sulfuric: FeO + H 2 SO 4 = FeSO 4 + H 2 O nitrogen: 3FeO + 10HNO 3 = 3Fe (NO 3) 3 + NO + 5H 2 O Fe 2 O 3 + CO = 2FeO + CO 2

They are used in the production of magnetic storage media (magnetic tapes for audio, video and computer equipment, floppy disks, hard disk drives).

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See what "Iron oxides" are in other dictionaries:

IRON OXIDES: FeO Fe2O3 and Fe3O4. Natural iron oxides (hematite and magnetite) are raw materials for iron production. They are used in the production of magnetic materials, as pigments, components of lining ceramics ... Big Encyclopedic Dictionary

IRON OXIDES: FeO, Fe2O3 and Fe3O4. Natural iron oxides (hematite and magnetite) are raw materials for iron production. They are used in the production of magnetic materials, as pigments, components of lining ceramics ... encyclopedic Dictionary

IRON OXIDES- water-insoluble compounds FeO, Fe203 and their mixture Fe304 (natural mineral magnetite), which are used for the production of cast iron, steel, ferrites, etc ... Great Polytechnic Encyclopedia

FeO, Fe2O3 and Fe3O4. Natural iron oxides (hematite and magnetite) are raw materials for iron production. They are used in the production of magnetic materials, as pigments, components of lining ceramics ... encyclopedic Dictionary

Water-insoluble iron compounds: black FeO (obsolete ferrous oxide), tnl 1368 °C; black Fe2O3 (obsolete ferrous oxide, in nature the mineral magnetite), tnl 1538 ° С; yellow, brown or dark red Fe3O4 (in nature, the mineral hematite or ... Big encyclopedic polytechnic dictionary

FeO oxide (wustite technique). In the crystalline there are vacant sites in the wustite lattice, and its composition corresponds to FexO, where x= 0.89 0.95; The equation for the temperature dependence of the decomposition pressure is: log p(O2, in mmHg) = 26730/T+ 6.43 (T > 1813 K);… … Chemical Encyclopedia

FeO, Fe2O3 and Fe3O4. Natural Zh. about. (hematite and magnetite) raw materials for iron production. They are used in the production of magicians, materials, as pigments, components of lining ceramics ... Natural science. encyclopedic Dictionary

OXIDES: FeO (black, mp 1369shC); Fe2O3 (from dark red to black violet or brown, mp 1565shC; mineral hematite, etc.); Fe3O4 (black, mp 1594shC; magnetite mineral). Natural iron oxides are raw materials in the production of iron, ... ... Modern Encyclopedia

See iron oxides... Chemical Encyclopedia

IRON OXIDES, one of three compounds that exist in three states: iron oxide (II) (ferrous oxide, FeO); iron(III) oxide (iron oxide, Fe2O3), which occurs naturally as HEMATITE; and ferrous oxide iron (Fe3O4), which ... ... Scientific and technical encyclopedic dictionary

INTRODUCTION

This work is devoted to the study of the properties of iron oxide (III) Fe 2O 3, also known as minerals: hematite ( ?-Fe 2O 3), limonite (Fe 2O 3H2O), is part of magnetite (FeOFe2 O 3).

The topic of the course work is of practical and theoretical interest. The project will be useful for enterprises synthesizing Fe substance 2O 3on an industrial scale.

The project is also useful as a collection of information about iron, some of its oxides, iron oxide (III) in particular, and the minerals it is a part of.

Goals to be achieved upon completion of the project: to collect the most complete information about iron oxide (III), to study its properties and methods of synthesis.

Project objectives:

Collect complete and up-to-date information on the topic.

To study the properties of iron and its oxide (III) Fe 2O 3on the basis of which to learn about the use of these substances.

In rocket modeling, it is used to obtain catalyzed caramel fuel, which has a burning rate 80% faster than conventional fuel.

It is the main component of iron minium (kolkotar).

2 Kolkotar

Kolkotar - brown mineral paint. Other names: Parisian or English red paint, caput mortuum vitrioli, crocus, iron minium; in alchemy, the red lion.

In terms of composition, kolkotar is more or less pure anhydrous iron oxide. Although anhydrous iron oxide occurs in nature in very large quantities (red iron ore, iron luster), valuable grades of this paint are produced artificially or obtained as a by-product during the extraction of Nordhausen acid from ferrous sulfate, as well as during the calcination of the main sulfuric iron salts released from solution in the preparation of iron sulphate from vitriol stone.

4.3 Preparation and synthesis

Fe 2O 3is formed upon calcination in air of all hydrates and oxygen compounds of iron, as well as Fe(NO 3)3and FeSO 4. So, for example, calcined for 2 hours. full flame Bunsen burner Fe(OH) 3, obtained by the method of G. Guttig and G. Garside.

Fe(OH) 3= Fe 2O3 + 3H 2O

According to D.N. Finkelstein, 100 g of Fe (NO 3)39H 2O is heated in a large porcelain crucible on an electric stove. At first, the salt melts quietly, forming a brown liquid, which gradually evaporates. At 121°, the liquid begins to boil, releasing constantly boiling 68% HNO3.

Gradually, the liquid begins to thicken and frequent stirring is necessary to avoid shocks and splashing. Starting from 130°, the liquid is continuously stirred with a porcelain spatula, and it thickens, forming a paste (without stirring, the liquid suddenly solidifies into a continuous mass). At 132°, the paste immediately crumbles into powder, continuing to release HNO3 vapors.

Without ceasing to mix, continue heating until completely dry; the whole process takes 20-25 minutes. The dry mass is triturated, transferred to a crucible and calcined in a muffle at 600-700°C for 8-10 hours. With sufficient purity of the initial iron nitrate, the resulting product meets the qualification x. h. Yield 95-98% theoretical, i.e. about 19 g.

To prepare a pure preparation, a calculated amount of a hot solution of oxalic acid is added to a solution of iron ferrous salt heated to a boil, and ferrous oxalic acid precipitates. It is filtered off, washed thoroughly with water, dried and calcined in the presence of air, continuously stirring. Yield 90-93% theoretical. The resulting preparation contains 99.79-99.96% Fe2O 3.

A solution of 500 g of Fe(NO 3)3 9H 2About in 2 liters of water. A not too strong current of NH is passed through a tube extending to the bottom of the pot. 3washed with alkali and water. From time to time, the liquid is mixed with a gas outlet tube.

At the end of the precipitation, the liquid is allowed to settle, the solution is decanted, and the precipitate is washed with hot water until NO is removed. 3in wash waters. Washed out Fe(OH) 3dried in porcelain cups, and then calcined for 5-6 hours. at 550-600°. Yield 96 g (96-97% theoretical).

When receiving Fe 2O 3, which serves as a raw material for the preparation of high-purity Fe, the initial iron nitrate must be exceptionally pure. By repeated recrystallization of Fe(NO 3)39H 2O Cleaves and Thompson obtained a preparation containing only 0.005% Si and less than 0.001% other impurities.

According to Brandt, it is most expedient to proceed from chemically pure iron. The latter is dissolved in HCl, the solution is treated with hydrogen sulfide when heated, filtered, and ferrous iron in the filtrate is oxidized to trivalent boiling with a small amount of HNO 3. The mixture is evaporated twice with concentrated HCl and, after dissolving the residue in an excess of dilute HCl, the solution is shaken several times with ether in a large separating funnel.

If the starting material contained Co, then the contents of the funnel are allowed to settle, the lower (aqueous) layer is drained through the tap, and a part by volume of the mixture obtained by shaking HCl (sp. w. 1.104) with ether is added to the ether extract remaining in the funnel. Shake vigorously, drain the bottom layer again and repeat the operation.

The purified ether extract is filtered, the ether is distilled off (or simply removed by heating on a water bath), and the remaining FeCl solution 3evaporated several times with HNO 3. The last evaporation is carried out with the addition of NH4NO 3.

Evaporation is expediently carried out in a flat porcelain cup.

After evaporation, a brittle salt mass remains, easily separated from the cup. It is ground in a mortar and moderately calcined in portions of 40-50 g in a platinum cup. The residue is mixed several times with dry ammonium carbonate and ignited again at low red heat, stirring frequently.

This operation is repeated until an approximately constant weight (exactly constant weight cannot be achieved, since a small amount of Fe 2O 3carried away by vapors (NH 4)2SO 3).

iron metal oxide mineral

CONCLUSION

The goals set at the beginning of the research work were fully achieved:

)Collected information about iron, its oxides and minerals:

Iron is a malleable, silvery-white metal with a high reactivity. In compounds, it exhibits oxidation states +2, +3, +6. Has oxides: Fe +2O, Fe 2+3O 3, Fe 3O 4 (Fe +2O Fe +32O 3). Iron(III) oxide Fe 2O 3in addition to being obtained synthetically, it can be found in deposits of natural ores. It is part of some minerals such as: hematite, limonite, magnetite.

)The properties of Fe 2O 3and conclusions about its application are made:

Substance Fe 2O 3it is used to obtain pure, slightly oxidizable iron by hydrogen reduction, as well as in electronic information carriers (due to magnetism), as a polishing agent (crocus red) for steel and glass, in the food industry and is the main component of kolkotar (since the compound is coloring) .

)Several methods of substance synthesis have been studied. The highest yield of the product is 98% of theoretical. This result can be achieved by the method of D.N. Finkelstein, by heating Fe(NO 3)39H 2O in a large porcelain crucible on an electric stove with constant stirring.

BIBLIOGRAPHY

1) Ripan R. Inorganic chemistry: In 2 volumes / R. Ripan, I. Chetyanu; Transl. with rum. D.G. Batyra, Kh.M. Khariton; Ed. IN AND. Spitsyna, I.D. Collie. - M .: Publishing house "Mir" 1972. - 2 volumes.

)Knunyants I.L. Brief chemical encyclopedia: In 5 volumes / Ed. count I.L. Knunyants (responsible editor) and others - M .: Publishing house "Soviet Encyclopedia", 1967 - 5 vols.

)Lidin, R.A. Chemical properties of inorganic substances: textbook. allowance for universities / R.A. Lidin, Molochko, L.L. Andreeva. Ed. R.A. Lidina.- M.: Chemistry, 2000 - 480 p.

)Nekrasov B.V. Fundamentals of General Chemistry T. I. ed. 3rd, rev. and additional Publishing house "Chemistry", 1973 - 656 p.

) Remy G. Course of inorganic chemistry in 2 volumes / G. Remy; A.P. Grigorieva, A.G. Rykov; Ed. A.V. Novoselova. - M.: Mir Publishing House, 1966 - 2 vols.

)Paffengolts K.N. Geological Dictionary: in 2 volumes / Ed. com. K.N. Paffengolts (responsible editor), L.I. Borovikov, A.I. Zhamaida, I.I. Krasnov and others - M .: Nedra Publishing House, 1978 - 2 vols.

) Efimov A.I. Properties of inorganic compounds. Directory / A.I. Efimov and others - L .: Chemistry, 1983 - 392 p.

) Brower G. Guide to inorganic synthesis: in 6 volumes. Per. from German / Ed. G Brouwer. - M.: Mir Publishing House, 1985 - 6 vols.

)Karyakin Yu.V. Pure chemical reagents / Yu.V. Karyakin, I.I. Angels. - M.: State scientific and technical publishing house of chemical literature, 1955 - 585 p.

)Klyuchnikov N.G. Workshop on inorganic synthesis. - M .: Publishing house "Enlightenment", 1979 - 271 p.

) Terentyeva E.A. Inorganic syntheses: In 2 volumes / Per. from English. E.A. Terentieva, ed. DI. Ryabchikov, - M .: Publishing house of foreign literature, 1951 - 2 volumes.

) Glinka N.L. General Chemistry: Textbook for High Schools. - 23rd ed., Rev. / Ed. V.A. Robinovich. - L .: Chemistry 1983-704 p .: ill.

)Zakharov L.N. The beginning of laboratory work techniques. - L.: Chemistry, 1981 - 192 p.

)Spitsyn V.I. Inorganic chemistry. Part I: Textbook - M.: MGU Publishing House, 1991 - 480 p.: ill.

)Rabinovich V.A. Brief chemical reference book. - L .: Chemistry, 1977.

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) Workshop on General and Inorganic Chemistry / Ed. Vorobieva A.A., Drakina S.I. - M.: Chemistry, 1984.

) Zharsky I.M., Novikov G.I. Physical research methods in inorganic chemistry. - M.: Higher school, 1988.

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) Isidorov V.A. Ecological chemistry. - St. Petersburg: Himizdat, 2001.

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Author Chemical Encyclopedia b.b. I.L.Knunyants

IRON OXIDES . Oxide FeO (in technology - wustite). In the crystalline the wustite lattice has vacant sites, and its composition corresponds to the formula Fe x O, where x = 0.89-0.95; the equation for the temperature dependence of the decomposition pressure: lg p (O 2, in mm Hg) \u003d - 26730 / T + 6.43 (T\u003e 1813 K); see also table. Practically insoluble in water, freely soluble in acids, alkali solutions. Easily oxidized; pyrophoric. After calcination, the reactivity and pyrophoricity of FeO decrease. In nature - an extremely rare mineral iotsit. Obtained by the reduction of Fe 2 O 3 with hydrogen or CO or by calcination in an atmosphere of N 2 2FeC 2 O 4 * 3H 2 O. Fe 2 O 3 sesquioxide exists in three polymorphic modifications: the most stable a (hematite mineral), g (maghemite, oxymagnetite) and d (with a trigonal crystal lattice); transition temperatures a : g 677°C, g : d 777°C; D H 0 transition a: g 0.67 kJ / mol. For the modification a -Fe 2 O 3, the equation for the temperature dependence of the decomposition pressure: lg p (O 2, in mm Hg) \u003d - 10291 / T + 5.751gT - 1.09 * 10 - 3 T -0.75 * 10 5 T - 2 - 12.33; soluble in hydrochloric and sulfuric acids, slightly - in HNO 3; paramagnet, Neel point 953 K. Modifications g - and d -Fe 2 O 3 are ferrimagnetic; g -Fe 2 O 3 is formed by low-temperature oxidation of Fe 3 O 4 and Fe, d -Fe 2 O 3 can be obtained by hydrolysis and oxidation of solutions of Fe (II) salts. Oxide Fe (II, III) - a compound of the formula Fe 3 O 4, or FeO * Fe 2 O 3, Fe II (Fe III O 2) 2 (magnetite mineral), decomposes when heated; at 627 ° C a-form passes into b; the equation for the temperature dependence of the decomposition pressure: lgp (O 2, in mm Hg) \u003d - 33265 / T + 13.37 (T > 843 K); ferrimagnet, Curie point 900 K; has a high electrical conductivity. Soluble in acids to form Fe(II) and Fe(III) salts; When heated in air, it oxidizes to Fe 2 O 3 . Obtained by the action of water vapor on hot iron, the reduction of Fe 2 O 3, the oxidation of FeO. IRON OXIDES about. corresponds to a number of hydroxides. Hydroxide Fe (OH) 2 is formed by the action of alkali on aqueous solutions of Fe (II) salts; rapidly oxidized to FeO(OH). Solubility in water 0.00015 g per 100 g (18 ° C), soluble in acids, alkali solutions with the formation of hydroxoferrates (II), for example Na 2, and NH 4 Cl solutions. Fe (III) hydroxides form in nature a number of brown iron ore: hydrohematite Fe 2 O 3 * 0.1H 2 O (solid solution of water in hematite), turite 2Fe 2 O 3 * H 2 O (thin mechanical mixture of goethite and hydrohematite), goethite a -FeO (OH), or Fe 2 O 3 * H 2 O, lepidocrocite g -FeO (OH), hydrogoethite 3Fe 2 O 3 * 4H 2 O, limonite 2Fe 2 O 3 * 3H 2 O, xanthosiderite Fe 2 O 3 * 2H 2 O and limnite Fe 2 O 3 * 3H 2 O (solid solutions of water in goethite).

Limnit coincides in composition with the arts. hydrogel Fe(OH) 3 obtained by precipitation with alkali from solutions of Fe(III) salts. When calcined, Fe hydroxides are converted into a -Fe 2 O 3 . Fe(OH) 3 hydroxide is a very weak base; amphoterene, when combined with alkalis or basic oxides, they form salts of ferrous acid HFeO 2 not isolated in the free state - ferrates (III), or ferrites, for example NaFeO 2 . When Fe (OH) 3 is oxidized in an alkaline medium with strong oxidizing agents, salts of a non-existent iron acid H 2 FeO 4 (FeO 3 trioxide is also unknown) are formed - ferrates (VI), for example K 2 FeO 4 - red-violet crystals; at 120-200 °C they decompose into Fe 2 O 3 , M 2 O and O 2 ; stronger oxidizing agents than KMnO 4 . Natural oxides and hydroxides of Fe - raw materials in the production of Fe, natural and synthetic - mineral pigments (see Iron mica, Iron oxide pigments, Iron minium, Mummy, Ocher, Umber); FeO - an intermediate product in the production of Fe and ferrites, a component of ceramics and heat-resistant enamels; a -Fe 2 O 3 - a component of lining ceramics, cement, thermite, will absorb. masses for cleaning gases, polishing material (crocus), are used to obtain ferrites; g -Fe 2 O 3 - working layer of magnetic tapes; Fe 3 O 4 - material for electrodes in the electrolysis of alkali metal chlorides, a component of the active mass of alkaline batteries, colored cement, lining ceramics, thermite; Fe (OH) 2 - intermediate product in the preparation of IRON OXIDES o. and active mass of iron-nickel batteries; Fe(OH) 3 - a component of the absorbent mass for gas purification, a catalyst in organic synthesis.

Chemical encyclopedia. Volume 2 >>

IRON OXIDES Oxide FeO (in technology - wustite). In the crystalline the wustite lattice has vacant sites, and its composition corresponds to the f-le Fe x O, where x = 0.89-0.95; ur-tion of the temperature dependence of the decomposition pressure: lg p (O 2, in mm Hg) \u003d - 26730 / T + 6.43 (T\u003e 1813 K); see also table. Practically insoluble in water, very soluble. in to-ta, solutions of alkalis. Easily oxidized; pyrophoric. After calcining the chem. the activity and pyrophoricity of FeO decrease. In nature - an extremely rare mineral iotsit. Obtained by the reduction of Fe 2 O 3 with hydrogen or CO or by calcination in an atmosphere of N 2 2FeC 2 O 4 .3H 2 O. Fe 2 O 3 sesquioxide exists in three polymorphic modifications: max. stable a (mineral hematite), g (maghemite, oxymagnetite) and d (with a trigonal crystal lattice); transition temperatures a: g 677°C, g: d 777°C; DH 0 transition a: g 0.67 kJ/mol. For the a-Fe 2 O 3 modification, the equation for the temperature dependence of the decomposition pressure: lg p (O 2, in mm Hg) \u003d - 10291 / T + 5.751gT - 1.09.10 - 3 T -0.75.10 5 T - 2 - 12.33; sol. in hydrochloric and sulfuric acids, weakly in HNO 3; paramagnet, Neel point 953 K. Modifications of g- and d-Fe 2 O 3 are ferrimagnetic; g-Fe 2 O 3 is formed during low-temperature oxidation of Fe 3 O 4 and Fe, d-Fe 2 O 3 m. b. obtained by hydrolysis and oxidation of solutions of Fe (II) salts. Fe(II,III) oxide - Comm. f-ly Fe 3 O 4, or FeO.Fe 2 O 3, Fe II (Fe III O 2) 2 (mineral magnetite), when heated. decomposing; at 627 °C, the a-form transforms into b; ur-tion of the temperature dependence of the decomposition pressure: lgp (O 2, in mm Hg. Art.) \u003d - 33265 / T + 13.37 (T > 843 K); ferrimagnet, Curie point 900 K; has a high electrical conductivity. Solv. in to-tah with the formation of salts Fe (II) and Fe (III), calcined at 1200-1300 ° C prir. magnetite is practically insoluble. in to-ta and their mixtures. When loading in air it is oxidized to Fe 2 O 3 . Obtained by the action of water vapor on hot iron, the reduction of Fe 2 O 3, the oxidation of FeO. J. o. corresponds to a number of hydroxides. Hydroxide Fe (OH) 2 is formed by the action of alkali on Fe (II) salts; rapidly oxidized to FeO(OH). Solution in water 0.00015 g per 100 g (18°C), sol. in to-tah, solutions of alkalis with the formation of hydroxoferrates (II), for example. Na 2 , and solutions NH 4 Cl. Fe (III) hydroxides form in nature a number of brown iron ore: hydrohematite Fe 2 O 3 .0.1H 2 O (solid solution of water in hematite), turite 2Fe 2 O 3 .H 2 O (fine mechanical mixture of goethite and hydrohematite ), goethite a-FeO(OH), or Fe 2 O 3 .H 2 O, lepidocrocite g-FeO(OH), hydrogoethite 3Fe 2 O 3 .4H 2 O, limonite 2Fe 2 O 3 .3H 2 O, xanthosiderite Fe 2 O 3 .2H 2 O and limnite Fe 2 O 3 .3H 2 O (solid solutions of water in goethite).

Limnit coincides in composition with the arts. hydrogel Fe (OH) 3 obtained by precipitation with alkali from solutions of Fe (III) salts. When calcined, Fe hydroxides are converted into a-Fe 2 O 3 . Fe(OH) 3 hydroxide is a very weak base; amphoterene, when combined with alkalis or basic oxides, they form salts not isolated in free. in the state of ferrous to-you HFeO 2 - ferrates (W), or ferrites, e.g. NaFeO 2 . When Fe (OH) 3 is oxidized in an alkaline environment, strong oxidizing agents form salts of a non-existent iron to-you H 2 FeO 4 (FeO 3 trioxide is also unknown) - ferrates (VI), for example. K 2 FeO 4, - red-violet crystals; at 120-200 °C they decompose into Fe 2 O 3 , M 2 O and O 2 ; stronger oxidizing agents than KMnO 4 . Natural oxides and hydroxides of Fe - raw materials in the production of Fe, natural and synthetic - miner. pigments (see Iron mica, Iron oxide pigments, Minium iron, Mummy, Ocher, Umber); FeO - int. a product in the production of Fe and ferrites, a component of ceramics and heat-resistant enamels; a-Fe 2 O 3 - a component of lining ceramics, cement, thermite, will absorb. masses for cleaning gases, polishing material (crocus), are used to obtain ferrites; g-Fe 2 O 3 - working layer of magn. tapes; Fe 3 O 4 - material for electrodes in the electrolysis of alkali metal chlorides, a component of the active mass of alkaline batteries, colored cement, lining ceramics, thermite; Fe(OH) 2 -intermediate. product upon receipt J. o. and active mass of iron-nickel batteries; Fe(OH) 3 - a component of the absorption mass for gas purification, a catalyst in the org. synthesis. Lit.: see at Art. Iron. E. F. Wegman. Chemical encyclopedia. - M.: Soviet Encyclopedia Ed. I. L. Knunyants 1988

E-172 Iron oxides and hydroxides- food additive, dye.

Characteristic:

Iron oxides are inorganic pigments, which are chemical compounds of iron and oxygen. additive in the food industry E-172 used as a dye for coloring foodstuffs yellow, orange, red, brown and black. In total, 16 types of iron oxides and hydroxides are known. However, in the food industry, 3 forms of oxides are used to give products different shades: E-172(i) - Iron oxide (II,III) - a complex oxide that simultaneously contains iron (II) and iron (III) ions. It has the chemical formula Fe3O4 and occurs naturally as the mineral magnetite. Paints black. E-172(ii) - Iron oxide (III) with the chemical formula Fe2O3. It occurs naturally as the mineral hematite. In common parlance - rust. Colors red. E-172(iii) Iron(II) oxide with the chemical formula FeO. It occurs naturally as the mineral wustite. Colors yellow. They are readily soluble in concentrated inorganic acids, insoluble in water, organic solvents, vegetable oils. Very good resistance to light, heat and alkalis, good resistance to fruit acids. Iron oxides are found in nature, but in the food industry, to obtain an additive E-172 use the method of calcination of oxides of iron (II) and (III) or by the interaction of iron with water vapor at a high temperature below-570°C.

Application:

Iron oxides and hydroxides widely distributed in nature and used by people in various fields of production. WEIGHT iron oxides and hydroxides (E-172) are allowed for all QS foods. In the Russian Federation, the additive is allowed as a dye in food products according to TI in an amount according to TI (clauses 3.2.14, 3.11.3 SanPiN 2.3.2.1293-03). Iron oxides are used primarily for coloring dragees, ornaments and coatings at a dosage of about 0.1 g/kg. In addition to the food industry, iron oxides are used:

• in the metallurgical industry as a raw material for the production of metals;
• in the paint and varnish industry as a pigment in paints and coatings;
• in the chemical industry as catalysts;
• in the cosmetic industry to give the desired shades of cosmetic products (for coloring eyelash paint, foundation creams, make-up and powder);
• in pharmaceuticals for the manufacture of drugs that increase the level of hemoglobin, for coloring pharmaceuticals in the form of dragees, powders and creams. And iron oxides and hydroxides are used for coloring toilet soap, as pigments in painting, colored cement, as a component of lining ceramics.

  Impact on the human body:

  The maximum allowable daily intake of the supplement E-172 is 0.5 mg/kg of human body weight. In small doses, iron is good for the body (increases the level of hemoglobin in the blood). But with an overdose of iron, it can cause significant harm to health. High levels of iron in the body produce free radicals, which can lead to heart attacks and strokes. In addition, the accumulation of iron in the liver provokes liver cancer, but this is common in people with the genetic disease hemochromotosis. In a healthy body, subject to reasonable doses of iron intake, it does not cause any harm to the human body.

The human body contains about 5 g of iron, most of it (70%) is part of the hemoglobin in the blood.

Physical properties

In the free state, iron is a silvery-white metal with a grayish tint. Pure iron is ductile and has ferromagnetic properties. In practice, iron alloys are commonly used - cast irons and steels.

Fe is the most important and most common element of the nine d-metals of the secondary subgroup of group VIII. Together with cobalt and nickel, it forms the "iron family".

When forming compounds with other elements, it often uses 2 or 3 electrons (B \u003d II, III).

Iron, like almost all d-elements of group VIII, does not show a higher valency equal to the group number. Its maximum valency reaches VI and is extremely rare.

The most typical compounds are those in which the Fe atoms are in the +2 and +3 oxidation states.

Methods for obtaining iron

1. Commercial iron (in an alloy with carbon and other impurities) is obtained by carbothermal reduction of its natural compounds according to the scheme:

Recovery occurs gradually, in 3 stages:

1) 3Fe 2 O 3 + CO = 2Fe 3 O 4 + CO 2

2) Fe 3 O 4 + CO = 3FeO + CO 2

3) FeO + CO \u003d Fe + CO 2

The cast iron resulting from this process contains more than 2% carbon. In the future, steels are obtained from cast iron - iron alloys containing less than 1.5% carbon.

2. Very pure iron is obtained in one of the following ways:

a) decomposition of pentacarbonyl Fe

Fe(CO) 5 = Fe + 5CO

b) hydrogen reduction of pure FeO

FeO + H 2 \u003d Fe + H 2 O

c) electrolysis of aqueous solutions of Fe +2 salts

FeC 2 O 4 \u003d Fe + 2СO 2

iron(II) oxalate

Chemical properties

Fe - a metal of medium activity, exhibits general properties characteristic of metals.

A unique feature is the ability to "rust" in humid air:

In the absence of moisture with dry air, iron begins to noticeably react only at T > 150°C; when calcined, “iron scale” Fe 3 O 4 is formed:

3Fe + 2O 2 = Fe 3 O 4

Iron does not dissolve in water in the absence of oxygen. At very high temperatures, Fe reacts with water vapor, displacing hydrogen from water molecules:

3 Fe + 4H 2 O (g) \u003d 4H 2

The rusting process in its mechanism is electrochemical corrosion. The rust product is presented in a simplified form. In fact, a loose layer of a mixture of oxides and hydroxides of variable composition is formed. Unlike the Al 2 O 3 film, this layer does not protect the iron from further destruction.

Types of corrosion

Corrosion protection of iron

1. Interaction with halogens and sulfur at high temperature.

2Fe + 3Cl 2 = 2FeCl 3

2Fe + 3F 2 = 2FeF 3

Fe + I 2 \u003d FeI 2

Compounds are formed in which the ionic type of bond predominates.

2. Interaction with phosphorus, carbon, silicon (iron does not directly combine with N 2 and H 2, but dissolves them).

Fe + P = Fe x P y

Fe + C = Fe x C y

Fe + Si = FexSiy

Substances of variable composition are formed, since berthollides (the covalent nature of the bond prevails in the compounds)

3. Interaction with "non-oxidizing" acids (HCl, H 2 SO 4 dil.)

Fe 0 + 2H + → Fe 2+ + H 2

Since Fe is located in the activity series to the left of hydrogen (E ° Fe / Fe 2+ \u003d -0.44V), it is able to displace H 2 from ordinary acids.

Fe + 2HCl \u003d FeCl 2 + H 2

Fe + H 2 SO 4 \u003d FeSO 4 + H 2

4. Interaction with "oxidizing" acids (HNO 3 , H 2 SO 4 conc.)

Fe 0 - 3e - → Fe 3+

Concentrated HNO 3 and H 2 SO 4 "passivate" iron, so at ordinary temperatures the metal does not dissolve in them. With strong heating, slow dissolution occurs (without release of H 2).

In razb. HNO 3 iron dissolves, goes into solution in the form of Fe 3+ cations, and the acid anion is reduced to NO *:

Fe + 4HNO 3 \u003d Fe (NO 3) 3 + NO + 2H 2 O

It dissolves very well in a mixture of HCl and HNO 3

5. Attitude to alkalis

Fe does not dissolve in aqueous solutions of alkalis. It reacts with molten alkalis only at very high temperatures.

6. Interaction with salts of less active metals

Fe + CuSO 4 \u003d FeSO 4 + Cu

Fe 0 + Cu 2+ = Fe 2+ + Cu 0

7. Interaction with gaseous carbon monoxide (t = 200°C, P)

Fe (powder) + 5CO (g) \u003d Fe 0 (CO) 5 iron pentacarbonyl

Fe(III) compounds

Fe 2 O 3 - iron oxide (III).

Red-brown powder, n. R. in H 2 O. In nature - "red iron ore".

Ways to get:

1) decomposition of iron hydroxide (III)

2Fe(OH) 3 = Fe 2 O 3 + 3H 2 O

2) pyrite roasting

4FeS 2 + 11O 2 \u003d 8SO 2 + 2Fe 2 O 3

3) decomposition of nitrate

Chemical properties

Fe 2 O 3 is a basic oxide with signs of amphoterism.

I. The main properties are manifested in the ability to react with acids:

Fe 2 O 3 + 6H + = 2Fe 3+ + ZH 2 O

Fe 2 O 3 + 6HCI \u003d 2FeCI 3 + 3H 2 O

Fe 2 O 3 + 6HNO 3 \u003d 2Fe (NO 3) 3 + 3H 2 O

II. Weak acid properties. Fe 2 O 3 does not dissolve in aqueous solutions of alkalis, but when fused with solid oxides, alkalis and carbonates, ferrites are formed:

Fe 2 O 3 + CaO \u003d Ca (FeO 2) 2

Fe 2 O 3 + 2NaOH \u003d 2NaFeO 2 + H 2 O

Fe 2 O 3 + MgCO 3 \u003d Mg (FeO 2) 2 + CO 2

III. Fe 2 O 3 - feedstock for iron production in metallurgy:

Fe 2 O 3 + ZS \u003d 2Fe + ZSO or Fe 2 O 3 + ZSO \u003d 2Fe + ZSO 2

Fe (OH) 3 - iron (III) hydroxide

Ways to get:

Obtained by the action of alkalis on soluble salts Fe 3+:

FeCl 3 + 3NaOH \u003d Fe (OH) 3 + 3NaCl

At the time of receipt of Fe(OH) 3 - red-brown mucosamorphous precipitate.

Fe (III) hydroxide is also formed during the oxidation of Fe and Fe (OH) 2 in humid air:

4Fe + 6H 2 O + 3O 2 \u003d 4Fe (OH) 3

4Fe(OH) 2 + 2Н 2 O + O 2 = 4Fe(OH) 3

Fe(III) hydroxide is the end product of hydrolysis of Fe 3+ salts.

Chemical properties

Fe(OH) 3 is a very weak base (much weaker than Fe(OH) 2). Shows noticeable acidic properties. Thus, Fe (OH) 3 has an amphoteric character:

1) reactions with acids proceed easily:

2) a fresh precipitate of Fe(OH) 3 is dissolved in hot conc. solutions of KOH or NaOH with the formation of hydroxo complexes:

Fe (OH) 3 + 3KOH \u003d K 3

In an alkaline solution, Fe (OH) 3 can be oxidized to ferrates (salts of iron acid H 2 FeO 4 not isolated in the free state):

2Fe(OH) 3 + 10KOH + 3Br 2 = 2K 2 FeO 4 + 6KBr + 8H 2 O

Fe 3+ salts

The most practically important are: Fe 2 (SO 4) 3, FeCl 3, Fe (NO 3) 3, Fe (SCN) 3, K 3 4 - yellow blood salt \u003d Fe 4 3 Prussian blue (dark blue precipitate)

b) Fe 3+ + 3SCN - \u003d Fe (SCN) 3 Fe (III) thiocyanate (blood red solution)

Characterization and obtaining

E172 is a food coloring that combines three forms of iron oxides. It is odorless and tasteless, looks like a powder or paste. Spectrum of shades - black, brown, red, orange, yellow. Iron oxides are found in the natural environment, but for industrial use, a synthetic method for obtaining E172 is used.

There are 16 forms of iron oxides, but only three are used in the food industry:

The substance is highly soluble in inorganic acids and insoluble in water, organic solvents and vegetable oils. Retains properties when exposed to light, heat, fruit acids and alkalis.

Purpose

Iron oxide is involved in the production of food, giving them the necessary shade. The substance serves as a durable pigment in paints. Acts as a raw material for the manufacture of metals. The additive is used in the cosmetic, pharmaceutical and chemical industries.

Impact on the health of the human body: benefits and harms

Additive E172 is not harmful to health if consumed within the established norm. No more than 0.5 mg of a substance per kilogram of weight can enter the body per day. Too much iron leads to the formation of free radicals, which can cause heart attack, myocardial infarction, and stroke.

In patients with hemochromotosis, the accumulation of iron can provoke the development of liver cancer. But the dye E172, which contains iron, once in a healthy body, is completely processed and excreted. Thus, it does not harm health if the prescribed dosage is observed.

Applications

The food industry includes the additive E172 in the composition of products in order to color them in the desired color. Often the dye is used to give a black tint to artificial caviar (especially in Russia).

Iron oxide is stained with:

• dragee, chocolate, sweets;
• baking mixes;
• meat and fish pate;
• pet food;
• confectionery;
• product decorations;
• dairy desserts.

Other applications of iron oxides:

• metallurgy (raw materials for the manufacture of metals);
• cosmetology (painting foundation, powder, eyelash dye, etc.);
• pharmaceuticals (coloring preparations in the form of creams, powders, dragees; for the production of drugs that increase hemoglobin);
• chemical industry (acts as a catalyst);
• paint and varnish production (pigment in the composition of coatings and paints).

Content in products according to regulations

Table. The content of the food additive E172 in products according to SanPiN 2.3.2.1293-03 dated 05/26/2008

food products	The maximum level of content of E172 in products
Flavored and/or fermented drinks with milk (cocoa, chocolate milk, drinking yogurt, whey-based drinks)
Dairy desserts (puddings, flavored or fruit yoghurts)
Jams, marmalade, jelly
Processed cheeses
Rind of mature cheeses
Desserts based on fats other than dairy
Edible ice (including popsicles and sherbet)
Canned or pasteurized fruits
Fruit-based pastes
Fresh fruits with a treated surface
Fruit-based desserts (including water-based fruit flavors)
candied fruit
Confectionery (including caramel, nougat, candies)
Breakfast cereals (including oatmeal), desserts based on cereals and starches (for example, rice pudding, tapioca)
Sweet sauces, decorations (e.g. for baking), non-fruit toppings
Rich bakery products (salty, sweet, spicy) and mixes
Smoked, dried, fermented and/or salted fish and fish products, including molluscs, crustaceans and echinoderms
Caviar and products from it, analogues of salmon fish
Edible casings (e.g. for sausages)
fresh eggs	According to the RFP
Sauces and similar products
Condiments and condiments
Ready-to-eat food snacks based on potatoes, starch, cereals and flour
Processed nuts, shelled nuts, mixed nuts
Broths and soups
Water-based and flavored drinks, including "sports", "energy", "electrolyte" and granules

Legislation

The use of dye E172 is allowed in almost all countries. It is used in Russia, Ukraine, European countries, USA, Canada and many other countries.