Abstract: A process for the selective separation of ferric iron from an aluminum fluoride aqueous solution containing ferric iron is effected by contacting said solution with an organic extractant phase consisting essentially of a mixture of a mono (higher alkyl-substituted phenyl) phosphoric acid and a di(higher alkyl-substituted phenyl) phosphoric acid dissolved in an inert diluent to thereby transfer the ferric iron to said organic extractant phase. The efficiency of the process is further improved by adjusting the aluminum fluoride aqueous feed solution to a temperature in the range of about 140.degree. F. to about 175.degree. F. prior to contacting it with the organic extractant phase, maintaining the temperature within this range throughout the ferric iron extraction stage or stages, then heating the resulting iron-depleted aqueous raffinate to a temperature higher than 195.degree. F., and then crystallizing aluminum fluoride trihydrate out of the raffinate at this higher temperature.

Abstract: A process for the production of alumina from siliceous minerals containing substantial quantities of combined aluminium and calcium comprises the steps of treating the finely divided mineral with a hot acid liquor containing chloride, fluoride and calcium ions to extract alumina values from the mineral; recovering aluminium chloride from the liquid extract; recycling one fraction of the spent extract to the mineral extraction stage; and treating another fraction of the spent extract to regenerate hydrogen chloride gas for re-use in the process.

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: 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: A method of obtaining alumina of high purity from aluminous mineral containing impurities in which the mineral is attacked with a sulphuric acid liquor followed by separation of a liquid phase from the resulting solid residue comprising(1) mixing the liquid phase with a liquor containing HCl and H.sub.2 SO.sub.4 at elevated temperature,(2) cooling the mixture with the precipitation of hydrated aluminum chlorosulphate having the formula AlSO.sub.4 Cl.6- 7H.sub. 2 O,(3) separating the precipitate from the remaining liquor which contains the major part of the impurities in solution,(4) suspending the separated precipitate in a hydrochloric acid liquor,(5) chlorinating the suspension by introduction of gaseous HCl with precipitation of AlCl.sub.3.6H.sub. 2 O,(6) separating the precipitated AlCl.sub.3.6H.sub. 2 O, and(7) pyrolizing the separated precipitate to produce alumina of high purity and gaseous HCl.

Abstract: The invention is a method for working-up shale while recovering metals therefrom and the sulphur content thereof. The method comprises crushing the shale and leaching and roasting the shale. The sulphur content is oxidized and converted into sulphuric acid, concentrated sulphur dioxide or sulphur. The leaching operation is effected with sulphuric acid. The leached metals are recovered in a manner known per se and the residual solution is passed to the roasting stage.

Abstract: A process for the extraction of alumina from aluminum-containing silicates is disclosed. The process comprises acid leaching of the raw material, iron extraction, precipitation of the aluminum fraction as the aluminum chloride hexahydrate, removal of sodium chloride and calcination to alumina. The process can be made continuous with substantial regeneration and recycling of process components.

Abstract: A process is described for the recovery of gallium from scrap materials in which the gallium occurs as gallium compounds containing at least one element selected from the group consisting of aluminum, antimony, arsenic and phosphorus. The process comprises the steps of leaching said gallium compounds with an oxidizing agent selected from nitric acid and a combination of nitric acid and hydrogen peroxide to form a gallium-containing leach solution, forming a gallate solution from said gallium-containing solution, and recovering gallium from said gallate solution. The leach solution can be treated with a calcium compound chosen from the group consisting of lime and calcium hydroxide for precipitation of calcium arsenate and calcium phosphate. An alkaline material such as sodium hydroxide may then be added to said leach solution in an amount sufficient to raise the pH to a value of at least 11 to form gallate solution. Gallium metal preferably is recovered from said gallate solution by electrolysis.

Abstract: Alumina monohydrate is produced by leaching calcined clay and subjecting the leach liquor to pressure hydrolysis wherein the vapor and heat resulting from the pressure hydrolysis are directly utilized for leaching of the calcined clay. The aluminum monohydrate may be roasted to yield alumina.

Abstract: Aluminum may be recovered from various raw materials including kaolinite, alunite, coal ash and slag, and both raw and spent oil shale, by contacting such materials with an aqueous solution of hydrofluoric acid, followed by removal of the insoluble residues remaining suspended in solution and the precipitation of hydrated aluminum hydroxide from the clear solution by basification with an alkaline agent.

Abstract: In a coal gasification operation or similar process carried out in the presence of an alkali metal-containing catalyst wherein spent solids containing ash and alkali metal catalyst residues are produced, alkali metal constituents are recovered from the spent solids by first removing magnetic constituents from the solids, contacting the solid particles from which magnetic constituents have been separated with an acid solution to extract alkali metal constituents from the solids and produce a spent acid solution enriched in alkali metal salts, raising the pH of the enriched solution sufficiently to precipitate aluminum from the solution as aluminum hydroxide, heating the remaining solution to precipitate silicon compounds, and recovering an enriched alkali metal solution from which aluminum and silicon compounds have been removed.

Abstract: A method for dissolving clay is disclosed which comprises contacting the clay, in alteration, with separate slugs of a hydrogen ion-containing chemical and a fluoride ion-containing chemical. The hydrogen ions and fluoride ions react on the surface of the clay to produce hydrofluoric acid to dissolve the clay. The method is particularly valuable in dissolving the clay in a mixture of sand and clay without dissolving the sand. This finds immediate value in the practice of acid treating subterranean sandstone formations to increase permeability or to restore permeability damaged by clay.

Abstract: An apparatus for the production of pure alumina from alumina and silicate containing raw materials comprising means to feed said raw material into the top of an acid resistant leaching tower; means to continuously feed a leaching liquor containing hydrochloric acid into the bottom of said leaching tower, means to continuously flow said leaching liquor upward through said raw material to leach out the alumina as a solution of aluminum chloride, means to withdraw said solution enriched in aluminum chloride toward the top of said tower zone; means to withdraw said raw material solid residue from the bottom of said tower zone to convey said solid residue from said leaching tower into a separation zone at a level higher than the level of said leaching tower; and means to separate said solid residue from said carrier liquid in said separation zone.

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: Alumina monohydrate is produced by treating aluminum nitrate solution at a temperature of about 250.degree. to 350.degree. C and a pressure of about 500 to 2500 psig.

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: Hexagonal plate crystals of aluminum sulfate are produced in chemically pure form by a process which comprises cooling a heated saturated solution of chemically impure aluminum sulfate acidified with sulfuric acid to precipitate crystals of aluminum sulfate, heating the slurry of the cooled solution containing the precipitated aluminum sulfate crystals to a predetermined temperature wherein the temperature is maintained for a time sufficient to dissolve a portion of the crystals in the solution, cooling the heated slurry to precipitate aluminum sulfate crystals, and separating the precipitated crystals from the slurry.

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: The method comprises the steps of crushing of the ore, neutralization by a mixture of water and sulphuric acid, introduction of a controlled quantity of sulphur dioxide gas at a pH value between 1.5 and 4 for promoting dissolution of nickel, copper and a desired quantity of manganese, leaching of the ore with sulphuric acid at a pH value between 1 and 3 for selectively dissolving the nickel and copper, separation of the solid and liquid phases, and separation of the metals contained in the liquid phase.

Abstract: Metal values are extracted from manganiferous ocean floor nodule ore by treating the ore with hydrochloric acid, thereby producing chlorine and a starting pulp containing a solution of the metal chlorides and a solid residue. The starting pulp is subjected to at least two subsequent acidifications with HCl, each acidification being followed by addition of fresh ore, thereby producing chlorine and a final pulp containing a concentrated solution of metal chlorides and a solid residue. The solid residue is separated from the concentrated solution and substantially all the metal values, except manganese and alkali and alkaline earth metals, are separated from the solution. The manganese is separated from the solution by treatment with chlorine, at least the major portion of which was produced in the preceding leaching steps, while maintaining the solution at a pH of between about 3 and 7 by addition of a neutralizing agent such as MgO or Mg(OH).sub.2 whereby the manganese is precipitated in the form of MnO.sub.

Abstract: Bauxite waste red mud is treated with hydrochloric acid to dissolve only the sodium content. The treated material is mixed with kaolinitic clay and formed into construction bricks.

Abstract: A method for preparing a coating grade kaolin clay from a crude clay including discoloring iron contaminants in the form of iron pyrites. The clay is roasted in an oxidizing atmosphere to convert at least a portion of the sulfurous contaminants to a form exhibiting increased magnetic susceptibility and increased solubility in chemical leachants. Thereafter, the clay is formed into an aqueous slurry and subjected to a magnetic field to remove at least part of the converted components, and then subjected to conventional leaching and filtering operations.

Abstract: An aluminum-containing ore such as a kaolin or montmorillonite clay is treated with a fluorine acid such as HF or H.sub.2 SiF.sub.6 to produce aluminum fluoride (AlF.sub.3) which is recovered from the liquid phase of the reaction mixture by crystallization as AlF.sub.3 . 3H.sub.2 O crystals which are then dried and dehydrated to yield AlF.sub.3. The crystallization mother liquor is recycled to the process to recover its AlF.sub.3 values. The AlF.sub.3 . 3H.sub.2 O crystals and separated solid phase of the reaction mixture are washed to recover AlF.sub.3 values and the wash streams are recycled to the process. To produce alumina, the AlF.sub.3 is pyrohydrolyzed to Al.sub.2 O.sub.3 and HF. The HF is absorbed in the crystallization mother liquor and recycled with the mother liquor to the ore treatment step. All or a part of fluorine acid requirements can also be supplied from any suitable source such as, for example, a wet process phosphoric acid facility which is a plentiful source of inexpensive fluorine.

Abstract: A process for the extraction and recovery of aluminum from aluminum-containing raw materials by contacting said raw materials with fruit juices and complexing organic acids.

Abstract: In water treatment using alum and yielding a sludge containing aluminum hydroxide, alum is recovered by acidulating the sludge with sulphuric acid, conditioning the sludge with an inert additive for facilitating filtering, and supplying the conditioned sludge to a filter press. Alum in the filtrate is reused and make-up alum added as required. Periodically the cake in the filter press is neutralized with lime and disposed of. When the recovered alum becomes unsuitable for further use, the system is convertible to a sludge dewatering system in which acid is discontinued and lime added with the inert additive to condition the sludge for the filter press, the filtrate is returned to the water treatment system, and make-up alum is discontinued until all the stored recovered alum has been used up. New alum is then introduced and the sludge dewatering continued until the recovered alum has passed through the system and its coagulant product eliminated, the cake in the filter press being dumped as required.

Abstract: A process for the production of pure alumina from alumina and silicate containing raw materials comprising feeding said raw material into the top of an acid resistant leaching tower; continuously feeding a leaching liquor containing hydrochloric acid into the bottom of said leaching tower, continuously flowing said leaching liquor upward through said raw material to leach out the alumina as a solution of aluminum chloride, withdrawing said solution enriched in aluminum chloride toward the top of said tower zone; withdrawing said raw material solid residue from the bottom of said tower zone to convey said solid residue from said leaching tower into a separation zone at a level higher than the level of said leaching tower; and separating said solid residue from said carrier liquid in said separation zone.Apparatus for producing alumina according to this method includes the corresponding means.