Abstract: An improvement in a mixture for forming into a body that is to be fired into a “whiteware ceramic product” wherein the mixture is a compound of clay and other minerals with a ferric oxide content of less than about 5.0% by weight of the dry mixture. The improvement includes adding to the mixture a binder in the form of a combination of protein and a vegetable flour with an equivalent gram strength of at least 30 grams and a protein content of 20-50% of the binder, where the binder is in the range of 0.05% to 0.50% by weight of the dry mixture.

Abstract: A composition includes a sintered mass having a plurality of cores and a grain boundary layer disposed between each of the plurality of cores. The core includes a transition metal oxide, and grain boundary layer includes a sintering additive, a grain growth inhibitor additive and a grain boundary additive.

Abstract: A composite article includes a substrate and a layer attached to the substrate. The layer includes a metal phase, a first ceramic phase, and a second ceramic phase.

Abstract: A carbon dioxide gas absorbent includes a porous body containing a lithium complex oxide. The porous body includes pores having a pore diameter distribution such that main pores which consist of first pores with a diameter of 10 to 100 ?m and second pores with a diameter larger than 100 ?m and 500 ?m or smaller occupy 80 to 100%, third pores with a diameter smaller than 10 ?m occupy 0 to 10% and fourth pores with a diameter larger than 500 ?m occupy 0 to 10%, the main pores have a pore diameter distribution such that the first pores occupy 15 to 85% and second pores occupy 15 to 85%.

Abstract: This invention relates to an amorphous non-glassy ceramic composition that may be prepared by curing, calcining and/or pyrolyzing a precursor material comprising silicon, a Group III metal, a Group IVA metal, and/or a Group IVB metal.

Abstract: A vitreous antimicrobial agent that can exhibit excellent antimicrobial properties when added to various types of resins, that has excellent discoloration resistance and hot water resistance, and that can easily be produced at a commercial scale. The vitreous antimicrobial agent includes, relative to 100 mass % of total glass components, 0.1 to 2 mass % of Ag2O, 40.5 to 49 mass % of ZnO, 6 to 9.5 mass % of SiO2, 30.5 to 39.5 mass % of B2O3, 2 to 10 mass % of an alkaline earth metal oxide, and 6 to 7.5 mass % of Na2O; the vitreous antimicrobial agent comprising, in addition to these, 0.01 to 5 mass % of CeO2 as necessary. An antimicrobial resin composition and an antimicrobial product including the vitreous antimicrobial agent.

Abstract: A hydrogen storage material is expressed by a composition formula, (Ca1-xAx)1-z(Si1-yBy)z, wherein “A” is at least one member selected from the group consisting of alkali metal elements, alkaline-earth metal elements, rare-earth elements, the elements of groups 3 through 6, Ni, Au, In, Tl, Sn, Fe, Co, Cu and Ag; “B” is at least one member selected from the group consisting of the elements of groups 7 through 17, rare-earth elements, Hf and Be; 0?x<1 by atomic ratio; 0?y<1 by atomic ratio; and 0.38?z?0.58 by atomic ratio. It is lightweight as well as less expensive. In principle, neither high-temperature nor high-pressure activation is required, because it exhibits a high initial activity. The operation temperature can be lowered and the hydrogen absorption content can be enlarged by controlling the kind and substitution proportion of the substituent elements appropriately.

Abstract: There is provided a honeycomb structured body having improved durability in a honeycomb structure body obtained by unitarily bonding a plurality of honeycomb segments. There is provided a honeycomb structure body 1 including a plurality of honeycomb segments 12 each having an outer wall 7, partition walls 2 disposed in the outer wall 7, and a plurality of cells 3 separated from each other by the partition walls 2 and extending in an axial direction, a bonding layer 8 interposed between the plurality of honeycomb segments 12 to unitarily bond the honeycomb segments 12, and an intermediate layer 9 interposed between the bonding layer 8 and the honeycomb segments 9. In the honeycomb structure body 1, pores having a diameter of 0.5 ?m or more of the intermediate layer 9 occupies 25% by volume or less of the whole volume of the intermediate layer 9.

Abstract: A corrosion-resistant silicon nitride ceramics in which an adhesion enhancing layer (3), a stress relaxing layer (4) and a crack extension preventing layer (5) are laminated in this order on a ceramic substrate (2) composed mainly of silicon nitride, and a surface corrosion-resistant layer (6) composed mainly of zirconium oxide stabilized by an element of the group 3a of the periodic table is laminated. The thermal expansion coefficient (?0) of the ceramic substrate (2), the thermal expansion coefficient(?1) of the adhesion enhancing layer (3), and the thermal expansion coefficient (?2) of the stress relaxing layer (4), the thermal expansion coefficient (?3) of the crack extension preventing layer (5), and the thermal expansion coefficient (?4) of the surface corrosion-resistant layer (6) satisfy the following relational expressions (I) to (III): ?0??1??(I) ?3<?2??(II) ?3<?4??(III).

Abstract: The present invention is characterized in that a base material is coated with a ceramic thin film comprising a composite phase composed of a first phase mainly formed of a silicon ceramic component and a second phase mainly formed of a ceramic component other than the silicon ceramic component of the first phase, in which the amount of fine crystal particles of at least one ceramic component that constitutes the second phase slopingly increases toward a surface layer. According to the present invention, there are provided a ceramic thin film coating material having a slope constitution, which not only has an excellent function such as a photocatalyst function, an electrical function, a thermal catalyst function or a catalyst-supporting function or environment resistance such as oxidation resistance, alkaline resistance or wear resistance but also has excellent dynamic properties, and a process for the production thereof.

Abstract: A glass fiber composition comprises about 52-65 weight % SiO2; less than or equal to 4 weight % Al2O3; about 7-16 weight % Fe2O3; greater than 6 weight % and less than or equal to about 14 weight % R2O; about 6-25 weight % CaO; less than or equal to 10 weight % MgO; and about 10-25 weight % RO; wherein R2O represents alkali metal oxides and RO represents alkaline earth metal oxides. Preferably, the glass fiber composition has a liquidus temperature of less than 2350° F.; and a viscosity at a liquidus temperature of the glass fiber composition of greater than 500 poise; and fire resistant glass fiber formed from the glass fiber composition has a biodissolution rate of greater than 50 ng/cm2/hr.

Abstract: A preform for a composite material which has high strength and excellent air permeability and hence is applicable to a high-speed die casting method and which is capable of forming a metal composite material having excellent mechanical properties by a high-speed die casting method. Also provided is a process for producing such a preform. Ceramic fibers or/and ceramic particles are mixed with a silica sol and calcium carbonate and sintered at a predetermined temperature to form a calcium/silicon sinter obtained from the silica sol and calcium carbonate. The calcium/silicon sinter coats the ceramic fibers or/and ceramic particles so that a preform having the fibers or/and the particles bound to each other by the calcium/silicon sinter is obtained. The preform for a composite material has high strength and excellent air permeability and is applicable to the high-speed die casting method capable of attaining high productivity.

Abstract: Circuit modules and methods of construction thereof that contain composite meta-material dielectric bodies that have high effective values of real permittivity but which minimize reflective losses, through the use of host dielectric (organic or ceramic), materials having relative permittivities substantially less than ceramic dielectric inclusions embedded therein. The composite meta-material bodies permit reductions in physical lengths of electrically conducting elements such as antenna element(s) without adversely impacting radiation efficiency. The meta-material structure may additionally provide frequency band filtering functions that would normally be provided by other components typically found in an RF front-end.

Abstract: There is disclosed a honeycomb structure 1 which is made of a ceramic material and in which a plurality of honeycomb segments 12 having cell structures 5 and porous outer walls 7 on outer peripheries of the cell structures 5 are integrated by bonding the outer walls 7 to one another with a bonding material, each of the cell structures being provided with a plurality of cells 3 constituting fluid channels divided by porous partition walls 2, wherein the bonding material contains a bio-soluble fiber. The honeycomb structure 1 of the present invention has a performance equivalent to that of a honeycomb structure in which a heretofore used ceramic fiber is contained.

Abstract: The present invention relates to a method of producing coloured carrier particles which comprises which comprises: a) dispersing a pigment in aqueous solution, b) adding soda waterglass, c) precipitating SiO2 and the pigment onto the carrier particles by lowering the pH value. Using the methods according to the invention it is possible to obtain colorations and coloured substrates that have surprisingly good light-fastness properties.

Abstract: Aqueous dispersion containing: at least one metal oxide selected from the group consisting of alpha-aluminium oxide, cerium oxide, silicon dioxide, titanium dioxide and zirconium dioxide and in addition at least one transition aluminium oxide which is present in the form of aggregates of primary particles, wherein the total content of metal oxide and transition aluminium oxide is from 60 to 75% by weight, based on the total amount of the dispersion, the content of transition aluminium oxide is from 30 to 45% by weight, based on the total amount of the dispersion, the BET surface area of the transition aluminium oxide is from 30 to 90 m2/g, the mean aggregate diameter of the transition aluminium oxide is less than 100 nm, the mean particle diameter of the metal oxide is from 100 to 500 nm, and a dispersant selected from the group consisting of polyaluminium hydroxychloride, polyaluminium hydroxynitrate and/or polyaluminium hydroxysulphate.

Abstract: The invention relates to a method for the protection of openings in a component, produced from an electrically-conducting material, in particular, from metal or a metal alloy, during a machining process against the ingress of material, whereby the openings are sealed with a filler material before the machining process, which is removed again after the machining process. The machining processes particularly concern coating processes and welding processes. Said method is characterized in that an electrically-conducting filler material is applied, the electrical conductivity of which matches the electrical conductivity of the base material.

Abstract: Subjects for the invention are to obtain a quartz powder having a high purity and high quality and a process for producing the same and to obtain a glass molding formed by melting and molding the powder and extremely reduced in bubble inclusion. The invention provides a quartz powder, preferably a synthetic quartz powder obtained by the sol-gel method, which, upon heating from room temperature to 1,700° C., generates gases in which the amount of CO is 300 nl/g or smaller and the amount of CO2 is 30 nl/g or smaller.

Abstract: A method and a ceramic made therefrom by: providing a composition of a compound having the formula below and a metallic component, and pyrolyzing the composition. The value n is a positive integer. Q is an acetylenic repeat unit having an acetylene group, crosslinked acetylene group, (MLx)y-acetylene complex, and/or crosslinked (MLx)y-acetylene complex. M is a metal. L is a ligand. The values x and y are positive integers. The metallic component is the (MLx)y-acetylene complex in the compound or a metallic compound capable of reacting with the acetylenic repeat unit to form the (MLx)y-acetylene complex. The ceramic comprises metallic nanoparticles.

Abstract: A chemically bonded ceramic is formed by contacting a Wollastonite component and acid component to form a precursor, which precursor then cured to form the ceramic, with at least one of the components, or precursor cooled to increase the working pot life.

Abstract: A method for rigidifying a fiber-based paper substrate for use in the exhaust system of a combustion device. In the method, a green ceramic fiber-based paper substrate is impregnated with an impregnating dispersion. The impregnated substrate is then dried, calcined and fired to form a rigidified substrate that is suitable for use in the exhaust system of a combustion device. This rigidification process is performed at least once and, preferably, two or more times. The green paper substrate comprises two or more sheets of green ceramic fiber-based paper, with at least one creased sheet and another sheet being a laminated together to form a plurality of tubular channels. The rigidified substrate comprises refractory ceramic fibers in the form of a ceramic fiber-based paper and agglomerates of ceramic particles.

Abstract: A ceramic composition including a first ceramic material and a second ceramic material that is in the form of nano-, submicron-, or micron-sized particles, in which the first ceramic material has a lower melting point than the second ceramic material, and, when the first ceramic material melts into a liquid and the second ceramic material remains particulate, the second ceramic material floats at the top of the liquid. Also disclosed is a variant of this composition including a first ceramic material and a second ceramic material, in which the second ceramic material has a melting point higher than the first ceramic material, and, when the first ceramic material melts into a liquid, the second ceramic material partially or completely dissolves in the liquid.

Abstract: A composite material according to the present invention, is composed of SiC, SiO2, at least one out of Al and Si, with He leak rate of 1.3×10?10 Pa·m3/sec or below, thereby providing a composite material, which has a higher vacuum air-tightness, an excellent thermal conductivity, an adjustable coefficient of thermal expansion, small variation in strength and higher reliability, and a method for manufacturing the composite material, and a wafer holding member including the composite material.

Abstract: A modified sol-gel method to create metal-rich siliceous material, such as colloidal silica or aluminosilicate particles is disclosed. Initially, the metal salt of choice is added to a silicic acid solution or a silicic acid solution containing aluminum salt. The aluminum is added to vary the metal-support interaction as it forms Al—O—Si linkages within the silica matrix. Besides aluminum, other metals can be added that form M-O—Si (M=Ti, B, etc.) linkages, which do not become reduced when treated with a reducing agent. Once the metal, silicic acid and/or aluminum salt is generated, it is subjected to colloidal growth by addition to a basic heel. Upon colloidal synthesis, the metal salt containing colloidal particle is left as is to maximize colloidal stability or is reduced with hydrazine to produce the zero valence metal-containing colloidal particle.

Abstract: This disclosure relates to oxide materials, as well as related articles, systems and methods.

Abstract: A ceramic composite material is comprised of a fabric of fibers of an inorganic substance; and a matrix for combining the fibers. The matrix consists essentially of a ceramic. The matrix is formed by burying the fabric in a mixture of a powder of carbon, a powder of silicon and a medium including an organic solvent, producing an oscillation in the mixture to impregnate the fabric with the mixture, and calcining the fabric impregnated with the mixture.

Abstract: An electrode-forming composition and a plasma display panel manufactured using the electrode-forming composition are provided.

Abstract: Multiphase ceramic nanocomposites having at least three phases are disclosed. Each of the at least three phases has an average grain size less than about 100 nm. In one embodiment, the ceramic nanocomposite is substantially free of glassy grain boundary phases. In another embodiment, the multiphase ceramic nanocomposite is thermally stable up to a temperature of at least about 1500° C. Methods of making such multiphase ceramic nanocomposites are also disclosed.

Abstract: Glass-bonded ceramics made of non-microcracked non-oxide or oxide ceramic particles which are bound together by glass into a unitary non-microcracked structure are disclosed. Such ceramics are suitable for use in substrates and filters, such as a diesel particulate filter.

Abstract: A method of jet milling silicon powder in which silicon pellets are fed into a jet mill producing a gas vortex in which the pellets are entrained and pulverized by collisions with each other or walls of the milling chamber. The chamber walls are advantageously formed of high-purity silicon as are other parts contacting the unground pellets or ground powder. The pellets and chamber parts may be formed of electronic grade silicon but polycrystalline silicon may be used for chamber parts. Additionally, the particle feed tube in which the particles are entrained in a gas flow and the vortex finder operating as the outlet at the center of the vortex may be formed of silicon. The milling and feed gas may be nitrogen supplied from a liquid-nitrogen tank lined with stainless steel. The feed pellets may be formed by chemical vapor deposition.

Abstract: The molding material or molding part for foundry purposes, comprising 1-10% of binding agent based on alkali silicate, an aggregate containing 1-10 percent by weight of amorphous silicon dioxide, remainder quartz sand with a grain size range of 0.01 to 5 mm, and to a process of producing a molding material and molding parts. The abstract of the disclosure is submitted herewith as required by 37 C.F.R. §1.72(b). As stated in 37 C.F.R. §1.72(b): A brief abstract of the technical disclosure in the specification must commence on a separate sheet, preferably following the claims, under the heading “Abstract of the Disclosure.” The purpose of the abstract is to enable the Patent and Trademark Office and the public generally to determine quickly from a cursory inspection the nature and gist of the technical disclosure. The abstract shall not be used for interpreting the scope of the claims.

Abstract: The production of low-loss, tunable composite ceramic materials with improved breakdown strengths is disclosed. The composite materials comprise ferroelectric perovskites such as barium strontium titanate or other ferroelectric perovskites combined with other phases such as low-loss silicate materials and/or other low-loss oxides. The composite materials are produced in sheet or tape form by methods such as tape casting. The composite tapes exhibit favorable tunability, low loss and tailorable dielectric properties, and can be used in various microwave devices.

Abstract: In a method of producing a cordierite honeycomb structure body, talc, kaolin, and alumina as prepared raw materials are mixed. The mixed raw materials are extruded and molded in an extrusion molding step. The obtained green body is cut into plural green bodies of a specified length. In a following drying step, the green body is dried and then fired in order to make the cordierite honeycomb structure body. In particular, the talc for use in the mixing step has IgLoss (Ignition Loss) within a range of 5.7 to 6.5 wt % which is obtained by firing at 1,000° C. for two hours.

Abstract: The present invention provides a sprayable composition comprising a ceramic particulate including albite, illite, and quart, and a metallic composition, including nickel, chromium, iron, and silicon. The sprayable composition may be a composite particle, a blend, or a cored wire. The present invention further provides an abradable coating formed on a metal substrate according to a method comprising the step of depositing the abradable coating on the metal substrate by thermal spraying of a sprayable composition comprising a ceramic particulate including albite, illite, and quartz, and a metallic composition, including nickel, chromium, iron and silicon. The sprayable composition may be a composite particle, a blend, or a cored wire. The abradable coating may be applied to a metal substrate such as steel, nickel-based alloys, and titanium.

Abstract: ESD safe ceramic component is provided which includes a sintered composition which is formed of a base material and a resistivity modifier. The base material includes a primary component and a secondary component, the primary component including Al2O3 and the secondary component including tetragonal-ZrO2.

Abstract: The present invention is focused on a revolutionary, low-cost (highly-scaleable) approach for the mass production of three-dimensional microcomponents: the biological reproduction of naturally-derived, biocatalytically-derived, and/or genetically-tailored three-dimensional microtemplates (e.g., frustules of diatoms, microskeletons of radiolarians, shells of mollusks) with desired dimensional features, followed by reactive conversion of such microtemplates into microcomponents with desired compositions that differ from the starting microtemplate and with dimensional features that are similar to those of the starting microtemplate. Because the shapes of such microcomponents may be tailored through genetic engineering of the shapes of the microtemplates, such microcomposites are considered to be Genetically-Engineered Materials (GEMs).

Abstract: A dielectric porcelain composition includes MgTiO3 and Mg2SiO4 and satisfies a+b=1 and 0<b<1, wherein a denotes a molar ratio of MgTiO3 and b denotes a molar ratio of Mg2SiO4. It can include MgTiO3 and CaTiO3 and satisfy a+c=1 and 0<c?0.15, wherein a has the same meaning as shown above and c denotes a molar ratio of CaTiO3. It can also include MgTiO3, Mg2SiO4 and CaTiO3 and satisfy a+b+c=1, 0<b<1 and 0<c?0.15, wherein a, b and c have the same meanings as shown above. These compositions can be manufactured, with the content of Mg2SiO4, the content of CatiO3 and the contents of Mg2SiO4 and CaTiO3 adjusted, respectively. These compositions can be used as dielectric materials to manufacture dielectric resonators.

Abstract: A sintered object of silicon monoxide for use as a material for forming silicon oxide thin films is provided of which the evaporation residue as determined by subjecting a sample thereof to thermogravimetry at a heating temperature of 1,300° C. and in a vacuum atmosphere, namely at a pressure of not higher than 10 Pa, is not more than 4% by mass relative to the sample before measurement. This sintered object can be produced by sintering SiO particles having a particle diameter of not smaller than 250 ?m, either after press forming thereof or during press forming thereof, in a non-oxygen atmosphere. This sintered object is high in evaporation rate and, when it is used as a material for film formation, an improvement in productivity in producing silicon oxide thin films can be expected. Thus, it can be widely applied in forming silicon oxide thin films useful as electric insulating films, mechanical protection films, optical films, barrier films of food packaging materials, etc.

Abstract: This invention provides a silicon composition comprising at least 15 wt % of hydrolysed silicon compounds and at least 3 wt % of a binder material. The silicon composition is used in the manufacture of ceramics. The hydrolysed silicon compounds can for example be the gel produced by hydrolysing higher boiling point organohalosilanes produced in the manufacture of organohalosilanes or halosilanes by the direct process.

Abstract: A bond coat composition is provided for applying to the surface of a ceramic composite component between the composite substrate and the thermal barrier coat. The composition includes an alumina powder, a silica-yielding liquid, glass frits, and sufficient solvent to permit mixing of the components and forming a bond coat.

Abstract: A block copolymer, preferably a block copolymer such as poly(isoprene-block-ethylene oxide), PI-b-PEO, is used as a structure directing agent for a polymer derived ceramic (PDC) precursor, preferably a silazane, most preferably a silazane commercially known as Ceraset. The PDC precursor is preferably polymerized after mixing with the block copolymer to form a nanostructured composite material. Through further heating steps, the nanostructured composite material can be transformed into a nanostructured non-oxide ceramic material, preferably a high temperature SiCN or SiC material.

Abstract: The present invention is directed to magnesium phosphate ceramics and their methods of manufacture. The composition of the invention is produced by combining a mixture of a substantially dry powder component with a liquid component. The substantially dry powder component comprises a sparsely soluble oxide powder, an alkali metal phosphate powder, a sparsely soluble silicate powder, with the balance of the substantially dry powder component comprising at least one powder selected from the group consisting of bioactive powders, biocompatible powders, fluorescent powders, fluoride releasing powders, and radiopaque powders. The liquid component comprises a pH modifying agent, a monovalent alkali metal phosphate in aqueous solution, the balance of the liquid component being water. The use of calcined magnesium oxide as the oxide powder and hydroxylapatite as the bioactive powder produces a self-setting ceramic that is particularly suited for use in dental and orthopedic applications.

Abstract: It is an object of the present invention to provide a hydrogen-doped silica powder that is useful in the formation of a quartz glass crucible that is capable of pulling a silicon single crystal without causing a state having dislocations in the silicon single crystal due to peeling of quartz glass segment. It is a further object of the invention to provide a quartz glass crucible for use in pulling a silicon single crystal whose inner surface is formed by use of the hydrogen-doped silica powder and a producing method of the silica powder.

Abstract: The present invention is focused on a revolutionary, low-cost (highly-scaleable) approach for the mass production of three-dimensional microcomponents: the biological reproduction of naturally-derived, biocatalytically-derived, and/or genetically-tailored three-dimensional microtemplates (e.g., frustules of diatoms, microskeletons of radiolarians, shells of mollusks) with desired dimensional features, followed by reactive conversion of such microtemplates into microcomponents with desired compositions that differ from the starting microtemplate and with dimensional features that are similar to those of the starting microtemplate. Because the shapes of such microcomponents may be tailored through genetic engineering of the shapes of the microtemplates, such microcomposites are considered to be Genetically-Engineered Materials (GEMs).

Abstract: Subjects for the invention are to obtain a quartz powder having a high purity and high quality and a process for producing the same and to obtain a glass molding formed by melting and molding the powder and extremely reduced in bubble inclusion. The invention provides a quartz powder, preferably a synthetic quartz powder obtained by the sol-gel method, which, upon heating from room temperature to 1,700° C., generates gases in which the amount of CO is 300 nl/g or smaller and the amount of CO2 is 30 nl/g or smaller.

Abstract: The present invention relates to an icosahedral, quasicrystalline compound or compound present in the form of an approximant having the nominal composition: TivCrwAlxSiyOz, in which v=60-65; w=25-30; x=0-6; Y=8-15; z=8-20; and in which the atom percent of oxygen is in the range of between 8 and 15%, and that of aluminum in the range of between 2 to 5%. Due to their layered structure and ceramic intermediate layers, compounds of this type exhibit excellent properties, in particular for use as coatings for gas turbine components, such as for example, rotor blades or guide vanes.

Abstract: A method of manufacturing a ceramic coating material which includes stirring a material including a complex oxide in the presence of a catalyst containing platinum group elements. The material is a sol-gel material which includes at least one of a hydrolysate and a polycondensate of the complex oxide.

Abstract: The invention provides porous silicon nitride ceramics that having uniform, fine closed pores and a manufacturing method thereof. Metal Si powder is mixed with a sintering additive, followed by thermal treatment, which is a pre-process for forming a specific grain boundary phase. Two-stage thermal treatment is thereafter performed by microwave heating at a temperature of 1000° C. or more. The metal Si powder is thereafter subjected to a nitriding reaction from its surface, the metal Si is thereafter diffused to nitride formed on the outer shell thereof such that porous silicon nitride ceramics having uniform, fine closed pores can be produced. Having a high ratio of closed pores and being superior in electrical/mechanical characteristics, the porous silicon nitride ceramics can display excellent characteristics if used, for example, for an electronic circuit board that requires an anti-hygroscopicity, a low dielectric constant, a low dielectric loss, and mechanical strength.

Abstract: A ceramic sintered body comprising from 90 to 99.8% by volume of cordierite and from 0.2 to 10% by volume of mullite based on 100% by weight of a total sum of the contents of the cordierite and the mullite, and having a density of 2.48 g/cm3 or more.

Abstract: A fired spinel complex oxide is produced by firing a mixture containing a slag by-produced in chromium refining, a reducer, and a silica-containing material, and is essentially composed of: 29 to 40 percent by weight of Fe2O3; 15 to 20 percent by weight of Al2O3; 9 to 14 percent by weight of MgO; 0 to 4 percent by weight of Na2O; 9 to 17 percent by weight of Cr2O3; 14 to 20 percent by weight of SiO2; and 2 percent by weight or less of CaO. The fired spinel complex oxide shows a Cu—K? X-ray diffraction pattern in which the ratio (b/a) of the diffraction peak intensity of the silica-containing material (b) in the vicinity of 2?=26.7° to the {113} plane diffraction peak intensity (a) in the vicinity of 2?=36° is 0.1 or less.