Abstract: A process for recovering alumina values from a first liquor having an initial concentration of aluminate ions and hydroxyl ions in solution is described. The first liquor is treated with a hydroxide of a metal other than aluminium to form an aluminium-bearing layered double hydroxide and produce a treated stream of first liquor, the treated stream of first liquor having a final concentration of aluminate ions less than the initial concentration of aluminate ions. The aluminium-bearing layered double hydroxide is separated from the treated stream of first liquor. Thereafter the clarified treated stream of first liquor is returned to a first location within an alumina refinery. The separated aluminium-bearing layered double hydroxide is contacted with a solution containing carbonate ions to form a slurry comprising an insoluble salt of the metal other than aluminium and a second liquor comprising aluminate ions released from the aluminium-bearing layered double hydroxide.

Abstract: A method is disclosed for removing heavy metals from a solution of waste or effluent containing chelating agents such as ethylenediamine tetraacetic acid (EDTA), 1,2-cyclohexanediamine tetraacetic acid(CDTA), and citric acid(Citrate), comprising: acidifying the solution with nitric acid, and oxidization of the acidified solution under controlled pressure and temperature. Upon oxidation, the heavy metal chelate (EDTA-m, CDTA-m or Citrate-m) is decomplexed, and heavy metal ions are liberated and can be precipitated using a conventional precipitation method such as by treatment with lime and a flocculent.

Abstract: Disclosed is a process for removing acids in a system in which aromatic hydrocarbons are separated from a mixture with aliphatic hydrocarbons. The aromatic hydrocarbons are extracted from the mixture using an extracting solvent. The aromatic hydrocarbons are stripped from the extracting solvent with steam and the steam is condensed to form water which is separated from the aromatic hydrocarbons. The separated water is passed through a basic anion exchange column and is then heated to produce the steam.

Abstract: An industrial waste management facility (IWMF) for disposing of spent potlining includes a co-current gas-fired rotary kiln for containing a molten pool of spent potlining throughout the entire length of the rotary kiln from the inlet to the outlet, an ash quencher and cooler for receiving molten residue from the discharge end of the rotary kiln, a secondary combustion chamber, and a down-draft transition chamber for channeling discharge gases from the rotary kiln to the secondary combustion chamber. Pneumatic injection slingers feed and distribute spent potlining into the inlet end of the rotary kiln. A discharge dam provides a predetermined average depth of molten bath material in the rotary kiln over its entire length. A blended ratio of comminuted materials injected through the pneumatic injection slinger feeder is adjusted and controlled in response to signals received from a radiative optical kiln bath temperature measurement system.

Abstract: An industrial waste management facility (IWMF) for disposing of spent potlining includes a co-current gas-fired rotary kiln for containing a molten pool of spent potlining throughout the entire length of the rotary kiln from the inlet to the outlet, an ash quencher and cooler for receiving molten residue from the discharge end of the rotary kiln, a secondary combustion chamber, and a down-draft transition chamber for channeling discharge gases from the rotary kiln to the secondary combustion chamber. Pneumatic injection slingers feed and distribute spent potlining into the inlet end of the rotary kiln. A discharge dam provides a predetermined average depth of molten bath material in the rotary kiln over its entire length. A blended ratio of comminuted materials injected through the pneumatic injection slinger feeder is adjusted and controlled in response to signals received from a radiative optical kiln bath temperature measurement system.

Abstract: A method of treating Bayer process red mud slurries to improve or facilitate the handling thereof, comprising adding to such a slurry a minor porportion of humic acids or humates effective to reduce the viscosity of the slurry.

Abstract: A novel process for the recovery of alumina and potassium sulfate from alunite is provided comprising leaching the alunite with potassium hydroxide to which no sodium materials have been added, said leach solution being saturated with potassium sulfate. Aluminum values are solubilized into the leachate, and potassium and sulfur values are rendered soluble, but remain in the residue. The leachate is desilicated if necessary, preferably with lime, and aluminum trihydroxide is precipitated therefrom, followed by calcining to alumina product. The residue is leached to solubilize potassium sulfate in a secondary leach and the potassium sulfate product crystallized therefrom. Potassium hydroxide is regenerated from a portion of the potassium sulfate secondary leachate by several methods.Novel procedures for regenerating alkali metal hydroxides from the corresponding sulfates are also provided including routes involving formates and carbonates as intermediates and pyrohydrolysis.

Abstract: A process for cleaning lime having undesirable levels of contaminants, particularly manganese oxide, is disclosed. The process includes leaching the contaminants from the lime with an aqueous means, preferably spent Bayer liquor, to form a slurry containing said impurities and cleaned lime. The cleaned lime is then removed from the slurry containing the contaminants.

Abstract: The invention relates to a process for deironing red mud and bauxite and for the preparation of a raw material for alumina industry and of iron pentacarbonyl which comprises(a) activating the red mud or bauxite starting material at 150.degree.-800.degree. C. under a pressure of 0.1-100 bars in a reducing gas stream in the presence of one or more promoter(s) and thereafter(b) carbonylating at 50.degree.-300.degree. C. under a pressure of 25-300 bars with carbon monoxide or a gas containing carbon monoxide and removing the iron pentacarbonyl formed from the system.The advantage of the present invention is that it provides a process for the effective removal of the iron content of red mud or bauxite and moreover it enables the utilization of the removed iron in the valuable form of iron pentacarbonyl which is suitable for use in iron metallurgy.

Abstract: An annular groove formed on the inner surface of the porous sheet of an acoustical aircraft or jet engine liner spaced from the front edge and adjacent to the adhesive bonding material serves to prevent dislodgement of the entire porous sheet upon an impending peeling of the porous sheet. The groove also serves as a circuitous path for cracks propagating upstream from a fault manifested downstream therefrom.

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 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 first 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: Red mud slurries can be solidified by adding thereto certain fatty substituted quaternary ammonium salts.

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: 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: 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: A continuous process for the production by electrodialysis of monobasic potassium phosphate from phosphoric acid produced by the wet process and potassium sulfate produced as a by-product in processes for the recovery of aluminum from alunite.

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 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: A process for the production of monobasic potassium phosphate from wet process phosphoric acid and potassium sulfate by ion exchange. The application of the process is the production of monobasic potassium phosphate by ion exchange from wet phosphoric acid produced by the reaction of sulfuric acid on apatite rock and by-product potassium sulfate from processes for the recovery of aluminum from alunite.

Abstract: A method for dehydrating alunite ore prior to further processing to recover metals therefrom, comprising exposing the ore in particulate form to burning coal as the heat supply in a fluidized bed fluidized with an oxygen containing gas. The invention is illustrated by the removal of water from alunite ore prior to further processing the ore to recover aluminum.

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 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.