An insulating filler composed of a mixed powder in which a hydrophobic fumed oxide powder having an average primary particle size D.sub.1, which is smaller than an average primary particle size D.sub.2, is adhered to the surface of a magnesium oxide powder and/or a nitride-based inorganic powder having the average primary particle size D.sub.2, wherein: the ratio D.sub.1/D.sub.2 of the average primary particle size D.sub.1 to the average primary particle size D.sub.2 is 6×10.sup.−5 to 3×10.sup.−3; the volume resistivity of the mixed powder is 1×10.sup.11 Ω.Math.m or more; and the content ratio of the hydrophobic fumed oxide powder in the mixed powder is 5-30 mass %. Also provided is an insulating material in which the above-mentioned insulating filler is contained in a resin molded body.

An ingot mold for curing fused and melted material is provided. The ingot mold includes a steel box, a foamed carbon layer, and a graphite block layer. The foamed carbon layer is formed inside the steel box. The graphite block layer is formed inside the steel box.

An ingot mold for curing fused and melted material is provided. The ingot mold includes a steel box, a foamed carbon layer, and a graphite block layer. The foamed carbon layer is formed inside the steel box. The graphite block layer is formed inside the steel box.

A calcium and/or magnesium additive for membrane fouling control made up of particles for forming a dynamic protective layer on the membrane for fouling control of the membrane, when added in the liquid flowing through the membrane, wherein the particles are synthetic mineral precipitate particles based on calcium and/or magnesium selected from the group consisting of ultrafine synthetic mineral precipitate particles and microfine synthetic mineral precipitate particles, as well as a process and system for membrane fouling control.

A calcium and/or magnesium additive for membrane fouling control made up of particles for forming a dynamic protective layer on the membrane for fouling control of the membrane, when added in the liquid flowing through the membrane, wherein the particles are synthetic mineral precipitate particles based on calcium and/or magnesium selected from the group consisting of ultrafine synthetic mineral precipitate particles and microfine synthetic mineral precipitate particles, as well as a process and system for membrane fouling control.

This magnesium oxide powder contains secondary particles in which a plurality of primary particles of magnesium oxide having a crystal phase and a grain boundary phase are at least partially fused together by the grain boundary phase, and a median diameter obtained by a laser diffraction scattering method is 300 .Math.m or less.

This magnesium oxide powder contains secondary particles in which a plurality of primary particles of magnesium oxide having a crystal phase and a grain boundary phase are at least partially fused together by the grain boundary phase, and a median diameter obtained by a laser diffraction scattering method is 300 .Math.m or less.

Provided are magnesium oxide particles which are good in dispersibility in a resin or rubber, can function sufficiently as an acid acceptor or scorch retarder, and do not lower, even after combined with a resin or rubber, material properties thereof; a resin composition; a rubber composition; and a shaped body. The magnesium oxide particles satisfying the following (A) to (C): (A) an average particle size is 5 μm or less; (B) a BET specific surface area is 20 m.sup.2/g or more and 200 m.sup.2/g or less; and (C) a screen residue by a sieve opening of 45 μm is 0.1% by weight or less.

Provided are magnesium oxide particles which are good in dispersibility in a resin or rubber, can function sufficiently as an acid acceptor or scorch retarder, and do not lower, even after combined with a resin or rubber, material properties thereof; a resin composition; a rubber composition; and a shaped body. The magnesium oxide particles satisfying the following (A) to (C): (A) an average particle size is 5 μm or less; (B) a BET specific surface area is 20 m.sup.2/g or more and 200 m.sup.2/g or less; and (C) a screen residue by a sieve opening of 45 μm is 0.1% by weight or less.

Provided is a method for manufacturing a mesoporous inorganic oxide, which includes preparing a mixture of a metal salt selected from the group consisting of at least one kind of alkali metal-containing compound, at least one kind of alkaline earth metal-containing compound, and any combination thereof and an amorphous inorganic oxide; sintering the mixture of a metal salt and an amorphous inorganic oxide; and removing the metal salt contained in the sintered mixture, and a mesoporous inorganic oxide that is manufactured by the above method and is composed of an aggregate of inorganic oxide particles having a size of from 2 nm to 5 nm.

According to the present invention, it is possible to provide a method for manufacturing a mesoporous inorganic oxide which has a simplified manufacturing process, has a short period of manufacturing time of about 1 day, does not generate secondary environmental contaminants to be environmentally friendly, and enables mass production, and a mesoporous inorganic oxide which has a dramatically decreased particle size and thus has an increased specific surface area and increased active sites.