Abstract: The present invention relates to a method of producing nanophase Cu—Al2O3 composite powder by means of 1) the producing precursor powders by centrifugal spray drying process using the water base solution, in which Cu-nitrate (Cu(NO3)23H2O) and Al-Nitrate (Al(NO3)39H2O) are solved to the point of final target composition (Cu-1 wt %/Al2O3),2) the heat treatment process (desaltation process) at the 850° C. for 30 min in air atmosphere to remove the volatile components such as the moisture and NO3 group in precursor powder and simultaneously to synthesize the nano CuO—Al2O3 composite powders by the oxidation of corresponded metal components and 3) the reduction heat treatment of CuO at 200° C. for 30 min in reducing atmosphere to produce the final nanophase Cu—Al2O3 composite powders with the size below 20 nm.

Abstract: In one embodiment of the present invention, the material is a non-linear optical compound with a general chemical formula (&Sgr;iM&agr;i1)(&Sgr;jM&bgr;j2)(&Sgr;kM&ggr;k3)Be2O5  Formula 1 wherein M1, M2, and M3 are mono-, di-, or tri-valent metal ions respectively; wherein (&Sgr;i&bgr;i)=X and ranges from 0 to 6, (&Sgr;j&bgr;j)=Y and ranges from 0 to 3, and (&Sgr;k&ggr;k)=Z and ranges from 0 to 2, (hereinafter referred to as “MBE2O5” compounds).

Abstract: Herein disclosed is 6 indium tin oxide (ITO) fine powder whose crystal form is a corundum type one and which has a true specific gravity of not less than 6.5 g/cc, a green density of not less than 3.0 g/cc, and a Seebeck coefficient of less than 30 .mu.V/cc at ordinary temperature and less than 80 .mu.V/cc after heating at 200.degree. C. The ITO fine powder can be prepared by a method which comprises the steps of neutralizing an aqueous solution containing an indium salt and a tin salt with ammonia to thus control the pH of the reaction solution to the range of from 6.8 to 7.5; separating the resulting neutralized precipitates through filtration; drying and washing the precipitates; calcining the precipitates in the air at a temperature ranging from 550 to 700.degree. C.; and then reducing-burning at a temperature ranging from 350 to 450.degree. C. in a reducing atmosphere.

Abstract: A process for making a crystalline solid-solution powder which involves reacting at least two reactants in a plasma arc of a plasma chamber and blast-cooling the resultant product in a high velocity gas stream to form the powder. The first reactant is a molten metal alloy and the second reactant is a gas. The reaction is carried out in a plasma arc and the products rapidly cooled by a gas stream acting at the outlet opening of the plasma chamber. The crystalline solid-solution powder formed by the process has a low electrical resistivity. If an indium-tin alloy is used as the first reactant and oxygen as the second reactant, there is obtained an indium-tin-oxide (ITO) crystalline solid-solution powder which, when compacted to 40% of its theoretical density, has an electrical resistivity in the range of about 2 .OMEGA.cm. This ITO crystalline solid-solution powder is particularly suitable for preparing an ITO target, with high electrical conductivity and thus high achievable sputtering rates.

Abstract: A new family of crystalline and microporous compositions having indium and silicon as essential framework elements have been synthesized. These compositions are characterized by unique x-ray diffraction patterns and an empirical formula of:A.sub.p (In.sub.1-n M.sub.n).sub.y Si.sub.1-z Ge.sub.z O.sub.xwhere A is a cation such as sodium or potassium and M is a metal having a valence of +3, +4 or +5 such as iron (+3), titanium (+4) and niobium (+5).

Abstract: This invention relates to synthetic chalcoalumite-type compounds represented by formula (1) below:M.sup.2+.sub.a-x/2 Li.sub.x.sup.1+ Al.sub.4.sup.3+ (OH).sub.b (A.sup.n-).sub.c.mH.sub.2 O (1)(whereinM.sup.2+ represents at least one of the following divalent metal ions: Zn.sup.2+, Cu.sup.2+, Ni.sup.2+ and Mg.sup.2+,a is 0.6<a<1.2,x is 0<x<1.4,b is 11<b<13,A.sup.n- is at least one member of the group consisting of SO.sub.4.sup.2-, HPO.sub.4.sup.2-, CO.sub.3.sup.2-, SiO.sub.3.sup.2-, SO.sub.3.sup.2-, HPO.sub.3.sup.2-, H.sub.2 PO.sub.4.sup.-, NO.sub.3.sup.- and OH.sup.-,c is 0.5<c<1.2, andm represents a number of 1 to 4)and processes for their preparation. The synthetic chalcoalumite-type compounds of the present invention are conveniently used for adsorbing agents of acidic substances, anion exchangers, infrared absorption agents for agricultural films, deodorants and recording media for ink jet, etc.

Abstract: A method for selecting chemical grade silicon metalloid having improved performance in a direct process for making organohalosilanes. The method comprises (A) heating a chemical grade silicon metalloid sample at a temperature ramp speed controlled to effect a stepwise reduction of oxide impurities present in the chemical grade silicon metalloid to a temperature greater than about 2300.degree. C. in the presence of a carbon source thereby effecting the formation of a reduction product consisting of carbon monoxide and carbon dioxide, (B) determining the amount of the reduction product formed above a temperature of about 1900.degree. C., and (C) selecting a chemical grade silicon metalloid for use in the direct process for making organohalosilanes based upon the amount of the reduction product formed above a temperature of about 1900.degree. C.

Abstract: The present invention concerns a novel photocatalytic composition, a photocatalytic element and a novel method for the photocatalytic treatment of effluents, comprising a gaseous or aqueous solution of the organic compounds to be destroyed.This novel photocatalytic composition consists of an inorganic gel comprising a photocatalyst and an aluminosilicate inorganic polymer binder of the Imogolite type.This composition destroys organic compounds efficaciously.

Abstract: According to the method, an aqueous salt solution containing either tin, indium or both, are mixed with an alkali to produce a slurry containing precipitated particles. Then, the slurry is maintained at a predetermined temperature range for a time sufficient to convert the precipitated particles to larger size particles by coagulation or agglomeration. The resulting slurry is then dried and calcined to produce a mixed power. The mixed power is ball milled, press molded and/or cold isostatic press (CIP) molded. The molded body is then sintered to form an ITO sintered body. The ITO sintered body obtained by this process offers superior sinterability whose theoretical density can reach more than 95%.

Abstract: Liquid gallium or gallium alloy is utilized as a mercury substitute for a variety of applications. The liquid gallium or gallium alloy is either free of metal oxides or has only very low quantities of metal oxides.

Abstract: Zinc oxide ceramics and a method for producing the same are provided wherein zinc oxide varistors for low and high voltages having excellent electric characteristics and high reliability upon DC loading and surge can be obtained in high yield by low-temperature sintering. 0.2 to 20 parts by weight of a mixed powder of bismuth oxide, titanium oxide and antimony oxide is treated in advance at a temperature of 850.degree. C. or less. The synthetic powder thus obtained is added to 100 parts by weight of ZnO material powder to produce ceramics. By using the ceramics for a zinc oxide varistor, a zinc oxide varistor for a low or high voltage can be produced in high yield, which can be sintered at a low temperature and is excellent in electric characteristics and reliability upon DC loading and surge. Aluminum is sprayed on both sides of a sintered body so that an aluminum layer is formed. Copper is sprayed on the aluminum layer so that an electrode is formed. A lead wire is bonded to the electrode.

Abstract: An electro-conductive oxide particle comprising indium atoms, antimony atoms and oxygen atoms in a molar ratio of In:Sb:O being 1:0.02-1.25:1.55-4.63 and having a primary particle diameter of from 5 to 500 nm.

Abstract: The invention relates to a double oxide which is transparent and electrically conductive. This double oxide has a defective fluorite crystal structure and is represented by a formula of In.sub.3 Sb.sub.1-X O.sub.7-.delta. where X is in a range of from about -0.2 to about 0.2, and .delta. is in a range of from about -0.5 to about 0.5. The double oxide is good in electric conductivity and high in visible light transmittance, in particular in short wavelength region of visible light, as compared with conventional oxide materials.

Abstract: A method of treating spent potliner material from aluminum reduction cells is disclosed. The spent potliner material is introduced into a sulfuric acid digester to produce a gas component including hydrogen fluoride and hydrogen cyanide and a slurry component including carbon, silica, alumina, sodium sulfate, iron, calcium and magnesium. The gas component is recovered and heated an effective amount to eliminate hydrogen cyanide and produce a remaining gas component including CO.sub.2, H.sub.2 O, nitrogen oxides and HF. The remaining gas component is directed through a water scrubber to form hydrofluoric acid, and the hydrofluoric acid is admixed with aluminum hydroxide to create aluminum fluoride. The slurry component is rinsed with water to separate a first solid fraction containing carbon, alumina and silica from a second liquid faction. The pH of the liquid fraction is adjusted to first create and separate aluminum hydroxide and then to separate sodium sulfate.

Abstract: Applicant has discovered that aliovalently doped zinc-indium-oxide where In is 40-75% of the metal elements can achieve electrical conductivity comparable to wide band-gap semiconductors presently in use while exhibiting enhanced transparency in both the visible and infrared. The material can be doped to resistivity of less than 1 milliohm-cm by small quantifies of aliovalent dopants, such as tetravalent atoms. It can be deposited on glass substrates in amorphous and polycrystalline films.

Abstract: Electro-conductive oxides showing excellent electro-conductivity, electrodes using the electro-conductive oxide and methods for manufacturing the same are described. The electro-conductive oxides are represented by the general formula:M(1).sub.x M(2).sub.y In.sub.z O.sub.(x+.spsb.3.sub.y/.spsb.2.sub.+.spsb.3.sub.z/.spsb.2.sub.)-d.The above electro-conductive oxides show not only excellent electro-conductivity but also excellent transparency all over the visible region and therefore they are particularly useful as, for example, electrodes for liquid crystal displays, EL displays and solar cells, which require light transmission.

Abstract: An object of the present invention is to provide a composition for use in a formation of transparent and electrically conductive film having a low electric resistance and a high transmittance and a method for making the film mentioned above. A mixture of inorganic indium compound and organic tin compound is combined with organic compound capable of coordinating with either of indium and tin to form an organic solution. When the mixture is heated, the inorganic indium compound and the organic tin compound coordinating partially with the organic compound react with water of crystallization of inorganic indium compound. The organic tin compound is partially subjected to hydrolysis to form an intermediate complex compound including indium and tin. This suppresses the evaporation of tin and generates a uniform film having a high transmittance and a low electric resistance.

Abstract: The present invention discloses a process for preparing a fine-particulate metal hydroxide comprising aluminum hydroxide as a major component which comprises continuously supplying water and a mixture of an aluminum alkoxide and at least one alkoxide of a metal selected from Mg, Ca, La, Fe, Si, Ti and Zr, to a high shear rate stirring area and a process for preparing a fine-particulate metal oxide comprising aluminum oxide as a major component which comprises drying and then calcining said metal hydroxide at 500.degree.-1500.degree. C.

Abstract: A process for treatment of hazardous liquid waste comprising trace amounts of hazardous elements in solution as oxyanions by oxyanion fixation within ettringite and related minerals. In accordance with the disclosed process, reagents for forming ettringites are mixed with the waste stream resulting in the formation of oxyanion-substituted ettringite and related materials. The resulting ettringite and related minerals are separated by filtration from the liquid. Thereafter, the liquid, having an elevated pH, is neutralized by carbon dioxide sparging resulting in precipitation of excess reagents in the liquid. Thereafter, the precipitates are filtered, producing a clean liquid.

Abstract: A process for treating sodium hydroxide waste liquor containing aluminum, comprising the steps of: adding, to aluminum-containing sodium hydroxide waste liquor, at least one of MgO and Mg(OH).sub.2 in an amount of 0.5 to 3 moles with respect to 1 mole of aluminum to cause a reaction at 70.degree. C. or more; and separating and removing a precipitated magnesium-aluminum compound is disclosed. The present invention makes it possible to recover recyclable sodium hydroxide from an aluminum-containing sodium hydroxide waste liquor. Even if the recovering procedure is repeated, no carbonate ions are accumulated. Therefore, it is possible to prevent degradation of the treating solution containing sodium hydroxide. Further, the by-product is a useful compound, and thus, there is no problem in the reprocessing or disposal of the by-product.

Abstract: A stable aqueous sol of amorphous alumina containing Al.sub.2 O.sub.3 up to 15% by weight and 0.1 to 0.5 gram equivalent of an anion of acid to 1 mol of aluminum in the sol, in which the colloidal particles of amorphous alumina have a controlled thickness in a range of 20 to 100 millimicrons and a uniform length in a range of 200 to 500 millimicrons is produced by a process comprising feeding an aqueous solution of an acid into an aqueous slurry containing 1 to 7% by weight of metallic aluminum, 10 to 200 ppm by weight as Si0.sub.2 of a water-soluble silicate and 0 to 20 ppm by weight of a water-soluble sulfate as S0.sub.4 to the water in the slurry while maintaining the slurry at a temperature of 80.degree. C. to boiling point under normal pressure, said acid being in an amount of 0.1 to 0.5 gram equivalent to 1 mol of the metallic aluminum in said slurry, at a rate of 0.001 to 0.

Abstract: Disclosed is a boride material for electronic elements, which is represented by a chemical formula of A.sub.1-x E.sub.x B.sub.12 (where A is Zr of Hf, E is Sc or Y, and 0.1.ltoreq.x.ltoreq.0.9) and the crystal system of which is a cubic one at a temperature not lower than its phase transition temperature and is a hexagonal one at a temperature not higher than its phase transition temperature. The boride material is prepared by mixing oxide powders or sulfate powders of the constitutive elements A and E and a boron powder followed by shaping the powder mixture and then sintering the shaped body.

Abstract: An aggregated synthetic hydrotalcite having a substantially spheroidal shape and an average diameter of up to about 60 .mu.m is disclosed. The aggregates are composed of individual platy particles having plate diameters of from about 0.05 to about 10 .mu.m. The material has a low tapped density, a high pore volume and a high specific surface area.A process for producing the product is also disclosed. Product particle size is determined by controlling process parameters including reaction temperature and pH, stirring speed of the reaction mixture, and reactant addition rates and concentrations, including aqueous solutions of soluble magnesium and aluminum salts, which are mixed in a molar ratio of from about 2.5:1 to 4:1, and a basic solution containing excess carbonate and base to maintain the reaction mixture at a pH of from about 8.5 to about 9.5.

Abstract: A method for producing an anion intercalated hydrotalcite without first forming hydrotalcite and then having to activate the hydrotalcite prior to substituting anions in the hydrotalcite structure. The method includes reacting an activated magnesia with an aqueous solution of aluminate, anion, such as bromide, chloride, sulfate, borate and combinations thereof and hydroxyl ions. The method can be carried out at atmospheric pressure to form hydrotalcite in high purity and high yield. In a preferred embodiment of the invention, the aluminate solution is formed from sodium aluminate, sodium bromide and sodium hydroxide and the aqueous solution is substantially carbonate free. Other anion intercalated hydrotalcites can also be produced by the method of the present invention.

Abstract: A stabilizer for resin, which is composed of a lithium aluminum complex hydroxide salt represented by the following formulaAl.sub.2 Li(OH).sub.6).sub.n X.mH.sub.2 O . . . (1)wherein X is an inorganic or organic anion, n is a valence number of anion X, and m is a number of not more than 3.A chlorine-containing polymer composition comprising a chlorine-containing polymer and 0.01 to 10 parts by weight, per 100 parts by weight of the chlorine-containing polymer, of the above stabilizer. There is also provided an olefin-type resin composition comprising an olefin-type resin containing halogen-containing catalyst residues and 0.01 to 10 parts by weight, per 100 parts by weight of the olefin-type resin, of the above stabilizer. The stabilizer has excellent heat stabilizing action.

Abstract: Aluminum magnesium hydroxy compounds of the formulaAl.sub.x Mg.sub.y (OH).sub.35-z R.sub.z.nH.sub.2 Oin which R represents an anion of at least one monocarboxylic acid having from 2 to 22 carbon atoms, and n, x, y and z are defined by: ##EQU1## are described.

Abstract: Zirconium-doped pseudoboehmite with the following properties: zirconium content of 0.5 to 10 mol % relative to Al water content of 20 to 35 weight percent total of the anionic impurities less than 0.5 weight percent. It is synthesized by a process wherein zirconium salt is added in calculated quantity to an aqueous aluminum sulfate solution, the resulting mixture is fed simultaneously with a sodium aluminate liquor into a water pool having a temperature of 50.degree. to 100.degree. C., thereby precipitating zirconium-doped alumina gel while a pH of 3.5 to 8 is maintained, the pH of the suspension is adjusted after addition of the aluminum sulfate solution to 8.5 to 10.5 by further addition of sodium aluminate liquor, the suspension is digested if necessary at the pH of 8.5 to 10.5 and the temperature of 50.degree. to 100.degree. C. for a period of up to 24 hours, the formed pseudoboehmite crystals are filtered off, the filter cake is redispersed with water and the suspension is sprayed-dried.

Abstract: An improved method for producing aluminum titanate powder material for making aluminum titanate ceramics.

Abstract: A process for treating spent potlining from the electrolytic smelting of aluminum in cryolite includes incinerating the potlining to combust carbonaceous material to form an ash at a temperature low enough to maintain low fluorine vapor pressures, admixing siliceous material with the potlining either before of after the ash-forming stage, and heating the ash and siliceous material to form a glassy residue.The residue formed by the process of the present invention produces a spent potlining suitable for landfill characterized by a low leachability of fluorine in water.

Abstract: An efficient method is proposed for the recovery of a trace amount of a gallium value from an aqueous solution containing a large amount of an aluminum salt as the principal solute as in the solution which is prepared by dissolving the precipitates obtained by neutralizing a Bayer's solution with carbon dioxide in hydrochloric or sulfuric acid. The method comprises admixing the aqueous solution with a water-soluble ferrocyanide compound, e.g., sodium ferrocyanide, as a precipitant of gallium ferrocyanide in such a controlled small amount as not to exceed 2.5 times by moles of the gallium ions in the starting solution so that coprecipitation of aluminum ferrocyanide is minimized.

Abstract: The present invention provides a process for treating spent potlining from the electrolytic smelting of aluminum in cryolite including burning the spent potlining to form an ash, mixing with a siliceous material either before or after the ash-forming step, and heating to form a residue suitable for landfill. The ash and siliceous material are mixed in a specified mole ratio of at least about 1.4 silicon to sodium. The process further includes cooling the residue rapidly.The residue formed by the process of the present invention produces a spent potlining suitable for landfill characterized by a low leachability of fluorine in water.

Abstract: Continuous production of aluminum hydroxycarbonate gel by continuous reaction of aluminum salt solution with mixed alkaline carbonate and bicarbonate solution under homogeneous conditions in a relatively small reaction vessel, and continuing the reaction in a subsequent reaction vessel under controlled pH. The product gel is separated from the non-aluminum cation containing reaction mixture within less than about 6 hours, whereby formation of poorly soluble addition reaction products such as dihydroxy aluminium sodium carbonate, which contribute undesired non-aluminum cations to the gel product, is reduced. The aluminum salt solution is adjusted in pH by adding to it a portion of the mixed carbonate and bicarbonate solution to obtain a clear solution of pH 3.5 to 4.0. This results in a smooth, creamy gel with less objectionable chalky mouth feel.

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 composite ceramic material having improved properties is disclosed as well as several methods for preparing the same. The composite powder is substantially comprised of zirconia and spinel phases, produced by precipitation and calcination of the precipitate of the oxide forming precursor salts. A preferred method for introducing the zirconium is as a soluble and/or decomposable salt during precipitation of the spinel forming hydroxyl or halo hydroxyl spinel forming salts. The zirconium salt decomposes to zirconia during calcining and/or sintering of the powder resulting from the precipitation. A preferred composite is that obtained from magnesium and aluminum salts, resulting in a MgAl.sub.2 O.sub.4 spinel and intimately admixed ZrO.sub.2 which contains a stabilizing agent.

Abstract: A fine particulate .alpha.-Sialon powder with a narrow particle size distribution, thus having an excellent sinterability, can be produced by using as the starting materials (a) amorphous silicon nitride, (b) metallic aluminum or aluminum nitride, and (c) an oxide of a metal which can be incorporated in the interstices of .alpha.-Sialon lattice or a metal compound capable of forming such a metal oxide upon thermal decomposition, and optionally, (d) an oxygen-containing compound of alumina or silicon, followed by heat treatment of the resultant mixture.

Abstract: Disclosed is a method of making aluminum borate fibers comprising the steps of preparing an aluminum borate gel by reacting aluminum salt in a solution with ammonium borate and heating the gel to form the aluminum borate fibers.

Abstract: A process for preparing a zirconia-alumina base composite ultra-fine powder is described, including the steps of: mixing an aluminum salt or an alumina hydrate with an aqueous zirconium oxychloride solution, with or without metal salt acting as a stabilizer; mixing urea or a substance capable of generating ammonia by hydrolysis with the resulting mixture; and allowing the mixture to react at a temperature of 140.degree. to 300.degree. C. and a pressure of 4 to 150 kg/cm.sup.2 in a high-temperature and -pressure vessel. The reaction product is further dried, calcined and crushed to obtain an ultra-fine powder.

Abstract: Gallium is recovered from gallium arsenide by reacting and dissolving the gallium arsenide with an oxidant and a complexing agent, especially with water insoluble hydroxamic acids with mild conditions, e.g. with aqueous hydrogen peroxide and mild temperature, to effect separation of gallium hydroxamic acid chelates from water soluble arsenic compounds.

Abstract: The invention relates to gas-tight sintered translucent aluminum oxide having a density of at least 99.5%, which contains at most 1000 ppm by weight of MgO. According to the invention, the aluminum oxide also has a content of Er.sub.2 O.sub.3 lying between 20 ppm by weight and 200 ppm by weight. The material thus obtained has a great mechanical strength, a high resistance to attack by sodium and a satisfactory translucence. Thus, the material is very suitable for use as wall material for the discharge vessels of high-pressure discharge lamps.

Abstract: The invention is drawn to a continuous process for the recovery of alumina from ores by mixing with an alkali bisulfate, calcining below 450.degree. C. to form the corresponding double salt, washing with water, and separating the insoluble residue from the solubilized aluminum, precipitating impure aluminum, resolubilizing aluminum with sodium hydroxide to form soluble sodium aluminate and separating it from the insoluble impurities, treating the resulting solution to form aluminum precipitate, separating the aluminum and calcining it to form alumina.

Abstract: A process for the recovery of valuable metals from roasted crude-oil sulfur-extraction catalyst waste is disclosed. In this process the value metals can be separated from aluminum in a single stage by treating the waste at elevated temperature and pressure with such an amount of sulfate solution that the waste dissolves and the aluminum simultaneously precipitates as alunite, which is separated from the solution which contains the other value metals. A sulfate solution is preferably added in such an amount that the concentration of sulfuric acid in the solution is 2-30 g/l at the end of the stage.

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: Recovery of fluoride values from carbonaceous waste cathode materials is achieved by reacting the waste materials with oxygen, water, and sulfur dioxide at temperatures between about 600.degree. C. and 1200.degree. C.

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: 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: 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 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: This invention relates to the disposal of aluminum hydrocarbyl, aluminum hydrocarbyloxy, aluminum halide or aluminum hydride waste materials. Such materials are used as catalysts and may be present alone as well as in combination with similar compounds of other elements typically of Group IV-B, V-B, VI-B, VII-B or VIII. The present disposal process seeks to minimize environmental pollution and provide a product that is suitably used as land-fill. In the process of the invention, a system containing an aluminum hydrocarbon, hydrocarbonoxy, halide or hydride waste stream either with or without a co-present compound of another element as set forth is reacted with a hydroxide or carbonate of a Group I-A, II-A, IV-A, or V-A element under substantially anhydrous conditions. The reaction is comparatively mild and is suitably conducted in ordinary steel equipment without excessive corrosion problems. Diluents co-present with the waste materials are recovered for recycle in anhydrous form without requiring drying.

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.]. .Iadd.activated magnesia is produced by .Iaddend.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.