Abstract: Rare earth element containing catalysts for dehydrogenating paraffins and the methods of making the catalysts are disclosed. A rare earth modified alumina support in eta-alumina form, theta-alumina form, or combinations thereof is impregnated with chromium-containing solution. The chromium-impregnated support is then subjected to calcination processes. The produced catalyst contains the rare earth element, chromium, and alumina. The crush strength of the produced catalyst is greater than 0.4 daN/mm.

Abstract: Rare earth element containing catalysts for dehydrogenating paraffins and the methods of making the catalysts are disclosed. A rare earth modified alumina support in eta-alumina form, theta-alumina form, or combinations thereof is impregnated with chromium-containing solution. The chromium-impregnated support is then subjected to calcination processes. The produced catalyst contains the rare earth element, chromium, and alumina. The crush strength of the produced catalyst is greater than 0.4 daN/mm.

Abstract: The present disclosure provides a transparent alumina-based plate, and a hot-pressing method to make the transparent alumina-based plate from platelet alumina. Alumina powder with a platelet morphology was hot-pressed to transparency with pre-load pressures of about 0-8 MPa, maximum temperatures of about 1750-1825° C., maximum pressures of about 2.5-80 MPa, and isothermal hold times of 1-7 hours. A novel alumina-based plate has been prepared, wherein the plate has a thickness of 2-5 mm, an in-line transmission of at least 60-75% for a light with a wavelength range of 645-2500 nm, an in-line transmission variance of <15% over the wavelength range of 645-2500 nm, and a relative density of 99.00-99.95%.

Abstract: Ceramic foundry media is provided. The ceramic foundry media have a size of about 80 mesh to about 10 mesh, an average largest pore size of less than about 20 microns, and a surface roughness of less than about 4 microns. The ceramic foundry media are formed by drip casting. A slurry of finely divided particles is flowed through nozzles and formed into droplets under the influence of vibration. Uniform sized, smooth surface, spherical green particles are formed. The green particles are dried and sintered to form the foundry media.

Abstract: A microspherical fluid catalytic cracking (FCC) catalyst includes Y zeolite and a gamma-alumina.

Abstract: The present invention relates to a porous aluminum hydrate, to a process for preparing same and to the use of same as intermediate in the preparation of an alumina or of a mixed oxide based on aluminum, on cerium and on zirconium. The invention also relates to the alumina obtained from the aluminum hydrate.

Abstract: This invention provides supported catalysts comprising a carrier, phosphorus, at least one Group VI metal, at least one Group VIII metal, and a polymer. In the catalyst, the molar ratio of phosphorus to Group VI metal is about 1:1.5 to less than about 1:12, the molar ratio of the Group VI metal to the Group VIII metal is about 1:1 to about 5:1, and the polymer has a carbon backbone and comprises functional groups having at least one heteroatom. Also provided are a process for preparing such supported catalysts, as well as methods for hydrotreating, hydrodenitrogenation, and/or hydrodesulfurization, using supported catalysts.

Abstract: The present invention relates to the field of solid materials for the adsorption of lithium. In particular, the present invention relates to a new method for the preparation of a crystallized and shaped solid material, preferably in extruded form, of the formula (LiCl)x.2Al(OH)3,nH2O, wherein n is between 0.01 and 10, x is between 0.4 and 1, wherein it comprises a step a) of precipitation of boehmite under specific temperature and pH conditions, a step of bringing into contact the precipitate obtained with LiCl, at least one acid extrusion-kneading shaping step, wherein the method also comprises a final hydrothermal treatment step, all of which makes it possible to increase the lithium adsorption capacity, the adsorption kinetics, as well as the lithium/boron selectivity of the materials obtained with respect to the materials of the prior art, when it is used in a lithium extraction method of saline solutions.

Abstract: Provided is a method for producing a porous metal oxide. The method includes: preparing a slurry by mixing a metal source, a pore forming agent and an aqueous solvent; drying the slurry to obtain a metal oxide precursor; and sintering the metal oxide precursor to generate a porous metal oxide. The metal source is an organometallic compound or hydrolyzate thereof containing a metal that makes up the porous metal oxide; the pore forming agent is an inorganic compound that generates a gas by decomposing at a temperature equal to or lower than a temperature at which the metal oxide precursor is sintered; and the slurry is prepared using 50 parts by weight or more of the pore forming agent with respect to 100 parts by weight of the metal source.

Abstract: Process for hydrogenating at least one aromatic or polyaromatic compound contained in a hydrocarbon feedstock having a final boiling point of less than or equal to 650° C., said process being performed in the gas phase or in the liquid phase at a temperature of between 30 and 350° C., at a pressure of between 0.1 and 20 MPa, at a hydrogen/(aromatic compounds to be hydrogenated) mole ratio of between 0.1 and 10 and at an hourly space velocity (HSV) of between 0.05 and 50 h?1, in the presence of a catalyst comprising an active phase comprising nickel, said active phase not comprising any group VIB metal, and a support comprising an amorphous mesoporous alumina having a connectivity (Z) of greater than 2.7, the connectivity being determined from the nitrogen adsorption/desorption isotherms.

Abstract: This invention discloses a preparation method of a hydrocracking catalyst. According to the method, a new functional group is modified through chemical bonds on the surface of a traditionally prepared inorganic carrier, and a VIB group metal element and a VIIIB metal element are then loaded on the carrier to prepare the hydrocracking catalyst. The hydrocracking catalyst prepared according to the invention has a higher diesel liquid yield.

Abstract: The present invention relates to an olefin metathesis reaction catalyst where rhenium (Re) oxide or molybdenum (Mo) oxide is supported, as a catalyst main component, on a surface-modified mesoporous silica or mesoporous alumina support, and a preparation method therefor. The olefin metathesis reaction catalyst of the present invention allows highly efficient metathesis of long-chain unsaturated hydrocarbons having at least eight carbons at a low temperature of 150° C. or lower. The catalyst can be separated readily from reaction solution, regenerated at a low temperature of 400° C. or lower by removing toxins accumulated on it during the metathesis reaction, and used repeatedly in metathesis reaction many times, thereby being made good use in commercial olefin metathesis processes.

Abstract: A process for producing alumina, the process having a seeding phase and a precipitation phase. During the seeding phase a seed mixture is produced by adding an aluminium salt to an aqueous solution and then adding an alkaline metal aluminate to the mixture while maintaining the seed mixture at generally neutral pH. The precipitation phase produces precipitated alumina by simultaneously adding aluminium salt and alkaline metal aluminate to the seed mixture while maintaining a pH from 6.9 to 7.8. The recovered precipitated alumina has at least one, preferably all the following characteristics: i) a crystallite size of 33-42 Ang.: in the (120) diagonal plane (using XRD); ii) a crystallite d-spacing (020) of between 6.30-6.59 Ang.; iii) a high porosity with an average pore diameter of 115-166 Ang.; iv) a relatively low bulk density of 250-350 kg/m3; v) a surface area after calcination for 24 hours at 1100° C. of 60-80 m2/g; and vi) a pore volume after calcination for one hour at 1000° C. 0.8-1.1 m3/g.

Abstract: A microspherical fluid catalytic cracking catalyst includes zeolite, and alkali metal alkaline earth metal ion.

Abstract: A catalytic converter includes a catalyst. The catalyst includes a metal oxide support and platinum group metal (PGM) complexes atomically dispersed on the metal oxide support. The PGM complexes include a PGM species selected from the group consisting of an atom of a platinum group metal, a cluster including from 2 atoms to less than 10 atoms of the platinum group metal, a nanoparticle including 10 or more atoms of the platinum group metal, and combinations thereof. An alkali metal or an alkaline earth metal is bonded to the PGM species. The alkali or alkaline earth metal is part of a structure including oxygen atoms and hydrogen atoms. A barrier is disposed between a first PGM complex and a second PGM complex.

Abstract: A process for treating a carrier, or a precursor thereof, to at least partly remove impurities from the carrier, or the precursor thereof, comprising: contacting the carrier, or the precursor thereof, with a treatment solution comprising a salt in a concentration of at most 0.05 molar, wherein the salt comprises a cation and an anion, and wherein the cation is selected from ammonium, phosphonium, organic cations and combinations thereof, and wherein the anion is selected from organic anions, inorganic carboxylates, oxyanions of elements from Groups IIIA through VIIA of the Periodic Table of Elements, and combinations thereof; and separating at least part of the treatment solution from the carrier, or the precursor thereof.

Abstract: A method of hydroprocessing a heavy hydrocarbon feedstock using a hydroprocessing catalyst having specific properties making it effective in the hydroconversion of at least a portion of the heavy hydrocarbon feedstock to lighter hydrocarbons. The hydroprocessing catalyst comprises a Group VIB metal component (e.g., Cr, Mo, and W), a Group VIII metal component (e.g., Ni and Co) and, optionally, a potassium metal component that are supported on a support material comprising alumina. The alumina has novel physical properties that, in combination with the catalytic components, provide for the hydroprocessing catalyst. The hydroprocessing catalyst is particularly effective in the conversion of the heavy hydrocarbon feedstock. The alumina is characterized as having a high pore volume and a high surface area with a large proportion of the pore volume being present in the pores within a narrow pore diameter distribution about a narrowly defined range of median pore diameters.

Abstract: A method of surface modification of an alumina carrier. The method includes: 1) dissolving a soluble kazoe in deionized water to yield a kazoe aqueous solution; 2) submerging an alumina carrier in the kazoe aqueous solution and drying the alumina carrier in a vacuum environment; 3) placing the dried alumina carrier in a reactor, adding silicon tetrachloride and Grignard reagent dropwise to the reactor, sealing the reactor and heating it to a constant temperature, and maintaining the constant temperature for between 3 and 18 hours, where a volume ratio of the added silicon tetrachloride and the alumina carrier is between 0.5:1 and 5:1, the constant temperature is controlled to be between 160 and 350° C.; and 4) cooling the reactor, filtering, washing, and drying the alumina carrier in the vacuum environment.

Abstract: Provided are methods of making dehydrogenation catalyst supports containing bayerite and silica. Silica-stabilized alumina powder, prepared by spray drying of bayerite powder, precipitating silica in a bayerite slurry with an acid, or impregnation or co-extrusion of bayerite with sodium silicate solution was found to be a superior catalyst support precursor. Catalysts prepared with these silica containing support materials have higher hydrothermal stability than current CATOFIN® catalysts. Also provided is a dehydrogenation catalyst comprising Cr2O3, an alkali metal oxide, SiO2 and Al2O3, and methods of using said catalyst to make an olefin and/or dehydrogenate a dehydrogenatable hydrocarbon.

Abstract: A process for preparing a mesoporous metal oxide, i.e., transition metal oxide, Lanthanide metal oxide, a post-transition metal oxide and metalloid oxide. The process comprises providing an acidic mixture comprising a metal precursor, an interface modifier, a hydrotropic ion precursor, and a surfactant; and heating the acidic mixture at a temperature and for a period of time sufficient to form the mesoporous metal oxide. A mesoporous metal oxide prepared by the above process. A method of controlling nano-sized wall crystallinity and mesoporosity in mesoporous metal oxides. The method comprises providing an acidic mixture comprising a metal precursor, an interface modifier, a hydrotropic ion precursor, and a surfactant; and heating the acidic mixture at a temperature and for a period of time sufficient to control nano-sized wall crystallinity and mesoporosity in the mesoporous metal oxides. Mesoporous metal oxides and a method of tuning structural properties of mesoporous metal oxides.

Abstract: The present invention is a process for making an inorganic/organic hybrid totally porous spherical silica particles by self assembly of surfactants that serve as organic templates via pseudomorphic transformation.

Abstract: Silver based ethylene oxide catalysts having enhanced stability are disclosed. The enhanced stability silver based ethylene oxide catalysts include an alumina carrier which has been modified to include cavities on the surface of the carrier. The presence of the cavities on the surface of the modified carrier stops or at least impedes the motion of silver particles on the surface of the carrier during an epoxidation process. In particular, the cavities on the surface of the alumina carrier effectively trap and/or anchor silver particles and prevent them from further motion.

Abstract: A method for making a catalyst composition suitable for various purposes, such as the reduction of nitrogen oxides, is provided. The method includes combining dawsonite or a dawsonite derivative with a catalytic active element.

Abstract: Micelle-templated superficially porous particles having a solid core and an outer porous shell with ordered pore structures and a narrow particle size distribution, such as about ±5% (one sigma), and a high specific surface area of about 5 to about 1000 m2/g.

Abstract: A regenerating method for activated alumina used in regenerating working fluid of hydrogen peroxide comprises the following steps: adding deactivated alumina discharged from a regenerating bed for working fluid of hydrogen peroxide with fire resistant alumina into a reactor through the top of the reactor and settling by gravity, oxidizing atmosphere entering into the reactor from the bottom of the reactor and running upwardly, discharging regenerated alumina and fire resistant alumina through the discharging device on the bottom of the reactor, discharging exit gas through the discharge port on the top of the reactor, the reaction temperature ranging from 360-800° C., the residence time of solid feed in the reactor ranging from 3-15 h. The method is economic, environment-protective, safe, and low-costly. The regenerated alumina will not poison palladium catalyst.

Abstract: A regenerating method for activated alumina used in regenerating working fluid of hydrogen peroxide comprises the following steps: adding deactivated alumina discharged from a regenerating bed for working fluid of hydrogen peroxide into a reactor through the top of the reactor and settling by gravity, oxidizing atmosphere entering into the reactor from the bottom of the reactor and running upwardly, then discharging exit gas and regenerated alumina through the discharge port on the top and discharging device on the bottom of the reactor respectively. The method is economic, environment-protective, safe, low-costly. The regenerated alumina will not poison palladium catalyst.

Abstract: The invention relates to a substrate material, which is highly porous and which is provided with a mechanically stable, component-penetrating framework structure made of alpha-Al2O3, to methods for producing the substrate material, and to the use of the substrate material.

Abstract: The invention relates to a substrate material, which is highly porous and which is provided with a mechanically stable, component-penetrating framework structure made of alpha-Al2O3, to methods for producing the substrate material, and to the use of the substrate material.

Abstract: The invention relates to a method for preparing a chemical composition obtained by co-impregnating water-soluble salts Ba/Mg and phosphoric acid H3PO4 on boehmite alumina which has been calcined in the presence of water vapor. Said chemical composition is used as an additive in the catalytic cracking process in order to capture metals originating from the charge, particularly vanadium, in the presence of SO2 and thus to protect the activity and selectivity of the catalytic cracking catalyst.

Abstract: The invention relates to chemical compositions that can be used for hydrocarbon catalytic cracking processes with vanadium as a contaminant, including an active phase formed by different pyrophosphates M2P2O7 (M=Ba or Ca) supported on a mixture of magnesium and aluminum oxide, preferably magnesium aluminate in the spinel phase. The composition captures the metals originating from the charge, particularly vanadium, and thus protects the catalyst. Said composition is preferably used in the form of a separated particle in order to the control the addition thereof to the unit according to the metal content of the charge. The invention also relates to the method for preparing said composition, including synthesis of pyrophosphates, formation of a suspension of boehmite alumina, magnesium oxide or magnesium hydroxide, together with oxides M2P2O7, spray drying and calcination of the microspheres without generating any loss in the crystalline structure of oxides M2P2O7.

Abstract: A method for producing a densified fumed metal oxide having an increased bulk density and substantially the same surface area as an undensified fumed metal oxide with the same molecular composition is provided. The fumed metal oxide is wetted with a solvent to form a wetted fumed metal oxide. The wetted fumed metal oxide is dried to form a dried fumed metal oxide. The dried fumed metal oxide is calcined.

Abstract: A process for treating a carrier, or a precursor thereof, to at least partly remove impurities from the carrier, or the precursor thereof, comprising: contacting the carrier, or the precursor thereof, with a treatment solution comprising a salt in a concentration of at most 0.05 molar, wherein the salt comprises a cation and an anion, and wherein the cation is selected from ammonium, phosphonium, organic cations and combinations thereof, and wherein the anion is selected from organic anions, inorganic carboxylates, oxyanions of elements from Groups IIIA through VIIA of the Periodic Table of Elements, and combinations thereof; and separating at least part of the treatment solution from the carrier, or the precursor thereof.

Abstract: A process for preparing a mesoporous alumina is described, comprising the following steps: a) mixing, in aqueous solution, at least one source of aluminum constituted by an aluminum alkoxide, at least one cationic surfactant and at least one organic solvent selected from methanol and ethanol; b) hydrothermally treating the mixture formed in said step a); c) drying the solid formed in said step b); d) calcining the solid formed in said step c).

Abstract: Preparing porous particles includes forming a gel including a first liquid and an oxygen-containing compound of a metal, semi-metal, metalloid, or semi-conductor, including an oxide, hydroxide, alkoxide, oxohydroxide, oxoalkoxide, oxo salt, or oxo salt hydrate of the metal, semi-metal, metalloid, or semi-conductor; contacting the gel with a combustible liquid to form a combustible gel; and initiating combustion of the combustible gel to form a substance including porous metal, semi-metal, metalloid, or semi-conductor oxide particles. The combustible liquid can include a volatile solvent. The porous particles have open pores with a range of nanoscale pore sizes. The porous particles may be treated further to form, for example, a composite.

Abstract: A process for preparing aluminum oxide with a low calcium content, in which (1) crude alpha- and/or gamma-aluminum oxide with a total calcium content in the range from 50 to 2000 ppm, based on the crude alpha- and/or gamma-aluminum oxide, is mixed with an aqueous solution or suspension comprising the compounds selected from the group of inorganic acid, organic acid and complexing agent, (2) the mixture from step (1) is admixed with a flocculating aid, (3) in the mixture of step (2), the solids are separated from the liquid, (4) the solids separated are mixed with water in the presence or in the absence of a flocculating aid, (5) in the mixture of step (4), the solids are separated from the liquid, (6) optionally, steps (4) and (5) are repeated once or more than once, (7) optionally, the solids separated optionally after addition of further compounds, are dried.

Abstract: This invention relates to crystalline boehmitic aluminas the crystallites of which exhibit unusual dimensional differences in the space directions 020 and 120. This invention further relates to a method for preparing such aluminas and the follow-up products obtained therefrom by calcination.

Abstract: The present invention is a process for making an inorganic/organic hybrid totally porous spherical silica particles by self assembly of surfactants that serve as organic templates via pseudomorphic transformation.

Abstract: This invention relates to catalyst carriers to be used as supports for metal and metal oxide catalyst components of use in a variety of chemical reactions. More specifically, the invention provides a process of formulating a low surface area alpha alumina carrier that is suitable as a support for silver and the use of such catalyst in chemical reactions, especially the epoxidation of ethylene to ethylene oxide. A precursor for a catalyst support comprises an admixture of an alpha alumina and/or a transition alumina; a binder; and either a solid blowing agent which expands, or propels a gas upon the application of sufficient heat, and optionally contains talc and/or water soluble titanium compound.

Abstract: A process for the recovery of high purity boehmite with controlled pore size from spent hydroprocessing catalyst includes the step of treating the spent hydroprocessing catalyst composition in order to get recovery of the aluminas after extracting the valuable metals. The process permits easy and resourceful recovery of high quality boehmite from waste catalyst, which can be further used as hydroprocessing catalyst carrier having a pore structure almost identical or better than that used in heavy oil hydroprocessing catalysts. Such catalyst carrier is required to have high pore volume, macro-porosity, high strength and optimum surface area for active metal dispersion. The treating steps include process steps such as decoking, roasting, leaching, dissolving, digestion, precipitation, washing, stripping, and the like. The recovery steps include digestion, hydrothermal treatment, flocculation or precipitation, filtration, drying, calcination and the like.

Abstract: A process for preparing a mesoporous alumina is described, comprising the following steps: a) mixing, in aqueous solution, at least one source of aluminium constituted by an aluminium alkoxide, at least one cationic surfactant and at least one organic solvent selected from methanol and ethanol; b) hydrothermally treating the mixture formed in said step a); c) drying the solid formed in said step b); d) calcining the solid formed in said step c).

Abstract: Compositions for making alpha-alumina supports for, for example, inorganic membranes are described. Methods for controlling the alumina and pore former particle sizes and other process variables are described which facilitate desirable porosity, pore distribution and strength characteristics of the resulting alpha-alumina inorganic membrane supports.

Abstract: A crystallized solid, referred to by the name IM-14, which has an X-ray diffraction diagram as provided below, is described. Said solid has a chemical composition that is expressed according to the formula GeO2:nY2O3:pR:qF:wH2O, where R represents one or more organic radical(s), Y represents at least one trivalent element, and F is fluorine.

Abstract: Aluminum oxide powder in the form of aggregates of primary-particles, which has a BET surface area of from 10 to 90 m2/g and comprises as crystalline phases, in addition to gamma-aluminum oxide and/or theta-aluminum oxide, at least 30% of delta-aluminum oxide. It is prepared by vaporizing aluminum chloride and burning the vapor together with hydrogen and air, the ratio of primary air/secondary air being 0.01 to 2, the exit speed vB of the reaction mixture from the burner being at least 10 m/s, the lambda value being 1 to 4, the gamma value being 1 to 3 and the value of gamma*vB/lambda being greater than or equal to 55. Dispersion comprising the aluminum oxide powder. Coating composition comprising the dispersion.

Abstract: An aggregate material includes an aluminous material and a toughening agent in contact with the aluminous material. The aluminous material has a primary aspect ratio of at least about 1.5 and a particle size between about 30 nm and about 1000 nm.

Abstract: ?-Alumina powder having a purity of at least 99.99% by weight, a specific surface area of from 0.1 to 2.0 m2/g, a relative density of from 55 to 90%, and a closed porosity of 4% or less, wherein in a weight-based particle size distribution obtained by the dry sieving test according to JIS K0069 (1992), an amount of particles having a particle size of less than 75 ?m is 5% by weight or less; an amount of particles having a particle size exceeding 2.8 mm is 15% by weight or less; and at least one frequency maximum peak appears in a particle size range of 100 ?m or more and to less than 850 ?m. This ?-alumina powder can be charged in a crucible at a high bulk density, from which sapphire having a few voids can be produced without causing the oxidation of a crucible in a heat melting step.

Abstract: A composite material includes a polymer matrix and a particulate material dispersed within the polymer matrix. The particulate material includes metal oxide coated alumina hydrate. The particulate material has a 500 psi Compaction Volume Ratio of at least about 4.0 cc/cc. The metal oxide coating may include precipitated silica. The particulate material may have a Hg Cumulative Pore Volume of at least 1.65 cc/g.

Abstract: The present invention discloses an alumina support having multiple pore structure, wherein the alumina support has a specific surface area of from 40 to 160 m2/g and a total pore volume of from 0.3 to 1.2 cm3/g; a pore volume of pores having a pore diameter of less than 30 nm comprises 5 to 60% of the total pore volume; a pore volume of pores having a pore diameter of from 30 to 60 nm comprises 20 to 75% of the total pore volume; and a pore volume of pores having a pore diameter of larger than 60 nm comprises 20 to 60% of the total pore volume. The present invention further discloses a catalyst used for selective hydrogenation of a pyrolysis gasoline, comprising: (a) the alumina support according to the invention; and (b) 0.01 to 1.2 wt. % of metal palladium or palladium oxides, based on the weight of the alumina support.

Abstract: The present invention relates to a cobalt/phosphorus-alumina catalyst in which cobalt is supported as an active component on a phosphorus-alumina support wherein phosphorus is supported on alumina surface. With a bimodal pore structure of pores of relatively different pore sizes, the catalyst provides superior heat- and matter-transfer performance and excellent catalytic reactivity. Especially, when Fischer-Tropsch (F-T) reaction is performed using the catalyst, deactivation by the water produced during the F-T reaction is inhibited and, at the same time, the dispersion and reducing property of cobalt and other active component are improved. Therefore, the cobalt/phosphorus-alumina catalyst for F-T reaction in accordance with the present invention provides good carbon monoxide conversion and stable selectivity for liquid hydrocarbons.

Abstract: The present invention provides nanoporous ?-alumina powders comprising powder comprising interconnected ?-alumina primary particles having an average particle size of less than about 100 nm and an interpenetrated array of pores or voids. The invention also provides nanosized ?-alumina powders comprising ?-alumina particles having an average particle size of less than about 100 nm and slurries, particularly aqueous slurries, which comprise nanosized ?-alumina powders of the invention. The invention further provides methods of manufacturing nanoporous ?-alumina powders and nanosized ?-alumina powders of the invention and methods of polishing using slurries of the invention.

Abstract: A method for fabricating a high specific surface area mesoporous alumina is disclosed, which includes the following steps: (a) providing a water solution containing an aluminum salt and a fluoro-surfactant; (b) adding concentrated hydrochloric acid to adjust the PH value of the solution to about 6.0 to 8.0; (c) aging the solution at 70° C. to 110° C. for 12 to 20 hours; (d) washing the precipitate with water; (e) washing the precipitate with an organic solvent; (f) drying the precipitate; and (g) sintering the precipitate in a furnace of 500° C. to 1000° C.