The objective of the present invention is to provide: a spherical magnesium oxide which has high sphericity and excellent moisture resistance, and has excellent fluidity by which a resin composition exhibits excellent fluidity when filled in a resin; and a method for producing the same. The present invention is a spherical magnesium oxide characterized in that: 10-2000 ppm of boron is contained; the total content of silicon and phosphorus is 300-4000 ppm; and the sphericity that can be read from the SEM photograph is 1.00-1.10, when the volume-based cumulative 50% particle diameter (D50) measured by means of a laser diffraction scattering particle size distribution measurement, is in the range of 3-200 m.

To provide magnesium oxide which is excellent in hydration resistance and hardly causes volume expansion due to hydration and the like, a resin composition containing the same, and a method for producing the magnesium oxide powder. Magnesium oxide powder having a coating layer mainly comprising basic magnesium carbonate in the surface layer, when the amounts of substances of water vapor and carbon dioxide among the gas generated by thermal decomposition at 50 to 500 C. are respectively designated as m-H.sub.2O and m-CO.sub.2, in a heating evolved gas analysis (EGA-MS) method, the molar fraction represented by m-CO.sub.2/(m-H.sub.2O+m-CO.sub.2) being within the range of 0.3 to 0.6.

To provide magnesium oxide which is excellent in hydration resistance and hardly causes volume expansion due to hydration and the like, a resin composition containing the same, and a method for producing the magnesium oxide powder. Magnesium oxide powder having a coating layer mainly comprising basic magnesium carbonate in the surface layer, when the amounts of substances of water vapor and carbon dioxide among the gas generated by thermal decomposition at 50 to 500 C. are respectively designated as m-H.sub.2O and m-CO.sub.2, in a heating evolved gas analysis (EGA-MS) method, the molar fraction represented by m-CO.sub.2/(m-H.sub.2O+m-CO.sub.2) being within the range of 0.3 to 0.6.

Provided are: a spherical magnesium oxide having not only high sphericity but also smooth surface and having excellent moisture resistance and excellent filling properties, and a method producing the same. In the present invention, by controlling the boron and iron contents of the calcined magnesium oxide to be in the respective predetermined ranges, there is provided a spherical magnesium oxide having a volume-based cumulative 50% particle diameter (D50), as measured by a laser diffraction/scattering particle size distribution measurement, in the range of from 3 to 200 m, which is the range for a relatively large particle diameter, and a high sphericity of 1.00 to 1.20, as measured from viewing a SEM photomicrograph, as well as smooth surface, and having excellent moisture resistance and excellent filling properties. A predetermined spherical magnesium oxide is provided by virtue of the synergies obtained from the boron content of 300 to 2,000 ppm and the iron content of 100 to 1,500 ppm.

Provided are: a spherical magnesium oxide having not only high sphericity but also smooth surface and having excellent moisture resistance and excellent filling properties, and a method producing the same. In the present invention, by controlling the boron and iron contents of the calcined magnesium oxide to be in the respective predetermined ranges, there is provided a spherical magnesium oxide having a volume-based cumulative 50% particle diameter (D50), as measured by a laser diffraction/scattering particle size distribution measurement, in the range of from 3 to 200 m, which is the range for a relatively large particle diameter, and a high sphericity of 1.00 to 1.20, as measured from viewing a SEM photomicrograph, as well as smooth surface, and having excellent moisture resistance and excellent filling properties. A predetermined spherical magnesium oxide is provided by virtue of the synergies obtained from the boron content of 300 to 2,000 ppm and the iron content of 100 to 1,500 ppm.

Provided is a magnesium oxide-containing spinel powder capable of producing a ceramic sintered body having high strength and excellent strength stability. In the magnesium oxide-containing spinel powder, a 50% particle diameter (D50) is 0.30 to 10.00 m, a ratio (D90-D50)/(D50-D10) of a difference between a 90% particle diameter (D90) and the 50% particle diameter (D50) and a difference between the 50% particle diameter (D50) and a 10% particle diameter (D10) is 1.0 to 5.0, and a composition ratio of Mg and Al in terms of an oxide equivalent content is 50 to 90% by weight of MgO and 10 to 50% by weight of Al.sub.2O.sub.3.

A process and apparatus for manufacture of biocide products are described. The biocide properties arise from the caustic calcined powder, from carbonates such as such as magnesite and dolomite, and from hydroxides such as brucite. The method of manufacture is based on the production of high surface area oxide particles using an indirectly heated counterflow reactors for specifically calcining the carbonates and the hydroxides without significant sintering. The biocide products may be a powder or a hydrated slurry. A hydrated slurry is preferred for agricultural applications as a spray. For aquaculture applications, the products have a preferred particle size distribution to impact the aquatic and benthic ecosystems, and a Ca/Mg ratio that promotes the growth of the cultivates species when applied as a powder or a slurry. For applications such as a marine paint, the powder product or the slurry product is mixed with various agents to form a setting coating, and is applied to the infrastructure that is otherwise subject to biofilm growth.

Nanoplatelet forms of metal hydroxide and metal oxide are provided, as well as methods for preparing same. The nanoplatelets are suitable for use as fire retardants and as agents for chemical or biological decontamination.

Nanoplatelet forms of metal hydroxide and metal oxide are provided, as well as methods for preparing same. The nanoplatelets are suitable for use as fire retardants and as agents for chemical or biological decontamination.

A coated member manufacturing method includes: an application step for applying a magnesium hydroxide solution on a surface of a FeCo-based alloy base material; and a baking step for baking the base material after the application step at 600-900? C. to form a magnesium oxide coating on the base material. This coated member has, on a FeCo-based alloy base material, a baked coating of magnesium oxide having a lattice constant of 4.20-4.23 ?.