Iron oxide, also known as hematite, burnt hematite, burnt ochre, iron red, red powder, Venetian red (mainly composed of iron oxide), etc. The chemical formula is FeO(OH).2O3It is soluble in strong and medium acids and appears as a red brown powder. This red brown powder is a low-grade pigment, known in industry as iron oxide red, which is used in paints, inks, and rubber industries. It can also serve as a catalyst, a polishing agent for glass, gems, and metals, and can be used as an iron-making raw material.
On October 27, 2017, the International Agency for Research on Cancer (IARC), part of the World Health Organization, released a preliminary reference list of carcinogens. Iron oxide is listed in Group 3 of the carcinogen list.1
中文名氧化铁英文名Ferric oxide别称"铁红"Iron(III) oxide化学式Fe2O3，分子量159.6882，CAS号是13463-67-7。Melting point: 1565°C. Boiling point: 3414°C. Insoluble in water. Density: 5.24 g/cm3. Appearance: Red brown powder.
Chinese alias: C.I. Pigment Red 101; Transparent Iron Wire; Transparent Iron Oxide Red; High Magnetic Permeability Iron Oxide; Iron(III) Oxide (Medicine); Iron Oxide for Ferrites; Iron Oxide Hydroxide; Iron Oxide, Brown-Red; α-Phase Iron Oxide; Iron Red Powder; Iron Oxide Red
英文名称：Iron(Ⅲ) oxide
English alias: CI 77491 CI Pigment Red 101 CI Pigment Red 101 and 102 CI Pigment Red 102 Ferric oxide Iron Ⅲ Oxide Anhydrous diiron trioxide E 172 Iron Ⅲ oxide calcined Ironoxide anhydrous Ironoxideredbrownpowder Iron oxide precipitated Ferric oxidemedicinal Ferric oxide for ferrite Iron Ⅲ oxide red HematiteIRON OXIDE RED CIP R101 Iron III oxide diferric oxygen2 anion oxooxoferriooxyiron Iron Oxide
Physical properties
CAS号：1309-37-1; 1317-60-8; 1332-37-2
EINECS号：215-168-2; 215-275-4; 215-570-8
Molecular weight: 159.6882
Iron oxide is the main component of rust. The main cause of rust is that when iron metal reacts with water and oxygen in the presence of impurities such as carbon, iron metal will rust. It is used in industries such as painting, ink, rubber, as a catalyst, polishing agent for glass, gems, and metals, and can be used as a raw material for iron smelting. The most important application of iron oxide is as a pigment. It is divided into iron oxide red, iron oxide yellow, iron oxide black, and iron oxide brown, which is made by mixing iron oxide red, iron oxide black (and iron oxide yellow); iron oxide orange is made by mixing iron oxide red and iron oxide yellow; iron oxide green is made by mixing blue phthalocyanine blue and iron oxide yellow.
Stability: Stable, dissolves in hydrochloric acid and dilute sulfuric acid to form iron salts. Iron in a displacement reaction generates iron ions.
Fe2O3+6HCl=2FeCl3+3H2O Fe2O3+3H2SO4=Fe2SO4")3+3H2O
Storage and Transportation Conditions: Store in a dry place, avoid moisture, avoid high temperatures, and isolate from acids and bases. According to the above storage conditions, the effective storage period of unopened packaging products is three years.
Solubility: Insoluble in water, does not react with water. Soluble in acid, reacts with acid. Does not react with NaOH.
Oxidizing: Under high temperature, it is oxidized by CO and H2Al, C, Si and other elements can be reduced.
Fe2O3: "2Al + 3O2 =点燃= 2Fe + 3O22O3
Fe2O3+3CO = 高温 = 2Fe + 3CO2
2Fe2O3+3C = 高温 = 4Fe + 3CO2up
2Fe2O3+3Si = 高温 = 4Fe + 3SiO2
Chemical properties
Fe2O3 reacts with acid to form iron salts and water.
Example: Fe2O3+6HCl=2FeCl3+3H2O
Aluminum Thermal Reaction
When aluminum is mixed with iron oxide, it forms an aluminum-thermite mixture. When heated, it produces aluminum oxide and iron.
Chemical formula: 2Al + Fe2O3"=△=Al2O3+2Fe
⑶ Carbon and carbon monoxide reduction
Iron oxide can be heated with carbon, and iron and carbon dioxide are extracted.
Chemical formula: 3C + 2Fe2O3"= High temperature = 4Fe + 3CO2up
Iron oxide can be heated with carbon monoxide to generate iron and carbon dioxide.
Chemical formula: 3CO + Fe2O3=高温=2Fe+3CO2
Physical properties
Appearance: Red brown powder
Density: 5.24 g/cm3
Melting point: 1565°C (decomposition)
From Wikipedia
Existence form: Minerals: Hematite, Ochre
Alpha-type crystal structure:
Magnetic: In its natural state, iron oxide has an α-type crystal structure and is not magnetic. However, if iron(III) oxide is subjected to special treatment, it can form a γ-type crystal structure, which is magnetic but not stable and tends to revert to the α-type.
Preparation Method
Preparation methods include wet and dry processes. Wet process products have small crystalline structures, soft grains, and are easier to grind, making them suitable for use as pigments. Dry process products, on the other hand, have larger crystals and harder grains, making them suitable for use as magnetic materials and polishing and grinding materials.
"湿法"可以翻译为 "wet method".
FeSO4+2NaOH=Fe(OH)2plus sodium2SO4
4Fe(OH)2+O2+2H2O=4Fe(OH)3
4FeSO4+4H2O+O2=2Fe2O3↓+4H2SO4
Iron + Hydrogen2SO4=FeSO4+H2up
A certain amount of 5% ferrous sulfate solution is rapidly reacted with an excess of sodium hydroxide solution (requiring an excess of 0.04～0.08g/ml) at room temperature, allowing it to completely turn into a red-brown ferric hydroxide colloid solution, serving as the crystalline nucleus for the deposition of iron oxide. Using the above-mentioned nucleus as the carrier, with ferrous sulfate as the medium, air is introduced, at 75～85℃ under the presence of metal iron, ferrous sulfate reacts with oxygen in the air to generate iron oxide (i.e., iron red) and deposit it on the nucleus. Meanwhile, the sulfate in the solution reacts with metal iron to regenerate ferrous sulfate, which is then oxidized by air to iron red and continues to deposit. This cycle continues until the entire process is completed, resulting in the generation of red iron oxide.
By burning iron(II) compounds or iron(III) hydroxides in air, one can obtain iron oxide.
4Fe3O4+O2=high=Wen=6Fe2O3
In humid air, a thin layer of water adsorbs on the surface of steel, and this layer contains a small amount of hydrogen.plusAnd OH-It also dissolves oxygen, resulting in the formation of an electrolyte solution on the surface of steel. This solution reacts with the iron and the small amount of carbon in the steel (due to impurities) to form countless microscopic primary cells. In these primary cells, iron serves as the negative electrode, while carbon serves as the positive electrode. Iron loses electrons and is oxidized:
Anode: 2FeUnderline4e-=2Fe2+
Anode: 2H2O+O2+4e-=4OH-
Electrical corrosion is the main cause of steel corrosion.
Continue the reaction after this:
Fe2+2 hydroxide-Fe(OH)2
4Fe(OH)2+O2+2H2O=4Fe(OH)3
Fe(OH)23+nH2O=Fe2O3·nH2O+3H2O
In junior high school chemistry, hydrochloric acid (HCl) can be used to remove iron rust.
The equation is: Fe2O3+6HCl=2FeCl3+3H2O
dry method
When nitric acid reacts with iron filings to form iron(II) nitrate, it is cooled and crystallized, then dehydrated and dried. After grinding, it is calcined at 600-700°C for 8-10 hours, followed by washing, drying, and grinding to produce iron oxide red. Alternatively, iron oxide yellow can be used as the raw material, calcined at 600-700°C to produce iron oxide red.3")3→2Fe2O3+12 NO2↑+3O2↑ Fe2O3·nH2O→Fe2O3+nH2O; First, transparent iron oxide yellow is prepared (the method is referred to in the preparation of transparent iron oxide yellow), and then it is calcined and dehydrated to obtain transparent iron oxide red. The 2α-FeOOH==△==2α-FeSO3+H2O
Adopt the neutral precipitation method. First, prepare iron oxide black, and then heat-treat it at high temperature to obtain transparent iron oxide wires. Add 0.5 mol/L concentration of FeCl3·6H2Heat the O solution until it boils and hydrolyzes until red brown colloidal particles appear (solution 1). Take an equal volume of 0.25 mol/L FeCl2Solution (prepared by reacting metal iron with hydrochloric acid), adjust to the white precipitate no longer disappears with dilute ammonia (solution 2). Combine solution 1 and solution 2, stir, and add an appropriate amount of hydroxycarboxylic acid complexing agent and buffer, maintain constant temperature at 80°C. As the reaction proceeds, black Fe3O4Generate. The reaction is over, and the Fe will be produced.3O4Crystallization transfer to pH 8, containing Fe3O4Surface treatment is performed in a solution of sodium oleate with a mass ratio of 10%～20%, and the suspension is stirred. The temperature is maintained at 80℃ for 0.5 hours. Afterwards, the suspension is adjusted to pH = 6～6.5 with dilute hydrochloric acid (1:3), and the Fe3O4Oleic acid adsorption coating (black flocculent) is filtered, and then it is stirred and washed with hot water several times. The product is then dried at a vacuum of 50-60°C to obtain a loose powdery Fe.3O4O3O4Slowly heat to 550～600℃ and calcine for 0.5h to obtain a uniformly dispersed transparent iron oxide red, α-Fe.2O3Microscopic particles.
Made from natural pyrite. Obtained by weathering iron(II) sulfate or iron(III) oxide, then calcined. Obtained by dehydration of iron(III) hydroxide. By-product in the manufacture of sulfuric acid, aniline, aluminum oxide, etc. Obtained by heating iron(II) carbonate or iron(III) nitrate at high temperature. Obtained by heating iron(II) sulfate to over 650°C.
Mica-Hematite Method: After the mica-hematite ore is selected, it is ground into a concentrate powder in a wet ball mill, dehydrated, dried, cooled, and then crushed to 325 mesh, screened, and made into mica-based iron oxide.
Ferrous Sulfate Oxidation Process: Reacting sulfuric acid with iron scrap to obtain ferrous sulfate, which is used to remove arsenic and heavy metals, and then oxidized to obtain the product. The process is similar to that of iron oxide yellow.
Preparation methods include wet and dry methods. Wet method products have small crystallites, soft grains, and are easier to grind, making them suitable for use as pigments. Dry method products have larger crystals and hard grains, making them suitable for use as magnetic materials, polishing grinding materials. The wet method involves reacting a certain amount of 5% iron(II) sulfate solution rapidly with an excess of sodium hydroxide solution (requiring an excess of 0.04 to 0.08 g/ml), allowing air to enter at room temperature to completely convert it into a red-brown iron(III) hydroxide colloid solution. Under the presence of metal iron, iron(II) sulfate reacts with oxygen in the air to form iron(III) oxide (i.e., iron red), which deposits on the crystal nucleus. The sulfate in the solution then reacts with the metal iron to regenerate iron(II) sulfate, which is then oxidized by air to iron red and continues to deposit, repeating this cycle until the entire process is complete, forming iron oxide red. The dry method involves reacting iron sheets with nitric acid to form iron(II) nitrate, cooling and crystallizing, dehumidifying, grinding, and then calcining at 600 to 700°C for 8 to 10 hours, followed by washing, drying, and grinding to produce iron oxide red products. It can also be made from iron oxide yellow by calcining at 600 to 700°C. The 4Fe(NO3")3 equals" 或者 "Three equals△=2Fe2O3+12 NO2↑+3O2↑Fe2O3+n H2O==△==Fe2O3+nH2O
Main Use
Used for coloring in paints, rubber, plastics, and construction, it is an inorganic pigment that serves as a rust-preventive pigment in the paint industry. It is also used as a coloring agent in rubber, artificial marble, ground terrazzo, plastics, asbestos, synthetic leather, leather polish paste, and as a filler. Additionally, it is used as a polishing agent for precision instruments, optical glass, and as an ingredient in the manufacture of magnetic materials such as ferrites.
Used in the electronic industry, communication equipment, televisions, computers, etc. Magnetic raw materials and output transformers, switch power supplies, and ferrites for high U and high UQ, etc.
Used as an analytical reagent, a catalyst, and a polishing agent, and also as an ingredient in pigments;
For the coating of various tablet and pill drugs
Used as magnetic materials, pigments, and for the production of reducing agents, polishing agents, and catalysts; used for coloring in tablets and capsules.
Used as a rust-proof paint pigment. Because the mica iron oxide rust-proof paint made from this product has good water-resistant properties and excellent rust-proof performance, it can replace red lead.
Erythrosine. Used in red bean rice and konjac powder food in Japan. Identified when bananas with a cut in the stem that has been treated with a preservative. More commonly used in the United States for cat food, dog food, and packaging materials.
Inorganic red pigments are mainly used for transparent coloring of coins, and also for coloring in paints, inks, and plastics.
Widely used in the painting, rubber, plastic cosmetics, building precision grinding materials, precision hardware instruments, optical glass, enamel, educational supplies, leather, magnetic alloy and high-grade alloy steel coloring; mainly used as magnetic materials, pigments, polishing agents, catalysts, etc., also used in telecommunications, instrument industry; mainly used as magnetic materials, pigments, polishing agents, catalysts, etc., also used in telecommunications, instrument industry inorganic red pigment.
