Abstract: As population density increases, the transportation of hazardous chemicals, including acids and disinfectants, lead to an increased incidence of spills while the consequences of spills become more serious. While solutions of halide acids, hypohalites and halites are safer disinfectants for transportation, handling, storage and use than traditional gaseous chlorine, the manufacturing cost of these disinfectants has here-to-fore limited their use. Economical processes are presented for the manufacture of O2, halogen oxides, halide acids, hypohalites, and halates; as well as polynucleate metal compounds, metal hydroxides and calcium sulfate hydrate (gypsum). The instant invention presents methods and processes that incorporate the use of sulfur. This is while environmental regulators, such as the US EPA, require an increased removal of sulfur from hydrocarbon fuels, thereby creating an abundance of sulfur, such that the refining industry is in need of a way to dispose of said abundance of sulfur.

Abstract: A mass of solid aluminium carbide containing product is produced by injecting particulate alumina into a bath (30) of molten aluminium metal; and injecting carbonaceous material, consisting of, containing or yielding carbon, into the bath (30). The bath (30) of molten aluminium metal is maintained at a superheated temperature to heat and react carbon with molten aluminium to produce solid aluminium carbide which mixes with alumina to form a mass (36) containing entrapped gas and entrapped molten aluminium metal and having a bulk or apparent density less than aluminium. The mass is allowed to accumulate as a mass of solid aluminium carbide containing product on the upper surface of the bath. The carbonaceous material is a hydrocarbon material or is produced by pyrolysis, decomposition or cracking of a hydrocarbon material.

Abstract: A carbothermic process for producing an aluminium carbide containing mass by injecting carbon and alumina into molten aluminium superheated above 1400° C. The carbon reacts with molten aluminium to produce an aluminium carbide and alumina mass. The mass can be heated in the range of 1700° C. to 2000° C. to produce aluminium metal and carbon monoxide.

Abstract: A process for the removal and causticisation of sodium oxalate and/or sodium sulphate from a Bayer process liquor containing sodium carbonate and one or both of sodium oxalate and sodium sulphate in an alumina refinery is described. The process is based on the observation that to efficiently causticise sodium oxalate solutions, it is first necessary to remove the aluminate ion from solution, optionally with recovery of the aluminate ion in some later step. This is effected by removing aluminate ions from the Bayer liquor through the formation of a carbonate bearing hydrocalumite and/or sulpha-bearing hydrocalumite. The liquor may then be treated with sufficient lime to remove and causticise any residual carbonate ions and some or all of the oxalate ions present so that any reacted lime solids thus formed can be separated and safely disposed of.

Abstract: The invention relates to the production of calcium compounds containing water of crystallization by means of a chemical reaction between an aqueous alkaline sodium aluminate solution and solid or dissolved or suspended calcium (hydr)-oxide in the presence of carbon dioxide or carbonate; and to the use of these compounds. The resulting precipitate is separated by sedimentation, dehydration, drying and/or clacination and/or grinding or suspending the resulting filter cake and reacted with at least one mineral acid and/or at least one salt of the same. The resulting precipitate, which contains water of crystallization, is separated by sedimentation, dehydration, drying and/or grinding.

Abstract: The present disclosure relates to a method for removing anions such as nitrate ion, sulfate ion, chloride ion, and phosphate ion existing in underground water, surface water or waste water. The method involves adding alumina cement and a calcium compound to the water containing the anion followed by applying an electric field thereto, thereby forming a chemical precipitate which is an insoluble complex salt. The disclosure also relates to a continuous process for removing the anion by continuously performing the above method for removing anions.

Abstract: Processes for treating iron containing waste streams are provided. According to these processes, metal-containing compounds, particularly iron oxides are produced. These methods may, for example, be used in the processing of the waste streams from the chlorination of titanium-bearing raw materials and involve the use of certain combinations of neutralization and precipitation steps.

Abstract: A process for the removal and causticisation of sodium oxalate and/or sodium sulphate from a Bayer process liquor containing sodium carbonate and one or both of sodium oxalate and sodium sulphate in an alumina refinery is described. The process is based on the observation that to efficiently causticise sodium oxalate solutions, it is first necessary to remove the aluminate ion from solution, optionally with recovery of the aluminate ion in some later step. This is effected by removing aluminate ions from the Bayer liquor through the formation of a carbonate-bearing hydrocalumite and/or sulphate-hearing hydrocalumite. The liquor may then be treated with sufficient lime to remove and causticise any residual carbonate ions and some or all of the oxalate ions present so that any reacted lime solids thus formed can be separated and safely disposed of.

Abstract: An improved process for the causticisation of Bayer liquors in an alumina refinery includes a first step of reacting lime with aluminate ions in a Bayer liquor within a primary reactor operated at low to moderate temperature to form a hydrocalumite species and hydroxyl ions. In a second step, the hydrocalumite species is heated in contact with a Bayer liquor, which either includes or is a different liquor than the Bayer liquor of the first step, under controlled conditions to cause the hydrocalumite species to react with the liquor to form calcium carbonate, aluminate ions and hydroxyl ions. The principal advantages of the improved process include very high lime utilisation efficiencies (in excess of 90%) and a substantially increased C/S ratio (in excess of 0.955), allowing higher plant caustic concentrations and improved productivity. The loss of alumina due to the formation of unwanted calcium aluminate species is also greatly reduced.

Abstract: This invention relates to a process for removing sulphates and calcium from a water stream which includes the steps of: combining the water stream and an amount of amorphous aluminum trihydroxide (Al(OH)3); allowing the formation of ettringite (3CaO.Al2O3.3CaSO4.31/32H2O) as a precipitate; and removing the precipitated ettringite from the water stream.

Abstract: A method for the processing of fly ash scrubber sludge or the like is provided. The method yields unique products, including a usable calcium silicate material and a high purity alumina material. The process involves a plurality of stages including a first magnetic separation in an acid leach. During the acid leach, valuable mineral components are converted into soluble sulfates. The leach residue, containing calcium materials, is extracted with ammonia solution to yield a desirable calcium silicate product. The leach liquor is treated in a preferred manner to precipitate relatively acid free aluminum sulfate. The aluminum sulfate is then converted into a desirable alumina product.

Abstract: A process for the production of large boehmite crystal aggregates, useful for soft polishing applications is provided herein. A caustic aluminate liquor is contacted with an oxygen-containing gas at elevated temperatures and pressures in the presence of about 1-50 mg/L of copper ions. The liquor is oxidized until a molar ratio of Na.sub.2 O.sub.free to Al.sub.2 O.sub.3 of less than or equal to 1 is achieved, and the oxidized liquor is cooled under quiescent conditions of little or no agitation which causes the crystallization and precipitation or novel large boehmite particles.

Abstract: Disclosed is a method for producing hydrotalcite in high yield including reacting activated magnesia with an aqueous solution containing aluminate, carbonate, and hydroxyl ions. The method further includes a first step of heating magnesium carbonate or magnesium hydroxide to a temperature between about 500.degree.-900.degree. C. to form activated magnesia or magnesium oxide. The method is suited to producing synthetic hydrotalcite from industrial Bayer liquor.

Abstract: A process for treating dry, particulate alumina for use in preparing alumina slurries which are resistant to gellation in which the particulate alumina is contacted with a carbon dioxide rich gaseous medium for a suitable time.

Abstract: A method for extracting oxygen from a fluid environment, which comprises the steps of (1) contacting a first fluid environment containing oxygen with a first surface of a first oxygen permeable membrane having a first and a second surface, wherein the membrane separates the environment from an interior space of a closed container, (2) transporting a carrier fluid into contact with the second surface of the membrane, wherein the carrier fluid is confined in the closed container and the carrier fluid contains a binding-state oxygen carrier, whereby oxygen which diffuses through the membrane binds to the carrier to give a bound oxygen complex, (3) transporting the carrier fluid containing the bound oxygen complex to a first electrode compartment of an electrochemical cell which forms a second portion of the closed container, (4) electrochemically modifying the binding-state oxygen carrier to an oxidation state having less binding affinity for oxygen, thereby releasing free oxygen into the carrier fluid and produ

Abstract: Particulate alumina-base catalysts are treated to recycle the alumina by a two-step process: the first step involving conversion of the alumina to aluminum sulfate by reaction with gaseous sulfur trioxide, and the second step involving conversion of the aluminum sulfate to an aluminum hydroxide compound by reaction with an aqueous hydroxide. Both reactions are topochemical, and the aluminum hydroxide compound is prepared in particulate form.

Abstract: A process for removing organic contaminants from a mineral ore such as bauxite. The ore is washed with an aqueous solution containing caustic soda, sodium carbonate or mixtures thereof in an amount up to about 80 g/l total alkali content (expressed as sodium carbonate equivalent). The ore is preferably washed at a temperature of about 95.degree. C. for about 5 hours with a solution containing about 20 g/l total alkali content. In a preferred embodiment, the ore is separated from a rinse solution containing degradation products of organic contaminants, and the washed ore is then dissolved in a caustic solution to produce Bayer process liquor. This process provides a means to reduce the organic carbon concentration in Bayer process liquor, with resultant increase in productivity of the Bayer process.

Abstract: Heat treated anionic clay mineral is an improved catalyst for the conversion of acetone to mesityl oxide and isophorone as well as for the aldo condensation of other carbonyl-containing compounds.

Abstract: Bayer process caustic liquors are purified by treating the liquors with an organic solvent of relatively low boiling point, such as methanol, which causes the precipitation of inorganic carbonate and/or sulfate salt from the treated liquor. The treating solvent can be readily recovered for reuse.

Abstract: The process of the present invention resides in the production of an extremely pure basic aluminum-sodium carbonate of the dawsonite type. In the process of the present invention, aluminum hydroxide is reacted with an aqueous sodium bi-carbonate solution at a temperature between 160.degree. and 240.degree. C. and at a pressure of 5-50 atm. The reagents from an aqueous suspension which is stirred throughout the duration of the reaction and the temperature of the reaction is chosen in accordance with the length of crystalline fiber which is to be produced.

Abstract: A process for recovering gallium from alkali aluminate solutions which consists in that the starting alkali aluminate solution is neutralized to a concentration of the caustic alkali of from 0.1 to 10 g/l, whereafter the neutralized liquor is evaporated to a concentration of the caustic alkali therein of from 30 to 150 g/l. Then the evaporated solution is corrected to obtain the ratio between the alkali metal oxide and alumina of above 2.0. The corrected solution is treated with a liquid alloy of gallium containing an element possessing an oxidizing potential exceeding that of gallium to give a concentrate containing more than 90% of gallium by mass, wherafter gallium of a higher purity grade is recovered from the resulting concentrate by the electrochemical method.

Abstract: A novel process for recovering nickel metal from aqueous ammoniacal nickel solutions such as leach liquors at or close to ambient temperatures and pressures. The process comprises contacting the nickel solution with carbonyl ferrate ions such as HFe(CO).sub.4.sup.- or Fe(CO).sub.4.sup.-- in the presence of carbon monoxide to produce nickel carbonyl. The nickel carbonyl is collected as a gas, concentrated, and decomposed to produce nickel metal and carbon monoxide. The carbonyl ferrate ions may conveniently be produced by subjecting an iron pentacarbonyl solution to an aqueous alkaline solution containing potassium hydroxide or the like. The nickel depleted ammoniacal liquor is purged of iron resulting from the nickel carbonylation treatment by oxidizing the ferrous values to iron oxide and may thereafter be recycled to solubilize additional nickel values.

Abstract: Floride and aluminum values, as well as carbon, are recovered from waste cathode liner material from aluminum electrolytic cells by leaching of the liner at ambient temperature with a caustic solution, followed by precipitation of sodium fluoride by saturating the leach liquor with a compound which suppresses the solubility of sodium fluoride in the leach liquor. Ammonia is a preferred compound. Aluminum compounds, as well as the carbon values, are also recovered. Treating chemicals used in the process are recycled. The process is essentially a closed-cycle process with substantially no discharge of effluent.

Abstract: Process for treating solutions from the Bayer process, enabling amounts of sodium carbonate and sodium oxalate or sodium salts of organic acids corresponding to the amounts of these compounds dissolved during the attack on a bauxite to be removed by means of a barium compound, and without consumption of the latter.

Abstract: A process is provided which allows control of the impurity level of Bayer process streams with simultaneous generation of an environmentally acceptable effluent and recovery of valuable dissolved aluminum and sodium values. The process involves carbonation of a blow-down stream at 40.degree.-100.degree. C to produce sodium dawsonite [NaAl(OH).sub.2 CO.sub.2 ] and an effluent essentially free of dissolved alumina and significantly depleted in dissolved sodium. The sodium dawsonite can be used as such or returned to the Bayer process after thermal decomposition to sodium aluminate. The effluent can be directly discharged into natural receiving bodies without further treatment.

Abstract: A hydrochloric acid leach solution is subjected to a first cycle of extraction by an organic solvent, solvent washing and stripping so that the stripping liquor contains iron, zinc, cadmium and gallium while the liquor constituted by the first raffinate at the outlet of the extraction unit mainly contains nickel, cobalt and copper. In a second extraction cycle, the stripping liquor contains copper while the second raffinate mainly contains cobalt and nickel. In a third extraction cycle, the stripping liquor contains cobalt while the third raffinate mainly contains nickel.

Abstract: An improved process for preparing highly concentrated salt solutions of metals of high purity from waste metal sludges at superior dissolution rates is achieved by preparing, concentrating and washing the sludge containing insoluble metal hydroxide under specific conditions to safeguard against the solids being exposed to air or dried out. The wet sludge is then dissolved in a dilute acid. The resultant solution can be used directly e.g. as make up in many electrolytic metal finishing processes to compensate for drag out losses occurred, or as the primary metal source in electrolytic processes employing insoluble anodes. Other specific uses for the process include the preparation of aluminum sulfate coagulants.

Abstract: A method for processing bauxites according to the Bayer technology, with an increased yield in Al.sub.2 O.sub.3 and with decreased caustic soda losses, starting particularly from goethite bauxites of boehmite and/or diaspore type and carrying out the digestion at 180.degree.C to 300.degree.C using an aluminate liquor containing Na.sub.2 O.sub.caustic in a concentration of 80 to 300 g./l. The digestion is carried out in the presence of a calcium compound in an amount corresponding to 2 to 6 % of CaO calculated for the dry weight of bauxite and of a sulfate salt in an amount corresponding to 1.0 to 7.0 g./l. of sulfate ion concentration, whereby the goethite content of the bauxite is converted into hematite. The process provides advantageous conditions for the complete dissolution of the boehmite and diaspore content of bauxite in the vicinity of the equilibrium molar ratio, and enables to recover efficiently the caustic soda losses in the Bayer process itself, requiring no supplementary operation.