A process and apparatus for manufacture of oxide products for use as biocide, chemical detoxifying, and catalytic support products, from caustic calcined carbonate powder, preferably from magnesite, dolomite, or hydromagnesite, is described. These oxide particles are characterized by high surface area, high porosity and a high degree of calcination, and the method of manufacture utilizes an indirectly heated counterflow reactor. The oxides may be used as a powder, granules, or formulated into a slurry and used as a spray, emulsion, foam or fog, or the powder product may be directly applied. Also described is the formation of particles with microstructures defined by at least one nano-crystalline structure positioned on the outer surface of the particles.

A method of producing a metal carbonate from an ultramafic rock material is provided. The method includes providing an ultramafic rock material comprising a metal silicate; reacting the ultramafic rock material with an acid to form a mixture comprising a salt of the metal; contacting the mixture comprising a salt of the metal with oxygen so as to aerate impurities in the mixture and/or to remove residual acid from the mixture; heating the resultant mixture to decompose the salt of the metal to form metal oxide; and reacting the metal oxide with aqueous ammonium carbonate to obtain the metal carbonate. A system for producing a metal carbonate from ultramafic rock material is also provided.

A method of producing a metal carbonate from an ultramafic rock material is provided. The method includes providing an ultramafic rock material comprising a metal silicate; reacting the ultramafic rock material with an acid to form a mixture comprising a salt of the metal; contacting the mixture comprising a salt of the metal with oxygen so as to aerate impurities in the mixture and/or to remove residual acid from the mixture; heating the resultant mixture to decompose the salt of the metal to form metal oxide; and reacting the metal oxide with aqueous ammonium carbonate to obtain the metal carbonate. A system for producing a metal carbonate from ultramafic rock material is also provided.

Composite particles are disclosed comprising magnesium oxide, iron oxide, and biochar; and methods of making and using the composite particles. The composite particles may be used to recover solutes including phosphate, nitrate, ammonium, and organic compounds from aqueous solution, and the resulting solute-loaded particles may be used as a fertilizer to enhance plant growth. The composites be used to remove pollutants from agricultural runoff, wastewater, and surface water. The particles possess magnetic properties that enhance their recovery following solute adsorption.

The object of the present invention is to provide spherical magnesium oxide having high sphericity and excellent moisture resistance and filling properties in resin without including a certain amount of boron or lithium, and a method for producing the same. The present invention is spherical magnesium oxide having the total content of elements belonging to the 3rd to 4th periods of the periodic table (except for the elements belonging to the 2nd and 18th groups) and yttrium of 500 to 12,000 ppm, having a volume-based cumulative 50% particle diameter (D50) measured by a laser diffraction/scattering particle size distribution measurement of 1 to 200 m, and wherein a sphericity read from a SEM photomicrograph of 1.00 to 1.20.

The object of the present invention is to provide spherical magnesium oxide having high sphericity and excellent moisture resistance and filling properties in resin without including a certain amount of boron or lithium, and a method for producing the same. The present invention is spherical magnesium oxide having the total content of elements belonging to the 3rd to 4th periods of the periodic table (except for the elements belonging to the 2nd and 18th groups) and yttrium of 500 to 12,000 ppm, having a volume-based cumulative 50% particle diameter (D50) measured by a laser diffraction/scattering particle size distribution measurement of 1 to 200 m, and wherein a sphericity read from a SEM photomicrograph of 1.00 to 1.20.

An object of the present invention is to provide magnesium oxide particles that have a high heat conductivity and excellent properties as heat-dissipating filler, and can prevent problems such as soft errors in the memory. The magnesium oxide particles have a BET specific surface area of 0.1 to 17 m.sup.2/g, and an dose of 0.005 c/cm.sup.2.Math.Hr or lower, the particles exhibiting a relation between an X-ray diffraction peak intensity y (cps) at a Bragg angle (2) of 42.80 to 43.00 and the BET specific surface area x (m.sup.2/g) as represented by the following inequality (1):
y960x+33000(1).

An object of the present invention is to provide magnesium oxide particles that have a high heat conductivity and excellent properties as heat-dissipating filler, and can prevent problems such as soft errors in the memory. The magnesium oxide particles have a BET specific surface area of 0.1 to 17 m.sup.2/g, and an dose of 0.005 c/cm.sup.2.Math.Hr or lower, the particles exhibiting a relation between an X-ray diffraction peak intensity y (cps) at a Bragg angle (2) of 42.80 to 43.00 and the BET specific surface area x (m.sup.2/g) as represented by the following inequality (1):
y960x+33000(1).

A p-type oxide which is amorphous and is represented by the following compositional formula: xAO.yCu.sub.2O where x denotes a proportion by mole of AO and y denotes a proportion by mole of Cu.sub.2O and x and y satisfy the following expressions: 0x<100 and x+y=100, and A is any one of Mg, Ca, Sr and Ba, or a mixture containing at least one selected from the group consisting of Mg, Ca, Sr and Ba.

A p-type oxide which is amorphous and is represented by the following compositional formula: xAO.yCu.sub.2O where x denotes a proportion by mole of AO and y denotes a proportion by mole of Cu.sub.2O and x and y satisfy the following expressions: 0x<100 and x+y=100, and A is any one of Mg, Ca, Sr and Ba, or a mixture containing at least one selected from the group consisting of Mg, Ca, Sr and Ba.