Abstract: A ceramic sintered body and a method for manufacturing the same in which the body includes a first material having at least one of a precursor and a metastable material of the final sintered body and a second material morphologically related to the first material and added to the first material to affect transformation of said first material into the desired crystalline form of the ceramic sintered body, in which method transformation of a metal oxide compound from one phase to another, where the compound has a high activation energy and is confronted with a high nucleation energy barrier to the transformation, produces the body and includes the steps of making a mixture by bringing a multiplicity of particles of the compound into intimate contact with the multiplicity of nucleation particles having crystallographically related structure to act as nuclei for the transformation and sintering the resulting mixture to transform the compound from one phase to another by nucleation and growth, independently of gro

Abstract: A boehmite or boehmite precursor can be improved in its dispersibility by subjecting it to a hydrothermal treatment at a pH of less than 3.5 and at elevated temperature and pressure.

Abstract: Aluminum oxide ceramic composite articles having high flexural and tensile strength are produced by introducing a liquid aluminum oxide precursor material into a ceramic reinforcement fabric, curing the precursor material at an elevated temperature, and converting the cured precursor material to an aluminum oxide ceramic by pyrolysis at temperatures which do not result in the degradation of the reinforcement material. Such ceramic composite articles are particularly useful for applications requiring a low dielectric constant and a high mechanical strength.

Abstract: A process is disclosed for producing aluminum hydroxide in the form of gibbsite in particular shapes, suitable for use as a filler, flame retardant and/or fibrous reinforcement. The process includes the steps of crystallizing gibbsite from a Bayer process sodium aluminate liquor, in the presence of an additive comprising either a hydroxycarboxilic acid for producing needle shaped, rod-like hydrargillite or in the presence of a polyalcohol, fatty acid or lithium compound for producing platy or tabular gibbsite.

Abstract: A novel process is described for the preparation of monodisperse ceramic ders wherein particulate oxides or hydroxides are obtained by reaction of hydrolysable compounds with water. The reaction is carried out in the presence of a complexing agent and, optionally, a stabilizer.

Abstract: A reduced chromium-ore bearing powder used for production of a chromium-containing steel in a converter, is produced by a reduction of chromium ore-powder having a particle-diameter of 3 mm or less by a carbonaceous reducing agent having a particle diameter of 3 mm or less in an inert-gas atmosphere, while the chromium-ore powder and carbonaceous reducing agent are stirred and mixed with each other in the reaction chamber (5).The reduced chromium-ore powder has 3 mm or less of particle diameter. Acid-soluble chromium is in an amount of 85% or more of the total chromium, and acid-soluble iron is in an amount of 95% or more of the total iron.

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

Abstract: A process for forming a structure of aluminium components comprises pre-treating aluminium sheet to produce an inorganic non-metallic surface coating thereon, forming the pre-treated sheet to produce components of desired shape and applying adhesive to the components and securing them together by means of the adhesive. Generally, an adhesive-compatible press lubricant is present on the sheet when it is formed. The invention also includes aluminium sheet carrying the inorganic non-metallic surface coating and a press lubricant thereon.

Abstract: A method for producing boehmite, which comprises subjecting aluminum hydroxide dispersed in water to treatment under heat and pressure in the presence of maleic acid and/or malic acid.

Abstract: Mixed oxides of alumina and zirconia having a controlled granulometric distribution, consisting essentially of spherical, submicronic particles, wherein zirconia is distributed uniformly in alumina and may reach 38% by weight, said zirconia being in the stabilized form at room temperature in the tetragonal phase, after having subjected the amorphous hydrated composite oxides to thermal treatments, wherein occurs the transition of zirconia to the tetragonal phase.

Abstract: The invention relates to a method of manufacturing permeable mineral membranes.The method of the invention is characterized in that a thin layer of gel of peptised hydroxide of at least aluminum is deposited on a permeable perous substrate and the resulting membrane is dried and fired at a temperature between 500.degree. and 1100.degree. C.The resulting membranes can be used for isotopic separation of gases or for filtration and ultrafiltration.

Abstract: Alumina particles having average particle size of about 1-20 microns are converted to alpha alumina in a steam-fluidized bed maintained at about 380.degree.-600.degree. C. and a pressure greater than about 1000 psig. Acidifying the steam reduces average crystallite size of the product and lowers content of some impurities. A preferred product is alpha alumina having an average crystallite size of less than about 0.2 micron.

Abstract: Alpha-alumina consisting essentially of solid, spherical, non-aggregated particles, having a diameter from 0.06 to 2 .mu.m, a polydispersion index below 2.0, a total porosity below 0.3 cc/g, a specific surface area from 0.7 to 80 m.sup.2 /g, and an apparent density of the particles from 3.20 to 3.94 g/cm.sup.3. The alpha-alumina is prepared by a process consisting, in that an alpha-alumina precursor, having a water content from 2 to 33% by weight, at starting temperatures ranging from room temperature to 850.degree. C., and consisting essentially of solid spherical, non-aggregated particles, having a particle diameter from 0.07 to 2.3 .mu.m and a polydispersion index of .ltoreq.2.0, is subjected to a heat-treatment at temperatures ranging from 1130.degree. to 1700.degree. C., said precursor being instantaneously brought from the starting temperature to the treatment temperature, and by carrying out the treatment during times, as generally indicated in the accompanying FIG.

Abstract: A process for removing mineral impurities such as metal oxides from coal and shale oil structures is disclosed. The process is carried out by subjecting crushed coal or shale to a hydrocarbon fluoride leaching solution, separating the HF leach liquor from the coal or shale, washing the coal or shale with water, leaching the washed coal or shale with hydrogen chloride solution, separating the HCl leach liquor from the coal or shale, washing the coal or shale with water, and removing residual impurities from the treated coal or shale by heating under a vacuum. The process allows for the recovery of carbons and hydrocarbons of high purity from coal or shale which do not require expensive emission control equipment when combusted.

Abstract: The present invention relates to the aluminum hydroxide having a specific surface area of at least 350 m.sup.2, preferably at least 400 m.sup.2, per g. and to a process for its preparation. The aluminum hydroxide should be capable of absorbing at least 1 g of fat per g. of material. The aluminum hydroxide is preferably part of a pharmaceutical preparation.

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: The invention relates to a process for manufacturing highly active, dispersed aluminum hydroxide, of low apparent density. First, unground, very fine grained aluminum tri-hydroxide, of which more than 99% of the grains are at most 3 .mu.m in size, is introduced continuously into a reactor along with a stream of hot dry air, is whirled up and strongly dispersed, heated to 400.degree.-600.degree. C. and shock dehydrated. The low apparent density aluminum oxide flowing out of the reactor in the hot air stream is precipitated out by suitable mechanical means, dispersed in mildly acidic or mildly basic water and rehydrated with the aid of heating. The invention also relates to shaped components of highly active, dispersed low apparent density aluminum oxide having a specific surface area of at least 200 m.sup.2 /g, a pore volume of more than 1.2 cm.sup.3 /g and adequate resistance to fracture and wear.

Abstract: This invention relates to a process for preparing catalyst supports with a wide pore size distribution by simultaneously titrating an acid aluminum species and a basic aluminum species, and interacting the precipitate with a phosphorus-containing oxide during the aging step. The porous resulting alumina supports have surface areas above about 300 m.sup.2 /g with a significant fraction of the pores having diameters greater than 350 .ANG. and a significant fraction of the pores having diameters less than 70 .ANG..

Abstract: High purity alumina with a low sodium content and with a friable, easily ball milled structure is produced in this invention through a modified sol-gel procedure which includes digestion of the contaminant containing aluminum metal with hydrochloric acid in the presence of excess aluminum, removal of the contaminants, seeding the resulting sol with high purity alumina, drying to a solid, and then calcining said seeded sol solids to produce said high purity alpha alumina.

Abstract: Disclosed is a process of preparing an alumina carrier which comprises kneading an amorphous alumina hydrate, whose alumina concentration is in the range of 28-35 wt. % and which has been obtained by neutralizing an aluminum sulfate solution with a sodium aluminate solution at two stages, while endowing said hydrate with sufficient shearing effect and alternate compression and expansion effect; extruding a resulting dough; drying and calcining the extrudates. According to this process, it becomes possible to control the growth of pseudoboehmite grains contained in the alumina hydrate by controlling the time required for kneading, and accordingly it becomes possible to control the pore distribution of the finally obtained alumina carrier.

Abstract: A high specific surface hydrargillite, well adopted as filler material or primer particulates in the production of finely divided aluminum trihydroxide by decomposition of Bayer process aluminate liquors, is readily prepared by (i) reacting an alkali metal aluminate with hydrofluoric acid at a temperature ranging from about 5.degree. to 95.degree. C., the amount of said hydrofluoric acid ranging from about 25% to 90% of that amount stoichiometrically required for complete neutralization of the alkalinity of said aluminate, (ii) optionally treating the hydrargillite precipitate which results at a temperature of from about 5.degree. to 95.degree. C. for from about one-half to 10 hours, and thence (iii) recovering said hydrargillite precipitate, preferably by filtering, washing and drying.

Abstract: An alpha alumina monohydrate, AlO(OH), gel is produced which is capable of readily dispersing in aqueous solutions to yield a shear-rate thinning mixture. The alpha alumina monohydrate is made by reacting an acid reactant and a base reactant, wherein at least one contains aluminum, in an aqueous medium in proportions to yield a mixture having a pH of from about 7.5 to 10. The gel is treated to remove much of the by-product salts. One preferred method involves filtering the reaction product to remove the by-product salts and then further washing the filter cake with water. Upon dispersing the filter cake in water it yields a shear-rate thinning liquid having increased viscosifying power per unit weight of the AlO(OH) and this is measured as a higher K value in the rheological power model.

Abstract: High surface area, wide-pore-containing porous alumina are prepared by mulling together alumina hydrogel and alpha alumina monohydrate, extruding, drying and calcining at 500.degree.-700.degree. C.

Abstract: High surface area, wide-pore-containing porous aluminas are prepared by mulling together aluminum nitrate derived hydrogels with sodium aluminate derived hydrogels, extruding, drying and calcining at 500.degree.-700.degree. C.

Abstract: The present invention is directed to a new and useful group of calcium, zinc and magnesium flocculating agents which may be beneficially utilized to treat and purify waste water and/or other waste liquids resulting from a variety of industrial processes. The general ion free formula of these inorganic flocculating agents is represented as follows:(Me.sub.2 O.sub.3).sub.m.sup..cndot. (Me.sub.2 O.sub.3 Cl).sub.(m+z).sup..cndot. (MeO).sub.n.sup..cndot. (SiO.sub.2).sub.t.sup..cndot. (SO.sub.4).sub.yThese flocculating agents may also be represented by the theoretical formula of:Me.sub.n.sup.II Me.sub.o.sup.II Me.sub.m.sup.III (OH).sub.p (SiO.sub.2).sub.t.sup..cndot. (Aci).sub.z (SO.sub.4).sub.ywhere:(a) Me.sub.n.sup.II is selected from the divalent cationic group consisting of: (1) Ca.sup.2+, (2) Mg.sup.2+ and (3) Ca.sup.2+ and Mg.sup.2+ ;(b) Me.sub.o.sup.II is divalent cationic Fe.sup.2+ ;(c) Me.sub.m.sup.III is selected form the trivalent cationic group consisting of: (1) Al.sup.3+, (2) Fe.sup.3+ and (3) Al.sup.

Abstract: The present invention relates to a method for producing sulphate-poor, polynucleate aluminium hydroxide sulphate complexes of the general formula[Al(OH).sub.x (SO.sub.4).sub.y (H.sub.2 O).sub.z ].sub.nin which n is an integer; x is 0.75-2.0; y is 0.5-1.12; x+2y is 3; z is 1.5-4 when the product is in solid form, and z>>4 when the product is in the form of an aqueous solution, an amorphous aluminium hydroxide being admixed with aluminium sulphate and/or sulphuric acid to y=0.5-1.12; preferably 0.5-0.75.

Abstract: An improved method of preparing alumina, including a first stage in which an alumina hydrogel is formed from seed aluminum hydroxide, and a second stage in which the alumina hydrogel is processed for conversion into alumina.

Abstract: A process is described for the direct chlorination of hydrated alumina (preferably alumina trihydrate) to aluminum chloride hexahydrate (ACH) by reaction with concentrated hydrochloric acid. Preferably all of the initial hydrated alumina is converted to ACH. The ACH partially calcined to form an amorphous mixture of aluminum oxides and oxychlorides. This mixture is then reductively chlorinated to form anhydrous aluminum chloride which is suitable as a source of electrolytically produced aluminum metal.

Abstract: An improved process for the preparation of alumina, including forming an alumina hydrogel from aluminum hydroxide, and processing the alumina hydrogel into alumina. The improvement involves the alumina hydrogel forming step which is connected in the presence of sulfate ion and which comprises providing, in a reaction zone, an aqueous slurry containing seed aluminum hydroxide and having a pH of 6-11, and feeding to the reaction zone an aluminum compound and a pH controlling agent for mixing with the aqueous slurry while maintaining the aqueous slurry at a temperature of at least about 50.degree. C. at feed rates so that the pH of the aqueous slurry is maintained within the range of 6-11 and that 0.2-5 mols/hour of aluminum components, in terms of elemental aluminum, are fed to the reaction zone per mole of the seed aluminum hydroxide originally contained in the aqueous slurry, whereby the seed aluminum hydroxide is caused to grow to the aluminum hydrogel.

Abstract: For the preparation of spheroidal alumina, an alumina sol having a solids content of more than 20 to 40% by weight of alumina is prepared from alumina hydrate, which consists of boehmite/pseudo-boehmite, by thorough stirring in aqueous dilute acid, and the alumina sol is caused in the presence of 1 to 10% by weight of urea to drop into a forming column whose top portion is filled with a liquid hydrocarbon and whose bottom portion is filled with an aqueous solution of ammonia and which is held at room temperature, and the thus formed spheroidal particles are dried and activated. The resultant spheroidal particles may also be subjected to a per se known aging treatment.

Abstract: Ultrapure and homogeneous boehmites and/or pseudo-boehmites, suitable, whether before or after drying and/or calcination, as, e.g., fillers, binders, thickeners, dispersing agents, and the like, are prepared (i) by admixing an amorphous aluminum hydroxycarbonate, itself advantageously prepared by carbonating an alkali metal aluminate with carbon dioxide and then filtering and washing the precipitate which results, with a solution of an acid, a base, a salt, or mixture thereof, with the pH of the resulting reaction medium being maintained at a value of less than 11, (ii) next heating such reaction medium at a temperature of less than 90.degree. C. for a period of at least 5 minutes, and (iii) then heating the reaction medium resulting from the step (ii) at a temperature ranging from 90.degree. C. to 250.degree. C.

Abstract: Process for the preparation of high purity alumina containing less than 0.1 weight percent of residual chlorine starting from impure aluminum chloride solutions, which process comprises a crystallization step to provide aluminum chloride hexahydrate crystals having a diameter of from about 400 to about 4000 micrometers in the presence of hydrochloric acid; washing the aluminum chloride hexahydrate crystals so obtained with pure hydrochloric acid; and pyrohydrolyzing the washed crystals of aluminum chloride hexahydrate at a temperature of from about 700.degree. to about 1300.degree. C., in which pyrohydrolysis a gas is forced through a layer of the washed aluminum chloride hexahydrate so as to remove the gaseous reaction products while obviating any possible movement of the solid by the gas, the process particularly producing transition aluminas simultaneously having a specific surface area greater than 100 m.sup.2 /g and a chlorine content less than 0.1 weight percent.

Abstract: A method of manufacturing spherical alumina particles which comprises the steps of digesting, at an elevated temperature and an elevated pressure, gibbsite with an aqueous hydrochloric acid solution and then forming an aqueous basic aluminum chloride solution; adding, at an elevated temperature, an aqueous ammonia to said aqueous basic aluminum chloride solution to form an alumina hydrosol containing ammonium chloride; commingling said alumina hydrosol with a gelling agent; thereafter dispersing droplets of said mixture in a suspending medium under conditions effective to transform said droplets into hydrogel particles; ageing said hydrogel particles first in said suspending medium and then in aqueous ammonia; and then washing said hydrogel particles with water, drying and calcining to obtain spherical alumina particles.

Abstract: High purity alpha-alumina bodies useful as catalyst supports are made by peptizing boehmite alumina in an acidic mixture containing fluoride anions, extruding the peptized alumina into shaped bodies and drying and calcining the bodies. The alpha-alumina bodies are characterized by a narrow pore-size distribution, having 85 percent of the total pore volume comprising pores of a diameter of from 10,000 to 200,000 Angstroms and by a surface area of less than one square meter per gram.

Abstract: An alumina composition comprising a microcrystalline boehmite-pseudoboehmite intermediate having from about 70 to about 85 weight percent of the total amount of Al.sub.2 O.sub.3 present in crystalline form. The composition is prepared by adding aluminum sulfate and sodium aluminate solutions to a mixture of water and aluminum sulfate solution to precipitate alumina and adjusting the pH to a pH higher than the precipitation pH. The reactant concentrations, and rates of addition, temperatures, and pH's in the precipitation are specifically controlled to form the boehmite-pseudoboehmite intermediate.

Abstract: Aqueous suspensions of alumina particulates, at least a portion of which comprising ultrafine boehmite, are prepared by maintaining a pH<9 aqueous formulation of poorly crystallized and/or amorphous activated alumina powder for such period of time as to effect the at least partial transformation of such alumina powder into ultrafine boehmite.

Abstract: A method of manufacturing spherical alumina comprising preparing a basic aluminum chloride solution having an aluminum concentration in the range of from 7 wt.% to 12 wt.% and a weight ratio of aluminum to chloride in the range of from 0.3 to 0.8 by reacting gibbsite with an aqueous hydrochloric acid solution at an elevated temperature, preparing an alumina hydrosol having an aluminum concentration in the range of from 9 wt.% to 15 wt.% and a weight ratio of aluminum to chloride in the range of from 0.8 to 1.5 by reacting the thus prepared solution with metallic aluminum at an elevated temperature, commingling this hydrosol with a gelling agent, dispersing the resulting mixture in the form of droplets in a suspending medium thereby to form hydrogel particles, ageing the thus obtained particles in said suspending medium and then an aqueous ammonia, washing with water, drying and calcining. The thus obtained spherical alumina is substantially free from sodium in spite of employing gibbsite as raw material.

Abstract: A catalyst carrier comprising gamma alumina wherein the apparent bulk density is in the range of from 0.65 g/cc to 0.71 g/cc, the total pore volume is in the range of from 0.55 cc/g to 0.65 cc/g, the content of pores having a diameter in the range of from 60A to 110A occupies at least 75% of the total pore volume, the surface area is in the range of from 210 m.sup.2 /g to 250 m.sup.2 /g and the attrition loss is less than 0.5 wt. %. This sort of catalyst carrier can be namufactured through a series of steps of: (a) preparing a first alumina hydrosol having an aluminum concentration in the range of from 9.8 wt. % to 14.4 wt. % and a weight ratio of aluminum to chloride in the range of from 0.95 to 1.20, (b) preparing a second alumina hydrosol having an aluminum concentration in the range of from 9.5 wt. % to 13.0 wt. % and a weight ratio of aluminum to chloride in the range of from 0.85 to 0.

Abstract: A process for the preparation of stable, liquid aqueous solutions of basic aluminium nitrate (aluminium oxynitrate) suitable for spinning into fibres, if desired after incorporation of a polymeric spinning aid, which process comprises reacting an aluminium oxide with nitric acid at below 25.degree. C. to form aluminium hydroxide, optionally washing the precipitate to remove undesirable ions, e.g. sodium ions, and digesting the precipitate in nitric acid or aluminium nitrate. Preferably the solution contains aluminium ions and nitrate ions in the molar ratio 1.6:1 to 2:1. Silica may be incorporated in the solution by reacting it with the nitric acid, together with the aluminium oxide, in the first step of the process.

Abstract: Alumina fibers are prepared by a method comprising(a) forming aluminum methoxide from aluminum alkoxides using methanol;(b) recovering aluminum methoxide as a solid precipitate phase, washing to remove higher alcohols and drying to recover a powder;(c) reacting the recovered powdered aluminum methoxide with dilute hydrochloric acid to form aluminum chlorohydrate; then(d) concentrating the aluminum chlorohydrate solution under vacuum to desired viscosity.

Abstract: A monolithic support for a catalyst suitable for use in controlling carbon monoxide emission is prepared by forming a homogeneous, fluid semi-solid mass by admixing colloidal .gamma. alumina, .alpha. alumina monohydrate and ceramic fibres with fluidizing and binding agents, water and a mineral acid, said acid being used in an amount sufficient to convert said .alpha. Al.sub.2 O.sub.3 monohydrate into a gel, forming the mass into a body of the desired shape, drying the body to substantially remove the added water, at least 10% of said added water being removed at a temperature lower than 50.degree. C., and heat-treating the dried body at 800.degree.-1000.degree. C.

Abstract: A process and apparatus for the manufacture of ceramic oxide fibers from solvent solution. The process comprises spinning a solution of a ceramic oxide precursor through openings having a diameter of from about 0.3 to about 1.5 millimeters, attenuating the resulting fibers with a stream of air to a diameter of less than 10 microns and heating the fibers in an oxygen atmosphere to form ceramic oxide fibers having a diameter of less than 5 microns. The apparatus comprises a hollow rotatable disc having about 0.3 to about 1.5 millimeter holes in its circumferential edge; means for rotatably mounting the disc; means for introducing a solution of a ceramic oxide precursor into the disc; means for rotating the disc to force solution through the openings in fiber form; means for attenuating the fibers with a stream of air; and means for calcining the fibers.

Abstract: Improved .gamma.-alumina suitable for use as a catalyst carrier having high mechanical strength, a large specific surface area, and a substantially uniform pore size distribution in a relatively small portion of the pore size range below 500 A. Said alumina is produced by first establishing a seed aluminum hydroxide hydrogel having a pH of between 6 and 10 and then repetitively and sequentially adding an aluminum compound to adjust the pH to less than 5 or more than 11 to dissolve crystallites of aluminum hydroxide followed by addition of a neutralizing agent to return the hydrogel to the pH range from about 6 to 10 to cause pseudo-boehmite crystallites to grow. After a sufficient number of repetitions of said sequential addition, sparse aggregates of crystallites of the desired structure are formed. These are dried and calcined to produce the said alumina.

Abstract: Disclosed is an alumina substrate having a high density, a high degree of surface smoothness and excellent dielectric properties and a process for its manufacture. The process comprises prefiring a green sheet prepared from alumina powder at an elevated temperature, for example between 1200.degree. and 1350.degree. C., to remove combustible substances from the sheet, treating the resultant prefired substrate with an acid aqueous solution to eliminate acid-soluble and decomposable substances from the substrate, and firing the acid-treated substrate at an elevated temperature, for example between 1500.degree. and 1650.degree. C.

Abstract: A process for producing alumina sols characterized by neutralizing a water-soluble basic aluminium salt of the formula,Al.sub.2 (OH).sub.x X.sub.y Y.sub.zwherein X is Cl or NO.sub.3, Y is SO.sub.4, and x, y and z are numbers satisfying the equations, x+y+2z=6, 0<x<6, 0.ltoreq.y<6, 0.ltoreq.2z<6, provided that y and z are not zero at the same time, with an alkali to produce alumina gels, and the subjecting said alumina gels to a hydrothermal treatment in the presence of a monovalent organic acid of such an amount that the molar ratio of the organic acid to aluminium is from 0.001 to 0.15.The alumina sols of the present invention are low in viscosity, high in Al.sub.2 O.sub.3 content and are extremely superior in stability with the lapse of time, and produce alumina powders superior in re-dispersibility.

Abstract: Alumina spheres having high crush strength are produced by hydrogelling low viscosity acidified alumina slurries in a surfactant-containing ammonia solution, said slurries being inserted into the ammonia solution dropwise.

Abstract: Alumina slurries are stabilized to prevent thickening and gelling by digesting dried alumina powder in hot water for a time sufficient to stabilize the alumina. The digested alumina is then recovered and dispersed in water containing a small amount of peptizing agent. The slurries so prepared have a low rate of thickening and gelling time is greatly extended.

Abstract: A method for preparing an alumina having controlled pore volume distribution is disclosed. The method requires the presence of 0.1-15% by weight of a water soluble aliphatic polycarboxylic acid having from 2-12 carbon atoms based on the dry weight of Al.sub.2 O.sub.3, during alumina precipitation. The resultant calcined alumina has a pore volume distribution such that:A. Nitrogen desorption measurements indicate that less than 10% of the total pores as determined by said method fall between 100-1200A in diameter;B. Nitrogen adsorption measurements indicate that between 10-50% of the total pore volume as determined fall between 100-1200A in diameter; andC. Mercury penetration porisimetry indicates that less than 10% of the total pores as determined by both nitrogen desorption and mercury methods fall between 100-50,000A in diameter.

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: Inexpensive hydrates of alumina are used for the production of dense, submicron alumina bodies by conversion of the alumina hydrates to a soluble form which is then used to produce a boehmite gel. The boehmite gel, with very small particles of alpha alumina intimately dispersed therein is dried and fired to 1300.degree. C. to 1450.degree. C.