A material synthesis method may comprise: adding at least one liquid precursor solution to an atomizer device; generating by the atomizer device an aerosol comprising liquid droplets; transporting the aerosol to a reactive zone for evaporating one or more solvents from the aerosol; and collecting particles synthesized from at least evaporating the aerosol.

A process for producing a magnesium aluminate spinel comprising the steps of: i) preparing a magnesium suspension containing a magnesium compound; ii) preparing an aluminum suspension containing an aluminum compound; iii) feeding the magnesium suspension and aluminum suspension independently into a spray dryer nozzle to form a mixed magnesium, aluminum suspension; iv) feeding the mixed magnesium, aluminium suspension from the spray dryer nozzle into a spray dryer to form a mixed magnesium and aluminum compound; and v) calcining the mixed magnesium and aluminum compound to generate a magnesium aluminate spinel.

Provided is a zirconia sintered body that uses coloring of cerium oxide, the zirconia sintered body exhibiting a bright red color. The zirconia sintered body includes an oxide of cerium is an amount of 0.5% by mole or more and less than 4% by mole in terms of CeO.sub.2, yttria in an amount of 2% by mole or more and less than 6% by mole, an oxide of aluminum in an amount of 0.1% by weight or more and less than 2% by weight, and the balance being zirconia. The oxide of cerium contains trivalent cerium, and the zirconia has a crystal structure including a tetragonal phase.

Provided are a liquid-crystal-display protection plate that has a high strength, is produced at a reduced cost, and has a shape including a curved surface; and a method for producing the liquid-crystal-display protection plate. The liquid-crystal-display protection plate is formed of a spinel sintered body. The spinel sintered body has an average grain size of 10 m or more and 100 m or less. The liquid-crystal-display protection plate has a shape including a curved surface.

The present invention relates to a method for obtaining calcium aluminates for metallurgical use from non-saline aluminum slags by means of reactive grinding and thermal treatment.

Particles for a monolithic refractory are made of a spinet porous sintered body which is represented by a chemical formula of MgAl.sub.2O.sub.4, wherein pores having a pore size of 0.01 m or more and less than 0.8 m occupy 10 vol % or more and 50 vol % or less with respect to a total volume of pores having a pore size of 10 m or less in the particles, and the particles for a monolithic refractory have grain size distribution in which particles having a particle size of less than 45 m occupy 60 vol % or less, particles having a particle size of 45 m or more and less than 100 m occupy 20 vol % or more and 60 vol % or less, and particles having a particle size of 100 m or more and 1000 m or less occupy 10 vol % or more and 50 vol % or less.

The invention related to a material that can stably hold an imide anion (NH.sup.2) therein even in the atmosphere or in a solvent, and a method for synthesizing the material and a use of the material. A mayenite-type compound into which imide anions are incorporated at a concentration of 110.sup.18 cm.sup.3 or more are provided. The mayenite-type compound can be produced by heating a mayenite-type compound including electrons or free oxygen ions in a cage thereof, in liquefied ammonia at 450 to 700 C. and at a pressure of 30 to 100 MPa. The compound has properties such that active imide anions can be easily incorporated into the compound and the active imide anions can be easily released in the form of ammonia from the compound, and the compound has chemical stability.

Disclosed is a method for manufacturing calcium aluminates in an industrial furnace, according to which, continuously, into a tank made of refractory material containing a molten pool that is constantly heated, fine particles are introduced of a raw material source of alumina and/or of aluminium and of a raw material source of calcium oxide and/or of calcium having a median diameter d50 less than or equal to 6,000 m in order to melt the fine particles of raw material, and, continuously, at the outlet of the tank a mass of liquid calcium aluminates is recovered.

An object of the present invention is to provide a method for producing conductive mayenite, with which a reaction is completed in a short time, an operation can be simplified, the reaction is easily controlled, and the cost of energy can be reduced. The present invention is a method for producing conductive mayenite, characterized by mixing a mayenite type compound with a carbon component, placing the resulting mixture in an airtight container, and irradiating the mixture with a microwave in an inert gas atmosphere or in a vacuum atmosphere to heat the mixture.

A process for preparing particles of a layered double hydroxide of the general formula

[M.sub.p.sup.z+M.sub.q.sup.y+(OH).sub.2].sup.a+(X.sup.n).sub.a/n.bH.sub.2O(I)

wherein M.sup.z+ and M.sup.y+ are metal cations or mixtures of metal cations, z=1 or 2; y=3 or 4; p+q=1; b=0 to 10, X.sup.n is an anion, n is 1 to 5 and a is determined by p, q, y and z such that a=zp+yq2, comprises (a) mixing, in aqueous solution, M.sup.z+ cations, M.sup.y+ cations and X.sup.n anions, with a base; and (b) allowing the layered double hydroxide of formula (I) to precipitate from the solution mixed in step (a).

Preferably, M is Li, Mg, Zn, Fe, Ni, Co, Cu, Ca, or a mixture of two or more. Preferably, y is 3, and M is Al, Ga, In, Fe or a mixture of two or more thereof. Also provided are particles obtainable by the process, especially wherein M is Ca, M is Al, and X.sup.n is NO.sub.3.sup.. Particles of a layered double hydroxide wherein the particles have a particle size of not greater than 2000 nm, preferably not greater than 300 nm and especially not greater than 100 nm, are also provided. The layered double hydroxides according to the invention are useful in certain applications, for example, as adsorbents, coatings and catalyst supports.