Abstract: The invention relates to basic chromium aluminum sulfates which are soluble in cold water and are of the general formulaCr.sub.x Al.sub.2-x (OH).sub.2 y. (SO.sub.4).sub.3-y.n H.sub.2 Owhere x is from 0.1 to 1.9, y is from 0.01 to 2 and n is from 4 to 24, and a process for the preparation thereof. The process comprises reacting chromium (III)--containing waste sulfuric acid having a water content of 20-50% by weight with aluminum oxide and/or aluminum oxide hydroxide and/or aluminum hydroxide at a temperature of 100.degree. to 200.degree. C. The molten product is converted to droplet form and allowed to solidify in free fall.

Abstract: A beta and beta"-alumina precursor sol is prepared by controlled hydrolysis of chelated aluminum alkoxide in an alcohol solvent and, subsequently reacting it with a mixture of sodium, magnesium, and lithium alkoxides or acetates or a mixture thereof. The sol thus obtained can be converted into an amorphous transparent gel at low temperatures. This amorphous gel, crystallizes directly into crystalline beta-aluminas at about 1020.degree. C. On heating to about this temperature, crystalline beta and beta"-alumina are formed which are useful as solid electrolyte material in making a sodium-sulfur battery.

Abstract: To provide a lithium-containing neutron target particle for breeding tritium within the core of a nuclear reactor, including a central core formed of a stable lithium-containing compound, a surrounding buffer layer, and an outer tritium-impermeable silicon carbide coating, the core is initially sealed with an inner sealing layer of pyrolytic carbon and an outer sealing layer of stoichiometric zirconium carbide. The pyrocarbon seal protects the lithium within the core from attack from the zirconium carbide coating atmosphere, and the zirconium carbide layer prevents loss of lithium from the core when the silicon carbide coating is deposited at elevated temperatures.

Abstract: Crystalline transition metal aluminate compounds are formed by reacting transition metal compounds with crystalline hydrous alumina, such as gibbsite, bayerite, norstrandite, boehmite and the like. The crystalline hydrous alumina may be unsupported by a solid substrate or may be supported on a solid substrate or within the pores of a solid substrate, such as a macroporous resin.

Abstract: A depot fertilizer composition comprising an inorganic matrix and another inorganic and/or organic component of the formulaX Me(II)O.[(1-x)/2]Me(III).sub.2 O.sub.3.YA.zI.aqin whichMe (II) is at least one divalent metal,Me(III) is at least one trivalent metal,A is at least one inorganic acid or anhydride of an inorganic acid,I is at least one organic compound,aq is 0-9,X is from 0 to 1,Y is from 0.5 to 0.7, andZ is from 0 to 20,at least one of the components containing a plant nutrient element. The compositions are suited for fertilizing the leaves or full systems of plants growing in soil or in water.

Abstract: A process is disclosed for preparing impermeable, polycrystalline samples of Pb-.beta."-alumina ceramic from Na-.beta."-alumina ceramic by ion exchange. The process comprises two steps. The first step is a high-temperature vapor phase exchange of Na by K, followed by substitution of Pb for K by immersing the sample in a molten Pb salt bath. The result is a polycrystalline Pb-.beta."-alumina ceramic that is substantially crack-free.

Abstract: The disclosed polycrystalline transparent sintered body contains Al.sub.2 O.sub.3 and MgO at a molar ratio of (0.54:0.46) to (0.58:0.42) and has in-line transmittance of more than 77% for 1 mm thickness at a light wavelength of 0.6 .mu.m, which sintered body is produced by preparing fine spinel powder through hydrolysis of an isopropanol solution of aluminum isopropoxide and magnesium isopropoxide, forming a shaped body from the powder, and sintering the shaped body.

Abstract: Wet oxidation of organic contaminants in aqueous sodium aluminate solutions is enhanced when a heated and oxygenated solution is passed through a packed bed containing a metal packing member that is chemically inert to sodium aluminate solutions at elevated temperatures. Process temperature is about 180.degree.-300.degree. C. and oxygen partial pressure is at least about 345 kPa. The packed bed has a packing surface of at least 100 square meters per cubic meter bed volume and preferably at least 50% free space.

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: A process for producing basic aluminum magnesium carbonate, Al.sub.2 Mg.sub.6 (OH).sub.14 (CO.sub.3).sub.2.4H.sub.2 O, by carbonating an aluminum hydroxide (Al(OH).sub.3) and magnesium hydroxide aqueous reaction mixture with carbon dioxide in the presence of at least 6 moles of a base selected from the group consisting of ammonia, mono, di or trialkylamines, pyridine or piperidine, per mole of Al.sub.2 O.sub.3 present. The product is useful as an antacid.

Abstract: The disclosed polycrystalline transparent sintered body contains Al.sub.2 O.sub.3 and MgO at a molar ratio of (0.54:0.46) to (0.58:0.42) and has an in-line transmittance of more than 77% for 1 mm thickness at a light wavelength of 0.6 .mu.m, which sintered body is produced by preparing fine spinel powder through hydrolysis of an isopropanol solution of aluminum isopropoxide and magnesium isopropoxide, forming a shaped body from the powder, and sintering the shaped body.

Abstract: Spinel fine powders having high purity suitable for raw materials for producing a dense and uniform spinel sintered body, are produced by hydrolyzing an alcohol solution of specifically defined magnesium alkoxides and aluminum alkoxides in a specific mixing ratio.

Abstract: Processes for the preparation of pure alumina powders or pure non-stoichiometric alumina-magnesia spinel powders starting with ammonium alum-based compositions which are dehydrated, the dehydration being carried out on dehydrated salts having a bulk density less than 0.2 kg/dm.sup.3 and wherein the dehydration is followed by a calcination with a heating schedule containing at least one intermediate stage at 750.degree. to 850.degree. C., the process of the invention permitting the reproducible production of such aluminas or spinels having specific surfaces of from 100 to 200 m.sup.2 /g and characterized by a very high homogeneity which guarantees a rigorously unimodal pore structure, such aluminas and spinels being useful in preparing isotopic enrichment barriers for gaseous diffusion, as well as metal polishes, catalysts, and catalyst supports.

Abstract: Molten alkaline earth metal halides are used to convert highly stable oxides into the corresponding anhydrous halides. Usually a third reactant, such as silica, is added in order to bind the basic oxide thus formed. The solid oxide compounds (e.g. silicates) which result are wellknown ceramic phases of a high degree of purity.

Abstract: An improved process for the production of alkaline earth, aluminum-containing spinel compositions, preferably magnesium, aluminum-containing spinel compositions and at least one additional metal component, comprises combining alkaline earth metal, aluminum and additional metal components at selected pH conditions to form a precipitate and calcining the precipitate to form a spinel composition. The product spinel composition, is particularly suited for use to reduce the amount of sulfur oxides emitted from a catalyst regeneration zone, e.g., a catalytic cracking unit regeneration zone.

Abstract: A pharmaceutical composition comprising an amount, effective as an antacid, of a phosphate ion-containing hydrotalcite of the following formulaMg.sub.x Al.sub.2 (OH).sub.2x+6-n.sbsb.1.sub.z.sbsb.1.sub.-n.sbsb.2.sub.z.sbsb.2 (A.sub.1.sup.n.sbsp.1.spsp.-).sub.z.sbsb.1 (A.sub.2.sup.n.sbsp.2.spsp.-).sub.z.sbsb.2 .multidot.mH.sub.2 Owherein A.sub.1.sup.n.sbsp.1.spsp.- represents at least one anion having a valence of n.sub.1 selected from the group consisting of H.sub.2 PO.sub.4.sup.-, HPO.sub.4.sup.2.spsp.- and PO.sub.4.sup.-3, A.sub.2.sup.n.sbsp.2.spsp.- represents at least one anion having a valence of n.sub.2 other than the A.sub.1.sup.n.sbsp.1.spsp.-, and x, z.sub.1, z.sub.2, and m are positive numbers satisfying the following expressions2<x<40,0.05.ltoreq.z.sub.1 .ltoreq.2,0.1.ltoreq.z.sub.2 <2,0<m<40,0.5.ltoreq.z.sub.1 +z.sub.2 .ltoreq.

Abstract: A fired ceramics compact for use in casting of a super alloy material consisting of a solid solution of BaO and Al.sub.2 O.sub.3 wherein the composition of the solid solution lies on or between a first and a second eutectic composition, the first and the second eutectic compositions being adjacent and occurring to either respective side of stoichiometric BaO.Al.sub.2 O.sub.3 in a phase diagram of the solid solution.

Abstract: An improved process for the production of alkaline earth, aluminum-containing spinel compositions, preferably magnesium, aluminum-containing spinel compositions and preferably further comprising at least one additional metal component, comprises combining an acidic aqueous solution and a basic aqueous solution containing an aluminum component to form a combined mass; combining the combined mass with an aqueous solution containing at least one alkaline earth metal to form a precipitate; and calcining the precipitate to form a spinel composition. The product spinel composition, preferably with included additional metal components, is particularly suited for use to reduce the amount of sulfur oxides emitted from a catalyst regeneration zone, e.g., a catalytic cracking unit regeneration zone.

Abstract: A gel suitable for fiber formation is produced by reacting a Group II water soluble metal oxide with an aluminum chlorohydrate-organic complex to form a complex which is hydrolyzed and dried at elevated temperatures.

Abstract: An improved process for the production of alkaline earth, aluminum-containing spinel compositions, preferably magnesium, aluminum-containing spinel compositions and preferably further comprising at least one additional metal component, comprises combining alkaline earth metal and aluminum components at selected pH conditions to form a precipitate and calcining the precipitate to form a spinel composition. The product spinel composition, preferably with included additional metal components, is particularly suited for use to reduce the amount of sulfur oxides emitted from a catalyst regeneration zone, e.g., a catalytic cracking unit regeneration zone.

Abstract: An improved process for the production of alkaline earth, aluminum-containing spinel compositions, preferably magnesium, aluminum-containing spinel compositions and preferably further comprising at least one additional metal component, comprises adding a basic aqueous solution containing at least one aluminum component to an aqueous solution containing at least one alkaline earth metal component to form a precipitate at defined pH conditions and calcining the precipitate to form a spinel composition. The product spinel composition, preferably with included additional metal components, is particularly suited for use to reduce the amount of sulfur oxides emitted from a catalyst regeneration zone, e.g., a catalytic cracking unit regeneration zone.

Abstract: Cesium is recovered from cesium alum, CsAl(SO.sub.4).sub.2, by a two-reaction sequence in which the cesium alum is first dissolved in an aqueous hydroxide solution to form cesium alum hydroxide, CsAl(OH).sub.3, and potassium sulfate, K.sub.2 SO.sub.4. Part of the K.sub.2 SO.sub.4 precipitates and is separated from the supernatant solution. In the second reaction, a water-soluble permanganate, such as potassium permanganate, KMnO.sub.4, is added to the supernatant. This reaction forms a precipitate of cesium permanganate, CsMnO.sub.4. This precipitate may be separated from the residual solution to obtain cesium permanganate of high purity, which can be sold as a product or converted into other cesium compounds.

Abstract: The specification discloses new and improved processes for forming water-free metal or non-metal oxide materials, which may then be melted and formed into optical components in vitreous or crystal form, which are free of the hydrogen-impurity absorption in the near infrared wavelength range. In one process, a water-free oxide is prepared by reacting a chosen nonpolar compound containing the desired metal or non-metal with an aprotic oxygen-containing compound to form the oxide as a precipitate in a chosen aprotic nonaqueous liquid solvent which provides a water-free environment during the formation of the oxide, to prevent the inclusion of water and water-derived impurities in the oxide as formed.

Abstract: The specification discloses a process for forming a water-free rare earth oxychloride powder by exposing a water-containing rare earth oxide powder to a reactive atmosphere of chlorine and oxygen at 1000.degree. C. for 24 hours to remove water impurities from the oxide powder and to simultaneously convert the oxide powder to the oxychloride powder.

Abstract: The specification discloses new and improved processes for forming water-free metal or non-metal oxide materials, which may then be melted and formed into optical components in vitreous or crystal form, which are free of the hydrogen-impurity absorption in the near infrared wavelength range. In one process a water-free oxide is prepared by reacting a chosen organic compound containing oxygen bonded to an atom of the metal or non-metal, with a chosen organic acid anhydride to form an intermediate product which is then decomposed to form the desired oxide and to simultaneously regenerate the organic acid anhydride. The regenerated organic acid anhydride reacts with and removes traces of water and water-derived impurities during the formation of the desired oxide and prevents the inclusion of these impurities in the oxide as formed.

Abstract: Compositions conforming to the formula A.sub.x.sup.++ B.sub.y.sup.+++ (OH).sub.2x+3y-nz D.sub.z.sup.n-.tH.sub.2 O wherein A is a divalent metal, B is a trivalent metal, D is a polyanion, x, y, z and t are numbers greater than zero and n is a whole number preferably from 1 to 10 and the ratio of x:y is equal to or greater than 0.5 and less than or equal to 10 and a method for preparing said compositions are described.

Abstract: Spherical particles of lithium aluminate are formed by initially producing aluminum hydroxide spheroids, and immersing the spheroids in a lithium ion-containing solution to infuse lithium ions into the spheroids. The lithium-infused spheroids are rinsed to remove excess lithium ion from the surface, and the rinsed spheroids are soaked for a period of time in a liquid medium to remove water and NH.sub.4 OH from their surfaces. The soaked spheroids are then dried and sintered to form lithium aluminate spherical particles.

Abstract: Several methods are set forth for preparing polymetallic spinels by coprecipitating two or more metal compounds in a proportion to provide a total of eight positive valences when combined in the oxide form in the spinel crystal lattice. The methods disclosed require coprecipitation of the metals in the hydroxide form or convertible to the hydroxide-oxide form, calcining the coprecipitate, and finally sintering the calcined material at about one-half its melting point or greater, thereby forming a spinel which has a density of greater than 50 percent of the theoretical density of spinel crystal. Also disclosed are techniques for preparing spinels having more than two metals incorporated into the spinel lattice, as well as a separate oxide phase associated with the spinel crystallites, and slipcasting compositions.

Abstract: Crystalline transition metal aluminates conforming generally to the formulaMA.sub.a.sup.v Z.sub.b.sup.v.nAl(OH).sub.3.mH.sub.2 Owhere M is a transition metal having a valence charge of +2 selected from the group consisting of Cu, Zn, Mn, Fe, Co, and Ni, where AZ represents negative valence ions or radicals, v is a negative valence of 1, 2, or 3, n is a value to provide a mol ratio of Al/M of at least 1/1, preferably at least 1.5/1, and m is an integer of from zero to the maximum for waters of hydration, with (va)+(vb) equal to 2, are prepared in alkaline aqueous medium wherein transition metal compounds are caused to form adducts with amorphous hydrous alumina, Al(OH).sub.3, said adducts forming crystals when heated, said aluminates being useful, e.g., as ion exchangers and as spinel precursors among other things.

Abstract: Preparations and uses are shown for novel crystalline aluminates which conform generally to the empirical formulaMgA.sub.a.sup.v Z.sub.b.sup.v.nAl(OH).sub.3.mH.sub.2 Owhere A and Z represent negative-valence ions or radicals selected from the group comprising hydroxyl, halide, inorganic acid, and organic acid,n is a value of from about 1 to about 2,v is a negative valence of 1, 2, or 3,a and b each have values of from zero to 2,with (va)+(vb) equal to 2, andwith m being a value of zero or more.

Abstract: Flue gas having a content of sulfur dioxide is passed upwardly through a scrubbing tower against a descending flow of recycled aqueous sodium aluminate-sodium hydroxide liquor. The sulfur dioxide in the gas is converted to sodium and aluminum sulfates and sulfites and the liquor removes any fly ash present in the gas. Underflow is continuously discharged from the tower and is sent to an evaporator for removal of excess water. Make-up solutions of sodium sulfate and aluminum sulfate are added, as necessary. Carbonaceous reducing agent is added to the discharge from the evaporator. The mixture is continuously fed into a reducing furnace where the sulfates and sulfites are reduced to sulfides. The product of the furnace (molten sodium and aluminum sulfides) is charged into a continuous hydrolyzer. Hydrogen sulfide is evolved and collected, and, if desired, its sulfur content is converted to elementary sulfur. The underflow from the hydrolyzer is filtered.

Abstract: Process for preparing high purity aluminas from ammonium alum, the process comprising separately dehydrating the alum and thereafter thermally decomposing the dehydrate, wherein the thermal decomposition is carried out by forcing a gas through a layer of the dehydrated alum so as to continuously remove the gaseous reaction products formed without removal of solids by the carrier gas, and providing improved productivity of high purity transition aluminas having specific surfaces above 125 m.sup.2 /g and/or bulk densities above 0.2 g/cm.sup.3, the transition aluminas so obtained being characterized by their greater reactivity for the preparation of corundum so that corundum having a bulk density greater than 0.4 g/cm.sup.3 can be economically prepared.

Abstract: New intercalated compounds comprising a cation intercalated in a layered mixed oxide, said oxide having layers of corner linked octahedra and tetrahedra. The composition has the formula A.sub.q MOXO.sub.4.nH.sub.2 O where A is a monovalent, divalent or polyvalent cation, MOXO.sub.4 is a layered mixed oxide selected from the group consisting of VOPO.sub.4, VOSO.sub.4, VOAsO.sub.4, VOMoO.sub.4, NbOPO.sub.4, NbOAsO.sub.4, TaOPO.sub.4 and MoOPO.sub.4, n is a number from 0 to 4 and q is a number from about 0.001 to about 1.0.

Abstract: This invention is a new process for producing refractory crystalline oxides having improved or unusual properties. The process comprises the steps of forming a doped-metal crystal of the oxide; exposing the doped crystal in a bomb to a reducing atmosphere at superatmospheric pressure and a temperature effecting precipitation of the dopant metal in the crystal lattice of the oxide but insufficient to effect net diffusion of the metal out of the lattice; and then cooling the crystal. Preferably, the cooling step is effected by quenching. The process forms colloidal precipitates of the metal in the oxide lattice. The process may be used, for example, to produce thermally stable black MgO crystalline bodies containing magnetic colloidal precipitates consisting of about 99% Ni. The Ni-containing bodies are solar-selective absorbers, having a room-temperature absorptivity of about 0.96 over virtually all of the solar-energy spectrum and exhibiting an absorption edge in the region of 2 .mu.m.

Abstract: Lustrous flaky red iron oxide pigments containing aluminum in solid solution are produced by applying hydrothermal treatment to iron oxyhydroxide or colloidal precipitates of a ferric hydroxide in an aqueous aluminate solution. Lustrous pigments exhibiting various colors different from those of titanium dioxide-coated mica pigments are produced by coating titanium dioxide hydrate or titanium dioxide on the surface of the grains of flaky red iron.

Abstract: A new zeolite material designated Nu-3 having a molar composition expressed by the formula:0.5 to 1.5R.sub.2 O:Y.sub.2 O.sub.3 :at least 5XO.sub.2 :0 to 400H.sub.2 Owherein R is a monovalent cation or 1/n of a cation of valency n where n is a whole number of 2 or more, X is silicon and/or germanium, Y is one or more of aluminium, iron or gallium and H.sub.2 O is water of hydration additional to water notionally present when R is H, and having an X-ray diffraction pattern substantially as shown in Table 1, is prepared from a reaction mixture containing XO.sub.2 (preferably silica), Y.sub.2 O.sub.3 (preferably alumina) and an optionally substituted quinuclidinium ion.

Abstract: A strong zinc aluminate is prepared by first wetting a particulate alumina hydrate with a dilute acid to form a paste. Particulate zinc oxide is then added to the resulting paste. The mixture of alumina hydrate and zinc oxide is then dried and calcined to form zinc aluminate.

Abstract: A process for obtaining solid alkali metal aluminates from an alkali metal aluminate aqueous solution by spray drying an alkali metal aluminate aqueous solution having an alkali metal oxide concentration of 1 to 6 mols per liter and an alkali metal oxide to alumina molar ratio of greater than 1. Also disclosed is an apparatus employed for effecting spray drying in which a spray drier of unidirectional flow is employed whose longitudinal axis is substantially horizontally disposed.

Abstract: Alkali metal and ammonium dawsonites can be prepared by a non-aqueous process according to which equimolar quantities of the corresponding hydrogen carbonate and aluminum hydroxide in finely divided state are heated together to a temperature within the range of 150.degree. to 250.degree. C. for a period of 1 to 6 hours under a carbon dioxide pressure within the range of 120 to 360 psig. Carbonates may be used instead of hydrogencarbonates.

Abstract: A method of producing mineral fillers containing hydrated calcium monocarboaluminate.Al(OH).sub.3, CaCO.sub.3 and Ca(OH).sub.2 are reacted together in the presence of water, the operating temperature range being of 50.degree. C.-100.degree. C. Although these materials are insoluble, a quick reaction occurs as well in a highly concentrated solid medium as in a diluted medium. According to a preferred embodiment, the amount of water is such to obtain a final dry matter content of 50%, and the substantially solid resulting paste is directly brought to the fluidity required for use by means of a defloculating agent.Application to paper coating.

Abstract: Fibrous hydrotalcites having a hexagonal needle-like crystal structure. The fibrous hydrotalcites are produced by contacting a basic magnesium compound having a needle-like crystal structure and expressed by the following formula (2)Mg(OH).sub.2-n'x.sbsb.2 A.sub.x.sbsb.2.sup.n'.spsp.-.m.sub.2 H.sub.2 O (2)wherein A.sup.n'.spsp.- represents a monovalent or divalent anion, n' is 1 or 2, and x.sub.2 and m.sub.2 are numbers satisfying the following conditions,0.2.ltoreq.x.sub.2 .ltoreq.0.5,O.ltoreq.m.sub.2 .ltoreq.2,with a compound capable of providing a trivalent metal cation and being soluble in a liquid reaction medium which is chemically inert and is a non-solvent for the basic magnesium compound, the contacting being carried out in said liquid reaction medium under conditions which do not cause a loss of the needle-like crystal form of the basic magnesium compound, while maintaining the ratio of M.sup.3+ to the sum of Mg and M.sup.3+ at O<M.sup.3+ /(Mg+M.sup.3+).ltoreq.0.

Abstract: Crystalline transition metal aluminates conforming generally to the formulaMA.sub.a.sup.v Z.sub.b.sup.v.nAl(OH).sub.3.mH.sub.2 Owhere M is a transition metal having a valence charge of +2 selected from the group consisting of Cu, Zn, Mn, Fe, Co, and Ni, where AZ represents negative valence ions or radicals, v is a negative valence of 1, 2, or 3, n is a value to provide a mol ratio of Al/M of at least 1/1, preferably at least 1.5/1, and m is an integer of from zero to the maximum for waters of hydration, with (va)+(vb) equal to 2, are prepared in alkaline aqueous medium wherein transition metal compounds are caused to form adducts with amorphous hydrous alumina, Al(OH).sub.3, said adducts forming crystals when heated, said aluminates being useful, e.g., as ion exchangers and as spinel precursors among other things.

Abstract: A method and apparatus for outgassing raw materials includes the steps of and means for heating the material to a temperature of about 800.degree. C. and maintaining that temperature for a first bake out period during which the material is maintained at a pressure of about 200 millitorr and for a second bake out period during which the material is maintained at a pressure of about 5 millitorr or less. During the first bake out period, an inert gas is backstreamed through the raw material.

Abstract: The invention provides inorganic fibers based on calcium sulfate dihydrate or calcium sulfate aluminate hydrate (or their dehydration products), wherein the ratio of average length to diameter of the fibers is more than 100:1 and the length of the fibers is at least 0.2 mm; preferably the ratio of average length to diameter is 300-800:1, and the length is 0.5-6 mm.

Abstract: In a method of preparing a luminescent aluminate comprising aluminium and one or more of the metals yttrium and elements of the lanthanum series the component metals of the aluminate are co-precipitated from aqueous solutions of salts of these metals by combining these salts with a precipitation agent comprising carbon dioxide and ammonia in a quantity from 1 to 3 mole per mole of carbon dioxide. Such a quantity of the precipitation agent is used that the molar ratio of the carbon in the precipitation agent to the sum of the metals in the salts has a value from 1 to 10, a higher value in that range being chosen for this ratio according as the desired average grain size of the precipitate is larger. Finally, the precipitate obtained is heated at an elevated temperature.

Abstract: Impurities such as organic substances, i.e. sodium oxalate and inorganic impurities, i.e.

Abstract: A process for the production of sodium aluminate comprising drying an aluminate solution containing from 45 to 350 g/l of caustic Na.sub.2 O with a molecular ratio of caustic Na.sub.2 O to Al.sub.2 O.sub.3 from 1.1 to 1.8 in a fluidized bed of solid particles at 250.degree.-400.degree. C. of sodium aluminate using a gas heated to 750.degree.-950.degree. C. containing no carbon dioxide as a fluidizing medium and a heat carrier in an amount from 2000 to 25000 nm.sup.3 per 1 m.sup.3 of aluminate solution; feeding said aluminate, solution for drying by atomizing it at a velocity from 25 to 35 m/s thereby obtaining sodium aluminate in the form of pellets of a size from 0.5 to 8 mm with a bulk weight from 1.2 to 1.4 t/m.sup.3 completely soluble in water and alkaline solutions, with a maximum content of hygroscopic moisture of 0.3% by weight and a maximum content of water of crystallization of 5% by weight.

Abstract: The instant invention is related to the production of porous spinel materials which exhibit exceptional durability in both acid and basic solutions, and possess high porosity with high surface area and narrow range of pore size. More specifically, the present invention is directed to the production of porous spinel materials involving the impregnation of finely-divided trivalent metal oxides, usually Al.sub.2 O.sub.3, Fe.sub.2 O.sub.3, or Cr.sub.2 O.sub.3, with a solution of a divalent metal ion-containing compound, commonly selected from the group of Mg.sup.+2, Fe.sup.+2, Mn.sup.+2, and Zn.sup.+2, and thereafter firing the mixture to effect reaction, resulting in the conversion of the trivalent metal oxide to a spinel.

Abstract: A mixture containing 65 to 72% by weight of aluminum oxide and 28 to 35% by weight of magnesium oxide is used to mold items which are then dried in vacuum at a temperature of a heater, which is a component element of a mold, attaining about 1000.degree. C., the items being subsequently subjected to a burn in an inert gas atmosphere at a temperature of approximately 1850.degree. C. and at a rate of more than 100.degree. C./minute.The present invention permits the time required to manufacture the items to be brought down to 2-4 hours, the items produced being characterized by a high refractoriness, capable of withstanding temperatures of up to 1850.degree. C., high chemical inertness and resistance to dynamic action of refractory alloys and steels during melting and casting thereof. Thermal shock resistance of the manufactured items is 60 to 70 air thermal (heating-cooling) cycles.

Abstract: This disclosure deals with ettringite whiskers, methods of synthesizing such whiskers and ettringite whisker composites. The ettringite whiskers, having a new crystal form, are 1-2 .mu.m in diameter, 50-100 .mu.m in length and approximately 30-50 of aspect ratio. The ettringite whiskers are especially useful in industry as a high tensile strength reinforcement, they increase self-extinguishability and the productive capacity of making sheets, boards of the like.