Iron oxide is an inorganic substance with the chemical formula Fe2O3, which is a red or dark red amorphous powder. The relative density is 5~5.25, and the melting point is 1565°C (decomposition at the same time). Insoluble in water, soluble in hydrochloric acid and sulfuric acid, slightly soluble in nitric acid. The hiding power and tinting power are very strong, and there is no oil permeability and water permeability. Stable in the atmosphere and sunlight, resistant to foul gas, high temperature and alkali. The dry-process products of this product have coarse and hard crystal particles, and are suitable for magnetic materials, polishing and abrasive materials. Wet-processed products have fine and soft crystalline particles and are suitable for coating and ink industries.

Magnetic materials

Because of its special superparamagnetic properties, magnetic iron oxide particles are widely used in giant magnetoresistance, magnetic liquid and magnetic recording, soft magnetism, permanent magnet, magnetic refrigeration, giant magnetoresistance materials, magneto-optical devices, magnetic detectors, etc. with broadly application foreground. Video tapes generally use acicular iron or iron oxide magnetic ultrafine particles, while nano-iron oxide is a new type of magnetic recording material. Soft ferrite has been widely used in radio communications, radio and television, automatic control, space navigation, radar navigation, measuring instruments, computers, printing, household appliances and biomedicine.

Pigment field

As a pigment, iron oxide is widely used in high-grade automotive coatings, architectural coatings, anti-corrosion coatings, and powder coatings. It is a good environmental protection coating. The annual consumption of iron oxide pigments in the world exceeds 1 million tons, second only to titanium dioxide. It ranks second in inorganic pigments. Using iron oxide as a pigment not only maintains the good heat resistance, weather resistance and ultraviolet absorption of general inorganic pigments, but also can be well dispersed in the oily carrier, and the paint or ink prepared with it has satisfactory transparency. . Using iron oxide with semiconductor properties to make coatings, due to its high conductivity, it can play a role in electrostatic shielding.

Iron oxide is a commonly used colorant in glass production. Iron oxide colored glass can absorb both ultraviolet and infrared rays, so it is widely used in the manufacture of heat-absorbing glass, sunglasses glass, industrial protective glasses glass and military anti-infrared coatings. At the same time, it has the functions of low price, absorbing heat rays and ultraviolet rays.

In addition, iron oxide pigments are also widely used abroad as colorants and protective agents for wood coating. The use of transparent iron oxide pigments instead of traditional pigments preserves the clear wood grain of the wood, while the inherently high lightfastness makes the furniture color durable. Ultraviolet rays in sunlight can decompose lignin of wood and destroy the cell structure, resulting in wood aging, while nano-iron oxide pigments can protect wood because of their small particles and uniform distribution, which do not scatter light and absorb ultraviolet radiation. .

The field of catalysis

α-Fe2O3 powder particles have a huge specific surface, and the surface effect is obvious, which is a good catalyst. Due to the small size of iron oxide particles and the large volume percentage of the surface, the bond state and electronic state of the surface are different from those of the particle, and the coordination of surface atoms is different, which leads to the increase of active sites on the surface. The activity and selectivity of the catalyst made of nano-α-Fe2O3 particles are higher than those of ordinary catalysts, and the service life is long and easy to operate. Nano-α-Fe2O3 has been directly used as a catalyst for the oxidation, reduction and synthesis of high molecular polymers. When it is used in petroleum refining, it can increase the cracking speed by 1 to 5 times. As a catalyst for solid combustion agents, the combustion speed can be higher than The burning rate of common incendiary agents is increased by 1 to 10 times, which is very beneficial to the manufacture of high-performance rockets and missiles.

Biomedical and other fields

Nano-FeO plays an important role in medicinal capsules, drug synthesis, biomedical technology and other fields. In addition to being used in magnetic materials, pigments, catalysis, and biomedicine, α-Fe2O3 also has broad application prospects in other fields. For example, nano-scale iron oxide has good adsorption effect on Cr(VI), high adsorption efficiency, short adsorption time, and can be recycled and reused. It has certain application value for treating Cr(VI) in environmental sewage; The gas-sensing material made of nano-α-Fe2O3 has the characteristics of fast response speed, strong selectivity, high sensitivity and good stability; when preparing transparent iron oxide, if the content of arsenic and heavy metals is strictly controlled, it can be used in food , cosmetics and other industries; because transparent iron oxide has the characteristics of transparent coloring, acid and alkali resistance and non-toxicity, it can also be used as a coating for the inner wall of can lids, and has a large number of applications in the United States.