A method for simultaneously preparing an iron oxide red pigment and an aromatic amine is provided. In the method, an aromatic nitro compound and ferrous iron are first used to prepare an iron oxide red seed crystal under the action of a catalyst, and then iron powder is used to reduce the aromatic nitro compound and generate iron oxide in situ which grows into iron oxide red with pigment performance on the seed crystal. The method provides a clean and economical way for the reduction of an aromatic nitro compound (especially those in which there are other easily-reduced substituents on an aromatic ring) to prepare an aromatic amine.

A method for simultaneously preparing an iron oxide red pigment and an aromatic amine is provided. In the method, an aromatic nitro compound and ferrous iron are first used to prepare an iron oxide red seed crystal under the action of a catalyst, and then iron powder is used to reduce the aromatic nitro compound and generate iron oxide in situ which grows into iron oxide red with pigment performance on the seed crystal. The method provides a clean and economical way for the reduction of an aromatic nitro compound (especially those in which there are other easily-reduced substituents on an aromatic ring) to prepare an aromatic amine.

Provided is a method for producing hematite for ironmaking, capable of using a conventional Ca-based neutralizing agent and a base rock-derived neutralizing agent other than the Ca-based neutralizing agent. The method is performed by a process of adding a mineral acid and an oxidizing agent to an ore containing iron and a valuable metal and then leaching the valuable metal under high temperature and pressure, and includes (1) a high-pressure acid leaching step, (2) a preliminary neutralization step, (3) a first solid-liquid separation step, (4) a neutralization step, (5) a second neutralization step, (6) a third solid-liquid separation step, (7) a step of adding part of the Fe-enriched slurry as a seed crystal in the neutralization step (4), and (8) a second solid-liquid separation step.

Provided is a method for producing hematite for ironmaking, capable of using a conventional Ca-based neutralizing agent and a base rock-derived neutralizing agent other than the Ca-based neutralizing agent. The method is performed by a process of adding a mineral acid and an oxidizing agent to an ore containing iron and a valuable metal and then leaching the valuable metal under high temperature and pressure, and includes (1) a high-pressure acid leaching step, (2) a preliminary neutralization step, (3) a first solid-liquid separation step, (4) a neutralization step, (5) a second neutralization step, (6) a third solid-liquid separation step, (7) a step of adding part of the Fe-enriched slurry as a seed crystal in the neutralization step (4), and (8) a second solid-liquid separation step.

A self-assembling structure using non-equilibrium driving forces leading to “living crystals” and other maniputable particles with a complex dynamics. The dynamic self-assembly assembly results from a competition between self-propulsion of particles and an attractive interaction between the particles. As a result of non-equilibrium driving forces, the crystals form, grow, collide, anneal, repair themselves and spontaneously self-destruct, thereby enabling reconfiguration and assembly to achieve a desired property.

A self-assembling structure using non-equilibrium driving forces leading to “living crystals” and other maniputable particles with a complex dynamics. The dynamic self-assembly assembly results from a competition between self-propulsion of particles and an attractive interaction between the particles. As a result of non-equilibrium driving forces, the crystals form, grow, collide, anneal, repair themselves and spontaneously self-destruct, thereby enabling reconfiguration and assembly to achieve a desired property.

The present invention relates to a method of reducing a metal oxide comprising the steps of preparing a mixture by mixing a metal oxide and a metal hydride (step 1) and reducing the mixture by heat treatment (step 2) and a method of producing a photocatalyst using the same, and The method of reducing a metal oxide of the present invention can easily reduce such metal oxides as TiO.sub.2, ZrO.sub.2, V.sub.2O.sub.3, and Fe.sub.2O.sub.3.

The present invention relates to a method of reducing a metal oxide comprising the steps of preparing a mixture by mixing a metal oxide and a metal hydride (step 1) and reducing the mixture by heat treatment (step 2) and a method of producing a photocatalyst using the same, and The method of reducing a metal oxide of the present invention can easily reduce such metal oxides as TiO.sub.2, ZrO.sub.2, V.sub.2O.sub.3, and Fe.sub.2O.sub.3.

An object of the present invention is to provide a magnetic powder having a narrow particle size distribution of epsilon-type iron oxide particles, and another object is to provide magnetic powder suitable for magnetic recording medium by improving particle size distribution, and provide epsilon-type iron oxide magnetic particles and related technologies in which a number average particle diameter of major diameters (D.sub.50) is 10 to 20 nm, a 90% cumulative particle diameter (D.sub.90) is 30 nm or less, and a geometric standard deviation (σ.sub.g) of major diameters is 1.45 or less, which are obtained by TEM observation.

An object of the present invention is to provide a magnetic powder having a narrow particle size distribution of epsilon-type iron oxide particles, and another object is to provide magnetic powder suitable for magnetic recording medium by improving particle size distribution, and provide epsilon-type iron oxide magnetic particles and related technologies in which a number average particle diameter of major diameters (D.sub.50) is 10 to 20 nm, a 90% cumulative particle diameter (D.sub.90) is 30 nm or less, and a geometric standard deviation (σ.sub.g) of major diameters is 1.45 or less, which are obtained by TEM observation.