Iron
Iron is an element of the side subgroup of the eighth group of the fourth period of the periodic system of chemical elements with atomic number 26. It is designated by the symbol Fe (lat. Ferrum). One of the most common metals in the earth's crust (second place after aluminum).
The simple substance iron (CAS number: 7439-89-6) is a malleable silver-white metal with high chemical reactivity: iron quickly corrodes at high temperatures or high humidity in the air. Iron burns in pure oxygen, and in a finely dispersed state it spontaneously ignites in air.
In fact, iron is usually called its alloys with a low impurity content (up to 0.8%), which retain the softness and ductility of the pure metal. But in practice, alloys of iron with carbon are more often used: steel (up to 2.14 wt.% carbon) and cast iron (more than 2.14 wt.% carbon), as well as stainless (alloy) steel with additions of alloying metals (chrome, manganese, nickel, etc.).
The combination of specific properties of iron and its alloys make it “metal No. 1” in importance for humans.
In nature, iron is rarely found in its pure form; most often it is found in iron-nickel meteorites. The abundance of iron in the earth's crust is 4.65% (4th place after O, Si, Al). Iron is also believed to make up most of the earth's core.
origin of name
There are several versions of the origin of the Slavic word “iron” (Belarusian zheleza, Ukrainian zalizo, Old Slavic zhelezo, Bulgarian zhelyazo, Serbo-Croatian zhejezo, Polish żelazo, Czech železo, Slovenian železo). One of the etymologies connects Praslav *želězo with the Greek word χαλκός, which meant iron and copper, according to another version *želězo is cognate with the words *žely “turtle” and *glazъ “rock”, with a common seme “stone”.
The third version assumes an ancient borrowing from an unknown language. The Romance languages (Italian ferro, French fer, Spanish hierro, Port ferro, Roman fier) continue Lat. ferrum. Latin ferrum (< *ferzom) is most likely borrowed from some eastern language, most likely from Phoenician. Wed. Hebrew barzel, Sumerian barzal, Assyrian parzilla.Germanic languages borrowed the name iron (Gothic eisarn, English iron, German.
Eisen, Netherlands ijzer, date jern, Swedish järn) from Celtic. The pre-Celtic word *isarno- (> Old Irish iarn, Old Brett hoiarn) probably goes back to Proto-I.e. *h1esh2r-no- “bloody” with the semantic development “bloody” > “red” > “iron”. According to another hypothesis, this word goes back to the ancestral i.e. *(H)ish2ro- “strong, holy, possessing supernatural power.”
The ancient Greek word σίδηρος may have been borrowed from the same source as the Slavic, Germanic and Baltic words for silver.
The name of natural iron carbonate (siderite) comes from the Latin. sidereus - starry; Indeed, the first iron that fell into the hands of people was of meteorite origin. Perhaps this coincidence is not accidental.
In particular, the ancient Greek word sideros (σίδηρος) for iron and the Latin sidus, meaning "star", probably have a common origin.
Receipt
In industry, iron is obtained from iron ore, mainly from hematite (Fe2O3) and magnetite (FeO Fe2O3). There are various methods for extracting iron from ores. The most common is the blast furnace process. The first stage of production is the reduction of iron with carbon in a blast furnace at a temperature of 2000 °C.
In a blast furnace, carbon in the form of coke, iron ore in the form of agglomerate or pellets, and flux (such as limestone) are fed from above, and are met by a stream of forced hot air from below. In the furnace, carbon in the form of coke is oxidized to carbon monoxide. This oxide is formed during combustion in a lack of oxygen. In turn, carbon monoxide reduces iron from the ore. To make this reaction go faster, heated carbon monoxide is passed through iron(III) oxide.
Flux is added to get rid of unwanted impurities (primarily silicates; such as quartz) in the mined ore. A typical flux contains limestone (calcium carbonate) and dolomite (magnesium carbonate). To remove other impurities, other fluxes are used. The effect of the flux (in this case calcium carbonate) is that when it is heated, it decomposes to its oxide. Calcium oxide combines with silicon dioxide to form slag - calcium metasilicate.
Slag, unlike silicon dioxide, is melted in a furnace. Slag, lighter than iron, floats on the surface - this property allows you to separate the slag from the metal. The slag can then be used in construction and agriculture. The molten iron produced in a blast furnace contains quite a lot of carbon (cast iron). Except in cases where cast iron is used directly, it requires further processing.
Excess carbon and other impurities (sulfur, phosphorus) are removed from cast iron by oxidation in open-hearth furnaces or converters. Electric furnaces are also used for smelting alloy steels. In addition to the blast furnace process, the process of direct iron production is common. In this case, pre-crushed ore is mixed with special clay, forming pellets. The pellets are fired and treated in a shaft furnace with hot methane conversion products, which contain hydrogen.
Hydrogen easily reduces iron without contaminating the iron with impurities such as sulfur and phosphorus, which are common impurities in coal. Iron is obtained in solid form and is subsequently melted in electric furnaces.
Chemically pure iron is obtained by electrolysis of solutions of its salts.
Source: http://edu.glavsprav.ru/info/fe/
Obtaining iron from ores. Direct iron intake. Recovery of iron from ores. Obtaining sponge iron. | mtomd.info
direct iron production processes we mean such chemical, electrochemical or chemical-thermal processes that make it possible to obtain metallic iron in the form of a sponge, crust or liquid metal directly from ore, bypassing a blast furnace. Such processes are carried out without consuming metallurgical coke, fluxes, or electricity (for the preparation of compressed air), and also make it possible to obtain very pure metal.
Methods for direct production of iron have been known for a long time. More than 70 different methods have been tested, but only a few have been implemented and, moreover, on a small industrial scale.
In recent years, interest in this problem has grown, which is associated, in addition to the replacement of coke with other fuels, with the development of methods for deep enrichment of ores, ensuring not only a high iron content in concentrates (7072%), but also its almost complete release from sulfur and phosphorus.
Production of sponge iron in shaft furnaces
When sponge iron is obtained, the mined ore is enriched and pellets are obtained. Pellets from bunker 1 through screen 2 enter box 10 of the charge filling machine and from there into shaft furnace 9, which operates on the countercurrent principle.
The spillage from the pellets falls into hopper 3 with a briquetting press and again enters screen 2 in the form of pellets.
To restore iron from pellets, a mixture of natural and blast furnace gases is supplied to the furnace through pipeline 8, subjected to conversion in unit 7, as a result of which the mixture decomposes into hydrogen H2 and carbon monoxide CO.
Installation for direct reduction of iron from ores and production of metallized pellets
In the reduction zone of furnace B, a temperature of 1000-1100 0C is created, at which H2 and CO reduce the iron ore pellets to solid sponge iron. iron in pellets reaches 9095%. To cool the iron pellets, air is supplied through pipeline 6 to cooling zone 0 of the furnace. Cooled pellets 5 are delivered to conveyor 4 and are sent to steel smelting in electric furnaces.
Reduction of iron in a fluidized bed
Fine-grained ore or concentrate is placed on a grid through which hydrogen or other reducing gas is supplied at a pressure of 1.5 MPa. Under hydrogen pressure, ore particles are suspended, undergoing continuous movement and forming a “boiling”, “fluidized” layer. In the fluidized bed, good contact of the reducing gas with the iron oxide particles is ensured. For one ton of recovered powder, the hydrogen consumption is 600,650 m3.
Preparation of sponge iron in crucible capsules
Silicon carbide capsules with a diameter of 500 mm and a height of 1500 mm are used. The charge is loaded in concentric layers. The inside of the capsule is filled with a reducing agent - crushed solid fuel and limestone (1015%) to remove sulfur.
The second layer is reduced crushed ore or concentrate, scale, then another concentric layer of reducing agent and limestone.
The capsules installed on trolleys move slowly in a tunnel furnace up to 140 m long, where they are heated, held at 1200 0C and cooled for 100 hours.
Reduced iron is obtained in the form of thick-walled pipes, they are cleaned, crushed and ground, obtaining iron powder with an iron content of up to 99%, carbon - 0.10.2%.
Source: http://www.mtomd.info/archives/1834
What is iron ore made from?
Take a look around. One way or another, you are 100% likely to stumble upon something whose component is the Ferrum element. He is also iron. Even the phone, tablet or computer with which you are reading this article also contains iron.
Ferrum is the fourth most abundant element on our planet. Being so popular, it simplifies the process of own production as much as possible. Unfortunately, it is still not found in its pure form, so it will have to be extracted from ore. Fortunately, extracting it from minerals and obtaining pure “Fe” is much easier than, say, uranium or even aluminum.
In this article we will look at the question of what is made from iron ore, how iron is extracted from it and where it is used.
Properties of ores
Answering the question: what properties does iron ore have is not entirely simple. If only because the list of properties depends on the percentage of a given metal in the ore and the amount of foreign impurities. For example, red iron ore containing hematite (Fe2O3) contains as much as 70% of the total iron.
https://www.youtube.com/watch?v=ouHtL2Mu7dw
In general, by the way, only those where the ores contain 40% iron or more are considered viable iron mining. This figure really makes it clear that iron is widespread in the surrounding world many times more than other elements. For example, for the same uranium, its content in the ore in the amount of 2% would be considered an unprecedented success
But let's return to our red iron ore. When characterizing iron ore, we can say that red iron ore ranges from a powdery substance to a dense one.
Limonite (also known as brown iron ore) is also an iron ore, but it is a porous and friable rock containing significant proportions of phosphorus and manganese. Clay is often used as waste rock. Due to this, by the way, it is quite easy to extract iron. That’s why cast iron is often made from it.
Spar iron ore with siderite at its head is a rather rare mineral, which does not make it a production resource. It also contains quite a lot of clay.
Black-blue magnetic ores can be as rich in iron as red iron ore. But their main feature is, of course, the properties of magnetism. Let them be lost with a strong increase in temperature. Even though magnetic iron ore is much rarer than others, its benefits are obvious.
Methods for extracting iron from ore
Iron ore is most often obtained in blast furnaces. The principle of operation of this method is to reduce iron from its oxides using coal, in the form of coke. Coal, oxidized in a furnace under the influence of oxygen, turns into carbon monoxide (CO). Then, the carbon monoxide heated in the furnace reacts with iron oxide (Fe2O3), resulting in carbon dioxide molecules and reduced iron molecules.
The resulting iron is still not perfectly pure. In order to remove all ore impurities from it, flux is then used. Flux is called calcium or magnesium carbonates (in common parlance – limestone and dolomite). When heated to 1000 degrees Celsius, carbonates disintegrate into their oxides, releasing carbon dioxide.
CaCO3 → CaO+CO2
Next, calcium or magnesium oxide reacts with iron impurities (for example, with quartz)
CaO+SiO2 → CaSiO3
The resulting slag melts very easily in the furnace. It floats on the surface, which makes it quite easy to separate it from the iron. Such an iron melt is still not the cleanest due to the significant presence of carbon atoms (coal). An alloy of iron and carbon is called cast iron.
Iron is a fairly active element and therefore very susceptible to corrosion. Then, you should not leave items with a high iron content in the open air or in places with high humidity.
Iron mining in Russia and the world
In terms of iron ore production, Russia can boast only 5-6% of the global level. But as far as reserves for potential further production are concerned, this is a confident first place. 18% of the world's iron ore is located in Russia. In second and third place are Brazil and Australia. An honorable fourth place went to the “cohabitant in the USSR” - Ukraine, 11 percent.
In the Russian Federation, the largest iron ore deposit is the Kursk Magnetic Anomaly. By the way, it is the largest deposit on the entire planet. The reserves of raw iron lying there are estimated at 30 billion tons.
Application of iron
It is noteworthy that practically nothing is done or produced from Ferrum itself, in its chemically pure form, in the world. This element is very easily oxidized by reacting with oxygen or other elements.
So what is iron ore for? It's simple. Ferrum enriched with carbon (cast iron alloy) is a very, very popular material.
Cast iron can either serve as an independent unit for the manufacture of any things and objects, or be an intermediate link between iron and steel.
Steel is an alloy of iron, carbon and other elements. Iron should be at least 45%, carbon - from 0.02 to 2.14 percent. If it is above 2.14%, it is already cast iron. And steel, in its dozens of variations, is used almost everywhere these days.
Mechanical engineering, aviation, instrument making, space buildings, nuclear energy, medicine (there is even a term - surgical steel), weapons industry (both cold steel and firearms), agricultural equipment, construction products, etc.
Due to the popularity of steel, we can safely say that no metal on the periodic table is used as intensively and in such quantities on Earth as iron.
Indeed, there are simply countless areas for the production of iron ore products, as well as compounds and alloys based on Ferrum. However, in the future, at such a pace and scale of production, humanity may face two questions: what to do when the reserves of this metal in the bowels of our planet begin to dry up? And what to do with those giant pits all over the planet that remain after open-pit mining of iron ore?..
Source: https://geomix.ru/blog/minerals/chto-delayut-iz-zheleznoj-rudy/
Iron in the human body: why it is needed and why iron deficiency is dangerous
The iron contained in the human body is enough for a large nail. This is approximately 2.5–4.5 grams. It would seem quite a bit. Nevertheless, the influence of iron on many vital processes is enormous, and its deficiency (as well as excess) immediately affects our well-being and can lead to serious consequences.
The role of iron in the body: a trace element with an important mission
Iron has many functions. Here are the main ones:
- Transport of oxygen to tissues . Iron is part of hemoglobin, the protein that makes up red blood cells (erythrocytes). It is iron that is responsible for the capture of oxygen, after which red blood cells transport it to all organs and systems of the body. These same blood cells (and again with the help of iron!) pick up waste carbon dioxide and transport it to the lungs for disposal. Without iron, respiratory processes at the cellular level would simply be impossible.
- Metabolism . Iron in the human body is an integral part of many enzymes and proteins that are necessary for metabolic processes - the destruction and disposal of toxins, cholesterol metabolism, and the conversion of calories into energy. It also helps the body's immune system cope with aggressors.
It is not surprising that iron deficiency affects appearance, health and well-being.
With a deficiency of this element, the skin becomes pale and dry, hair becomes dull and weak, and nails become brittle. Non-healing ulcers appear in the corners of the lips, and very painful cracks appear on the hands and feet.
As the amount of iron in the body decreases, the state of health worsens - appetite disappears, many notice discomfort when swallowing. Sometimes tastes change in the strangest way, for example, a person really wants to chew chalk or chew paper.
People with iron deficiency experience constant loss of energy - they even wake up tired. The slightest physical exertion causes severe shortness of breath - this is due to the lack of oxygen. Other typical symptoms of iron deficiency are dizziness and even fainting, drowsiness, irritability, and memory impairment.
For people suffering from iron deficiency, constant colds and intestinal infections are typical. As we have already said, iron is directly involved in the work of the body’s defense system, and if it is deficient, the immune system cannot repel attacks of pathogenic bacteria in a timely manner.
These symptoms will probably seem very familiar to many. No wonder: according to WHO statistics, approximately 60% of the world's population has a lack of iron in the body, and in 30% the deficiency of this element is so great that we are talking about iron deficiency anemia - a condition in which the level of hemoglobin is significantly reduced.
Interesting fact
Iron deficiency anemia is the most common type of anemia, accounting for more than 90% of all cases.
Content norm, or How much iron do we “carry”?
As already mentioned, our body contains 2.5–4.5 g of iron, and its supply must be constantly replenished.
Women require more iron than men - this is due to monthly blood loss during menstruation, as well as some features of the hormonal system. On average, a woman should receive 15 mg of iron daily, and during pregnancy and lactation - 20 mg or even more.
Men need 10 mg of iron daily.
Children and adolescents under 18 years of age need to receive 5–15 mg of iron per day - the need for this element increases with age.
Important!
The modern human diet practically does not allow us to obtain sufficient amounts of iron from food. On average, we consume about 10–20% of our daily iron requirement. The rest can be replenished with the help of dietary supplements and vitamin complexes.
Nothing gives such an accurate idea of the level of iron in the body as a simple biochemical blood test, which can be done in any laboratory.
The normal iron level for men is from 11.64 to 30.43 µmol/l, for women - from 8.95 to 30.43 µmol/l. In newborn children, the normal level of iron in the blood is much higher - from 17.9 to 44.8 µmol/l. But by the end of the first year of life it drops to 7.16–17.9 µmol/l, and by puberty it reaches adult levels.
Lack and excess of iron in the human body: causes and consequences
Excess iron is much less common than iron deficiency. This situation often occurs with very high iron content in drinking water, with diseases of the liver and spleen, as well as with metabolic disorders.
Excess iron includes symptoms such as ongoing digestive disorders (flatulence, diarrhea and constipation, nausea and vomiting, heartburn), loss of strength and dizziness, and the appearance of pigmentation on the skin. If no measures are taken, complications may develop - arthritis, diabetes, liver diseases.
Some experts also believe that excess iron is one of the risk factors for the development of cancer.
Iron deficiency is diagnosed much more often. And, as a rule, it is caused by an unbalanced diet, poor in this element.
Other typical causes of iron deficiency in the body are its active consumption (during growth, pregnancy and lactation), blood loss due to injuries, operations, internal bleeding or heavy menstruation, gastritis, helminthic infestations and dysbiosis (due to these diseases the process is disrupted). iron absorption), lack of vitamins C and B12, without which iron cannot be absorbed, disorders of the thyroid gland and lead poisoning.
Decreased immunity caused by iron deficiency sooner or later leads to infectious diseases becoming chronic, and this is one of the main dangers of iron deficiency. Iron deficiency anemia is a significant risk factor for the development of heart failure and liver disease. Anemia is especially dangerous for pregnant women - mothers who suffered from it while carrying a child often give birth to children with congenital anemia.
How to raise iron levels?
Even if a blood test shows an iron deficiency in the body, you should not immediately run to the pharmacy for a mineral complex and consider that the issue is closed. It is necessary to consult a doctor, since a lack of iron in the body may indicate the presence of serious diseases in which iron absorption is impaired.
If iron deficiency in the body is caused by poor diet, it is easy to correct.
Diet . It is necessary to eat as many foods high in iron as possible. Its most valuable sources are red meat, offal (especially liver), oysters, eggs, nuts, legumes, apples, pomegranates, raisins, and figs.
You also need to supplement your diet with foods that contain vitamin C (sea buckthorn, rose hips, Brussels sprouts, citrus fruits) and vitamin B12 (fish and seafood), they are needed to ensure that incoming iron is absorbed.
It is better to limit the consumption of tea, coffee and soda, and avoid alcohol altogether.
Vitamin complexes . Taking additional vitamins is an effective way to prevent iron deficiency in the body. In addition to this element, the complex should include vitamins A, C, E and D, all B vitamins, as well as copper, manganese and zinc - this is the optimal composition of the “rescue team” for iron deficiency.
Dietary supplements . There are many dietary supplements for people suffering from iron deficiency. The most famous dietary supplement for improving the condition of anemia is, perhaps, hematogen, familiar to everyone from childhood. It is a sweet slab that resembles toffee and contains high amounts of albumin, a natural source of iron.
If there are no other reasons for iron deficiency in the body other than poor nutrition, an improvement can be achieved within a month or two with the help of diet, dietary supplements and vitamins. And to speed up the process, we recommend moving more - physical activity helps saturate tissues with oxygen and helps cope with fatigue and drowsiness - the first signs of iron deficiency.
Source: https://www.kp.ru/guide/zhelezo-v-organizme-cheloveka.html
Physical and chemical properties of iron
And the volume number is 26. The symbol is Fe (Latin “ferrum”). One of the most common metals in the earth's crust (second place after aluminum).
Physical properties of iron
Iron is a gray metal. In its pure form it is quite soft, malleable and viscous. The electronic configuration of the outer energy level is [Ar]3d64s2. In its compounds, iron exhibits oxidation states “+2” and “+3”. The melting point of iron is 1539C.
Iron forms two crystalline modifications: α- and γ-iron. The first of them has a body-centered cubic lattice, the second has a face-centered cubic lattice. α-Iron is thermodynamically stable in two temperature ranges: below 912 and from 1394C to the melting point.
Between 912 and 1394C γ-iron is stable.
The mechanical properties of iron depend on its purity - the content of even very small quantities of other elements in it. Solid iron has the ability to dissolve many elements in itself.
Chemical properties of iron
In humid air, iron quickly rusts, i.e. covered with a brown coating of hydrated iron oxide, which, due to its friability, does not protect iron from further oxidation. In water, iron corrodes intensely; with abundant access to oxygen, hydrate forms of iron (III) oxide are formed:
2Fe + 3/2O2 + nH2O = Fe2O3×H2O.
With a lack of oxygen or difficult access, mixed oxide (II, III) Fe3O4 is formed:
3Fe + 4H2O(v) ↔ Fe3O4 + 4H2.
Iron dissolves in hydrochloric acid of any concentration:
Fe + 2HCl = FeCl2 + H2.
Dissolution in dilute sulfuric acid occurs similarly:
Fe + H2SO4 = FeSO4 + H2.
In concentrated solutions of sulfuric acid, iron is oxidized to iron (III):
2Fe + 6H2SO4 = Fe2(SO4)3 + 3SO2 + 6H2O.
However, in sulfuric acid, the concentration of which is close to 100%, iron becomes passive and practically no interaction occurs. Iron dissolves in dilute and moderately concentrated solutions of nitric acid:
Fe + 4HNO3 = Fe(NO3)3 + NO +2H2O.
At high concentrations of nitric acid, dissolution slows down and iron becomes passive.
Like other metals, iron reacts with simple substances. Reactions between iron and halogens (regardless of the type of halogen) occur when heated. The interaction of iron with bromine occurs at increased vapor pressure of the latter:
2Fe + 3Cl2 = 2FeCl3;
2Fe + Br2 = 2FeBr3;
3Fe + 4I2 = Fe3I8.
The interaction of iron with sulfur (powder), nitrogen and phosphorus also occurs when heated:
Fe + S = FeS;
6Fe + N2 = 2Fe3N;
Fe + P = FeP;
2Fe + P = Fe2P;
3Fe + P = Fe3P.
Iron is capable of reacting with non-metals such as carbon and silicon:
3Fe + C = Fe3C;
Fe + Si = FeSi.
Among the reactions of interaction of iron with complex substances, the following reactions play a special role - iron is capable of reducing metals that are in the activity series to the right of it from salt solutions (1), reducing iron (III) compounds (2):
Fe + CuSO4 = FeSO4 + Cu (1);
Fe + 2FeCl3 = 3FeCl2 (2).
Iron, at elevated pressure, reacts with a non-salt-forming oxide - CO with the formation of substances of complex composition - carbonyls - Fe(CO)5, Fe2(CO)9 and Fe3(CO)12.
Iron, in the absence of impurities, is stable in water and in dilute alkali solutions.
Getting iron
The main method of obtaining iron is from iron ore (hematite, magnetite) or electrolysis of solutions of its salts (in this case, “pure” iron is obtained, i.e. iron without impurities).
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