres and a temperature within the range 150.degree. to 350.degree. C.

Abstract: This invention relates to a method for recovering aluminum hydroxide from alunite ore by roasting the ore to remove water of hydration, roasting it again in a reducing atmosphere to remove sulfate, roasting a third time in an oxidizing atmosphere to convert any sulfides formed in the second roast, leaching with a weak base, leaching with water to remove potassium and sulfate, extracting the aluminum content with a mixture of sodium hydroxide and potassium hydroxide, removing contaminant silica from the leach solution, and precipitating aluminum hydroxide by cooling and seeding the solution.

Abstract: The present invention provides for an improvement in the Bayer Aluminum manufacturing process wherein the digestion of goethite-containing bauxite is effected in higher yields, at lower temperatures and in a single step by carrying out said digestion in a wet caustic solution containing both calcium oxide and sodium chloride.

Abstract: A process for the obtention of alumina and phosphate values by the alkaline decomposition of silica-containing aluminum phosphate ores comprises reducing the ore to a particle size of from about 6 to 13 mm; calcining the ore at a temperature of from 500.degree. to 750.degree. C in order to remove water of crystallization and combined water; grinding the calcined ore to a particle size of from 20 to 60 mesh (U. S. Sieve); treating the calcined and ground ore with an aqueous solution having a concentration of from 20 to 30% by weight caustic alkali at an initial temperature of from 65.degree. to 75.degree. C; quickly filtering the hot suspension thus obtained to remove the solid silica and heavy metal oxides; adding a 50% caustic alkali solution to the filtrate in an amount sufficient to obtain a total concentration of from 10 to 15% by weight of free caustic alkali; cooling the alkaline liquor accompanied by an elutriation action in an elutriator to a temperature of from 5.degree. to 10.degree.

Abstract: An improved process is provided for the recovery of sodium aluminate crystallized from a digest of caustic and lime with high-silica aluminous materials. The digest solution is concentrated by evaporation and then seeded with Na.sub.2 Al.sub.2 O.sub.4.2.5H.sub.2 O crystals to crystallize alumina from the solution as Na.sub.2 Al.sub.2 O.sub.4.2.5H.sub.2 O. The crystals are then separated from the mother liquor solution by filtration or centrifugation. The crystals are then washed with a solution having a lower caustic content than the mother liquor and an alumina concentration of about 50 grams per liter to remove any mother liquor remaining on the crystals. The sodium aluminate crystals are used as a feed for a subsequent Bayer processing step.

Abstract: In a process for extracting alumina from alumina-containing ores by individually preheating a slurry of alumina-containing ores in alkali solution, and an alkali solution, and feeding the preheated slurry and the preheated alkali solution to a digester maintained at a temperature of about 200.degree. to about 300.degree. C, thereby extracting alumina from the alumina-containing ore. The alumina extraction is carried out without any formation of scales on the inside surface of the preheater with a considerably prolonged operating duration by preparing a slurry having a molar ratio of Na.sub.2 O/Al.sub.2 O.sub.

Abstract: An improvement in processes for recovering aluminum from alunite ore which processes include roasting the ore to remove water of hydration, removing sulfur and potassium compounds from the roasted ore by a procedure including a final leaching step resulting in a residue and a solution containing potassium sulfate, effecting partial recovery of potassium sulfate from the solution by crystallization with some potassium sulfate being bled off from the mother liquor, converting aluminum values in the residue to alkali metal aluminates by digesting the residue with alkali metal hydroxide including a substantial amount of sodium hydroxide, removing silicon from the alkali metal aluminates leaving a waste desilication product, recovering aluminum values from the desilicated aluminates by precipitation, circulating the mother liquor from the precipitation step to digestion as contaminated sodium hydroxide is bled off, the improvement which comprises enhancing the economics of the overall process by introducing therei

Abstract: A process for the extraction of gallium from sodium aluminate liquors comprises extracting gallium from aluminate liquors by cementation with the aid of a liquid gallium-aluminum alloy. Aluminate liquors produced in the Bayer process, prior to cementation, are freed from various impurities. To this end, the recycle aluminate liquor is cooled to a temperature at which soda crystallizes and vanadium is retained in the liquor, whereupon the crystallized precipitate is separated, while the residual liquor is mixed with the mother aluminate liquor in the ratio of 0.1-1 to 1-0.1. The resultant liquor is cooled down to ambient temperature, and the vanadium precipitate is separated. The process is a major step towards a simpler technique of gallium extraction from aluminate liquors both high and low in gallium. Also, the process permits extracting, directly from aluminate liquors, gallium in a higher degree of purity than can be obtained in the prior art.

Abstract: A method for processing alunite consisting in that alunite ore is treated with a solution of caustic alkalis at a maximum temperature of 60.degree.C, and a solid residue resulting from the above operation and containing largely potassium and sodium sulphates, is washed with hot water. As a result, potassium and sodium sulphates are dissolved in the wash water, and potassium sulphate is isolated by the action of a caustic-potash solution. The method enables losses of alkalis and aluminium during processing alunite ores containing active forms of silicon compounds to be much reduced, which compound when treating alunite ores with a solution of caustic alkalis, are liable to form insoluble aluminosilicates which are discarded into slime and thus lost together therewith when the latter is separated from the process solution.

Abstract: The specific feature of the present method is that in the process solution resulting in the processing of alunite with the object of producing alumina and potassium sulphate therefrom, an excess amount of sodium ions is maintained with respect to the potassium ions.The method is advantageous in that it ensures a higher yield of potassium sulphate and a lower contamination of the final products with respect to sodium and potassium ions.

Abstract: The invention provides novel water-soluble copolymers useful as flocculating agents, especially in flocculating the red mud formed during the Bayer process for the production of alumina from bauxite. The copolymers comprise anionic monomer units e.g. acrylic acid units in a mole percentage of less than 50% and acrylamide type units some of which are methylolated.