Composition and properties of iron ore. Iron ores

Right in the middle of the quarry there is a mountain of waste rock, around which all the ore containing iron was mined. Soon it is planned to blow it up in parts and remove it from the quarry.

First, I’ll tell you about the quarry itself. Lebedinsky GOK is the largest Russian enterprise for the extraction and processing of iron ore and has the largest iron ore mine in the world. The plant and quarry are located in Belgorod region, between the cities of Stary Oskol and Gubkin. View of the quarry from above. It is really huge and growing every day. The depth of the Lebedinsky GOK pit is 250 m from sea level or 450 m from the surface of the earth (and the diameter is 4 by 5 kilometers); groundwater, and if not for the operation of the pumps, it would have filled to the very top within a month. It is twice listed in the Guinness Book of Records as the largest quarry for the extraction of non-combustible minerals.

Some official information: Lebedinsky GOK is part of the Metalloinvest concern and is the leading producer of iron ore products in Russia. In 2011, the share of concentrate production by the plant in the total annual production of iron ore concentrate and sinter ore in Russia amounted to 21%. There are a lot of different types of equipment at work in the quarry, but the most noticeable, of course, are the multi-ton Belaz and Caterpillar dump trucks.

Each year, both plants included in the company (Lebedinsky and Mikhailovsky GOK) produce about 40 million tons of iron ore in the form of concentrate and sinter ore (this is not the volume of production, but enriched ore, that is, separated from waste rock). Thus, it turns out that on average about 110 thousand tons of enriched iron ore are produced per day at the two mining and processing plants. This baby transports up to 220 tons (!) of iron ore at a time.

The excavator gives a signal and he carefully reverses. Just a few buckets and the giant’s body is filled. The excavator gives the signal again and the dump truck drives off.

Recently, BelAZ trucks with a lifting capacity of 160 and 220 tons were purchased (until now, the loading capacity of dump trucks in quarries was no more than 136 tons), and the arrival of Hitachi excavators with a bucket capacity of 23 cubic meters is expected. (currently the maximum bucket capacity of mining excavators is 12 cubic meters).

Belaz and Caterpillar alternate. By the way, an imported dump truck transports only 180 tons. Dump trucks with such a large load capacity are new technology, currently supplied to mining and processing plants as part of the Metalloinvest investment program to increase the efficiency of the mining and transport complex.

The stones have an interesting texture, pay attention. If I’m not mistaken on the left, quartzite is the kind of ore that iron is extracted from. The quarry is full of not only iron ore, but also various minerals. They are generally of no interest for further processing on an industrial scale. Today, chalk is obtained from waste rock, and crushed stone is also made for construction purposes.

Every day, 133 units of basic mining equipment (30 heavy-duty dump trucks, 38 excavators, 20 drilling machines, 45 traction units) operate in the quarry of the Lebedinsky GOK.

Of course, I hoped to see spectacular explosions, but even if they took place that day, I still would not have been able to penetrate the quarry territory. This explosion is done once every three weeks. All equipment according to safety standards (and there is a lot of it) is removed from the quarry before this.

Lebedinsky GOK and Mikhailovsky GOK are the two largest iron ore mining and processing plants in Russia in terms of production volume. The Metalloinvest company has the world's second largest proven reserves of iron ore - about 14.6 billion tons. international classification JORС, which guarantees about 150 years of operational life at the current production level. So the residents of Stary Oskol and Gubkin will be provided with work for a long time.

You probably noticed from the previous photographs that the weather was not good, it was raining, and there was fog in the quarry. Closer to departure, it dissipated slightly, but still not much. I pulled out the photo as much as possible. The size of the quarry is certainly impressive.

Iron ore is loaded immediately into railway trains, into special reinforced cars that transport the ore from the quarry, they are called dump cars, their carrying capacity is 105 tons.

Geological layers from which one can study the history of the Earth's development.

From the top of the observation deck, the giant machines seem no bigger than an ant.

Then the ore is taken to the plant, where the process of separating the waste rock using the magnetic separation method takes place: the ore is crushed finely, then sent to a magnetic drum (separator), to which, in accordance with the laws of physics, everything that is iron sticks, and what is not iron is washed off with water. The resulting iron ore concentrate is then made into pellets and hot briquetted iron (HBI), which is then used to make steel. Hot briquetted iron (HBI) is one of the types of directly reduced iron (DRI). Material with a high (>90%) iron content, obtained using a technology other than blast furnace processing. Used as a raw material for steel production. High-quality (with a small amount of harmful impurities) substitute for cast iron and scrap metal. Unlike cast iron, HBI production does not use coal coke. The process of producing briquetted iron is based on processing iron ore raw materials (pellets) at high temperatures, most often through natural gas.

You can’t just go inside the HBI plant, because the process of baking hot briquetted pies takes place at a temperature of about 900 degrees, and sunbathing in Stary Oskol was not part of my plans).

Lebedinsky GOK is the only producer of HBI in Russia and the CIS. The plant began production of this type of product in 2001, launching a workshop for the production of HBI (HBI-1) using HYL-III technology with a capacity of 1.0 million tons per year. In 2007, LGOK completed the construction of the second stage of the HBI production workshop (HBI-2) using MIDREX technology with a production capacity of 1.4 million tons per year. Currently, the production capacity of LGOK is 2.4 million tons of HBI per year.

After the quarry, we visited the Oskol Electrometallurgical Plant (OEMK), which is part of the Metallurgical segment of the company. In one of the plant's workshops these steel blanks are produced. Their length can reach from 4 to 12 meters, depending on the wishes of customers.

Do you see a bunch of sparks? A piece of steel is cut off at that point.

An interesting machine with a bucket, called a bucket carrier, into which slag is poured during the production process.

In the neighboring workshop, OEMK grinds and polishes steel rods of different diameters, which were rolled in another workshop. By the way, this plant is the seventh largest enterprise in Russia for the production of steel and steel products. In 2011, the share of steel production at OEMK amounted to 5% of the total volume of steel produced in Russia, the share of rolled products production also amounted to 5%.

OEMK uses advanced technologies, including direct iron reduction and electric arc melting technology, which ensures metal production high quality, with reduced impurity content.

The main consumers of OEMK metal products on the Russian market are enterprises in the automotive, machine-building, pipe, hardware and bearing industries.

OEMK metal products are exported to Germany, France, the USA, Italy, Norway, Turkey, Egypt and many other countries.

The plant has mastered the production of long products for the manufacture of products used by the world's leading automobile manufacturers.

By the way, this is not the first time I have noticed women crane operators in such industries.

This plant has an almost sterile cleanliness, which is not typical for such industries.

I like the neatly folded steel rods.

At the customer's request, a sticker is attached to each product.

The sticker is stamped with the heat number and steel grade code.

The opposite end can be marked with paint, and tags with the contract number, country of destination, steel grade, heat number, size in millimeters, supplier name and weight of the package are attached to each package of finished products.

These products are the standards by which precision rolling equipment is adjusted.

And this machine can scan the product and identify microcracks and defects before the metal reaches the customer.

The company takes safety precautions seriously.

All water used in production is purified by recently installed state-of-the-art equipment.

This is a cleaning installation waste water plant. After processing, it is cleaner than in the river where it is dumped.

Technical water, almost distilled. Like any industrial water, you cannot drink it, but you can try it once, it is not dangerous to your health.

The next day we went to Zheleznogorsk, located in the Kursk region. This is where the Mikhailovsky GOK is located. The photo shows the complex of roasting machine No. 3 under construction. Pellets will be produced here.

$450 million will be invested in its construction. The enterprise will be built and put into operation in 2014.

This is a layout of the plant.

Then we went to the quarry of the Mikhailovsky GOK. The depth of the MGOK quarry is more than 350 meters from the surface of the earth, and its size is 3 by 7 kilometers. There are actually three quarries on its territory, as can be seen in the satellite image. One big and two smaller. In about 3-5 years, the quarry will grow so much that it will become one large unified one, and perhaps will catch up in size with the Lebedinsky quarry.

The quarry uses 49 dump trucks, 54 traction units, 21 diesel locomotives, 72 excavators, 17 drilling rigs, 28 bulldozers and 7 motor graders. Otherwise, ore production at MGOK is no different from LGOK.

This time we finally managed to get to the plant, where iron ore concentrate is converted into the final product - pellets. Pellets are lumps of crushed ore concentrate. Semi-finished product of metallurgical iron production. It is a product of the enrichment of iron-containing ores using special concentrating methods. Used in blast furnace production to produce cast iron.

Iron ore concentrate is used to produce pellets. To remove mineral impurities, the original (raw) ore is finely crushed and enriched in various ways. The process of making pellets is often called “pelletizing”. The charge, that is, a mixture of finely ground concentrates of iron-containing minerals, flux (additives that regulate the composition of the product), and strengthening additives (usually bentonite clay), is moistened and subjected to pelletization in rotating bowls (granulators) or pelletizing drums. They are the ones in the picture.

Let's come closer.

As a result of pelletization, nearly spherical particles with a diameter of 5÷30 mm are obtained.

It's quite interesting to watch the process.

Then the pellets are sent along a belt to the firing body.

They are dried and fired at temperatures of 1200÷1300° C in special installations - firing machines. Calcining machines (usually the conveyor type) are a conveyor of calcining carts (pallets) that move on rails. But the picture shows the concentrate that will soon end up in the drums.

In the upper part of the roasting machine, above the roasting carts, there is a heating furnace in which gaseous, solid or liquid fuel and the formation of coolant for drying, heating and roasting of pellets. There are roasting machines with cooling of pellets directly on the machine and with an external cooler. Unfortunately, we did not see this process.

The fired pellets acquire high mechanical strength. During firing, a significant portion of sulfur contaminants is removed. This is what the ready-to-eat product looks like).

Despite the fact that the equipment has been in service since Soviet times, the process is automated and there is no need to control it. large quantity personnel.

Iron is a common element in nature. Its content in the earth's crust is 4.2%. It only contains more oxygen - 49.7%, silicon - 26% and aluminum - 7.45%.

Ore minerals or ores are those mineral masses from which it is economically feasible to extract metals or a necessary element. In accordance with this iron ores are called rocks from which it is economically feasible to smelt iron. The constant change in economic conditions due to the development of ore beneficiation methods and the reduction in the cost of their transportation changes the idea of ​​iron ore, since the lower limit of the iron content in it is constantly decreasing.

An industrial ore deposit is considered to be an accumulation of ores that is economically feasible to develop. The profitability of this development increases with the increase in the capacity of the deposit, since investing in the construction of, for example, mines or quarries, housing, communications, is advisable only if the deposit is exploited for a sufficiently long time. Experience shows that the exploitation of the iron ore deposit is feasible and has a sustainable prospect with reserves of about 250-500 million tons.

Ore consists of ore and ore-forming minerals, gangue and impurities. The extracted element is found in the ore mineral.

Ore minerals of iron ores are oxides, carbonates of iron and some other compounds. The main ones are described below.

It has a chemical composition of Fe 2 O 3 - anhydrous iron oxide. Hematite contains 70% iron. The ore formed by hematite is called red ironstone and is the most common type of ore. It is usually characterized by a high iron content and a low content of harmful impurities. A typical deposit of hematite ores is Krivoy Rog.

Figure 1 - General view hematite mineral

It has a chemical composition of Fe 3 O 4 - magnetic iron oxide containing 72.4% iron. It differs from other industrial iron ore minerals in its magnetic properties, which are lost when heated above 570 o C. Magnetite is a mixed iron oxide FeO*Fe 2 O 3. Ores formed by magnetite are called magnetic iron ores or magnetites. They are less common than hematites, characterized by a high iron content, reduced reducibility, and often accompanied by sulfur.

Figure 2- Type of mineral magnetite

Hydrous iron oxides - Fe 2 O 3 *nH 2 O - depending on the value of n form various types oxides, but all ores formed by them are called brown iron ores. The following hydrous iron oxides are distinguished:

• n=0.1 - hydrohematite
• n=1 - goethite
• n=1.5 - lemonite, etc.

The most common brown iron ores based on limonite are 2Fe 2 O 3 * 3H 2 O, which are called limonite.

Brown iron ores are characterized by a low iron content, are friable, often accompanied by manganese and phosphorus, and have high porosity and reducibility.

Figure 3- Brown iron ore based on limonite

Siderite- has a chemical composition of FeCO 3 - iron carbonate. Contains 48.2% iron. The ore formed by siderite is called spar iron ore, or siderite. With significant amounts of clay impurities it can be called clay iron ore. Siderites are much less common than other ores. They are characterized by high reducibility, low iron content due to its insignificant content in the ore mineral and a large amount of waste rock. Under the influence of atmospheric moisture and oxygen, siderites can transform into brown iron ores, since the iron oxide (II) in the FeO*CO 2 molecule oxidizes and absorbs moisture. Therefore, there are deposits in which the upper layers of ore are brown iron ores, and the lower bedrock are siderites.

Figure 4

It has a chemical composition of FeTiO 3 - iron salt of titanic acid. Ilmenite contains 36.8% iron and 31.8% titanium. It is always found in intergrowths with ordinary magnetite, i.e. in the form of FeTiO 3 *Fe 3 O 4. The ores formed by ilmenite are called titanomagnetites.

Figure 5- General view of the mineral ilmenite

Titanium magnetite is a dense, difficult-to-reduce ore that produces thick and refractory titanium-containing slag. It has magnetic properties and is well enriched by magnetic separation. Often accompanied by vanadium.

Iron sulfide FeS 2 is found in nature in the form of the mineral pyrite or sulfur pyrite. It contains 46.6% iron. Iron ores do not form pyrite. It is used in chemical industry, where it is burned to separate the sulfur. Iron is oxidized and used in the form of pyrite cinders in the production of sinter.

Iron ore began to be mined by humans many centuries ago. Even then, the benefits of using iron became obvious.

Finding mineral formations containing iron is quite easy, since this element makes up about five percent earth's crust. Overall, iron is the fourth most abundant element in nature.

IN pure form it is impossible to find, iron is found in certain amounts in many types rocks. Iron ore has the highest iron content, the extraction of metal from which is the most economically profitable. The amount of iron it contains depends on its origin, the normal proportion of which is about 15%.

Chemical composition

The properties of iron ore, its value and characteristics directly depend on its chemical composition. Iron ore may contain different quantity iron and other impurities. Depending on this, there are several types:

• very rich, when the iron content in the ores exceeds 65%;
• rich, the percentage of iron in which varies from 60% to 65%;
• average, from 45% and above;
• poor, in which the percentage of useful elements does not exceed 45%.

The more by-products there are in iron ore, the more energy is needed to process it, and the less efficient the production of finished products is.

The composition of a rock can be a combination of various minerals, waste rock and other by-products, the ratio of which depends on its deposit.

Composition of iron ores of large deposits

Gap rock may also contain iron, but recycling it is not economically feasible. The most commonly found minerals are iron oxides, carbonates and silicates.

It should be noted that ferruginous rocks may contain a huge amount of harmful substances, among which are sulfur, arsenic, phosphorus and others.

Types of iron ores

Today, there are many types of iron ores, the characteristics and names of which depend on the composition.

The most common type found in nature is red iron ore, which is based on an oxide called hematite. This oxide contains an amount of iron exceeding 70%, and minimum quantity side impurities.

The physical state of this oxide can vary from powdery to dense.

Brown iron ore is an iron oxide containing water. It is often called limonite. It contains significantly less iron, the amount of which usually does not exceed a quarter. In nature, such iron ore is found in the form of loose, porous rock, with a significant content of manganese and phosphorus. Usually richly saturated with moisture, it contains clay as waste rock. Cast iron is very often made from it, despite the insignificant part of iron, since it is very easily processed.

Magnetic ores are distinguished by the fact that they are based on an oxide having magnetic properties, but with strong heating they are lost. The amount of this type of rock in nature is limited, but the iron content in it can be as good as red iron ore. Externally, it looks like solid black-blue crystals.

Spar iron ore is an ore rock based on siderite. Very often it contains a significant amount of clay. This type of rock is relatively difficult to find in nature, which makes it rarely used due to its low iron content. Therefore, it is impossible to classify them as industrial types of ores.

In addition to oxides, nature contains other ores based on silicates and carbonates. The amount of iron content in a rock is very important for its industrial use, but also important is the presence of beneficial by-products such as nickel, magnesium, and molybdenum.

Applications

The scope of application of iron ore is almost completely limited to metallurgy. It is used mainly for smelting cast iron, which is mined using open-hearth or converter furnaces. Today cast iron is used in various fields human life, including most types of industrial production.

Various iron-based alloys are no less used - the most wide application gained steel due to its strength and anti-corrosion properties.

Cast iron, steel and various other iron alloys are used in:

1. Mechanical engineering, for the production of various machines and devices.
2. Automotive industry, for the manufacture of engines, housings, frames, as well as other components and parts.
3. Military and missile industry, in the production of special equipment, weapons and missiles.
4. Construction, as a reinforcing element or construction of load-bearing structures.
5. Light and food industries, as containers, production lines, various units and devices.
6. Mining industry, as special machinery and equipment.

Iron ore deposits

The world's iron ore reserves are limited in quantity and location. Territories of accumulation of ore reserves are called deposits. Today, iron ore deposits are divided into:

1. Endogenous. They are characterized by a special location in the earth's crust, usually in the form of titanomagnetite ores. The shapes and locations of such inclusions are varied, they can be in the form of lenses, layers located in the earth's crust in the form of deposits, volcanic deposits, in the form various veins and other irregular shapes.
2. Exogenous. This type includes deposits of brown iron ores and other sedimentary rocks.
3. Metamorphogenic. Which include quartzite deposits.

Deposits of such ores can be found throughout our planet. The largest number of deposits is concentrated in the territory post-Soviet republics. Especially Ukraine, Russia and Kazakhstan.

Countries such as Brazil, Canada, Australia, USA, India and South Africa have large iron reserves. Moreover, in almost every country globe We have our own developed deposits, and if there is a shortage of them, the rock is imported from other countries.

Iron ore beneficiation

As stated, there are several types of ores. Rich ones can be processed directly after extraction from the earth's crust, others need to be enriched. In addition to the beneficiation process, ore processing includes several stages, such as sorting, crushing, separation and agglomeration.

Today there are several main methods of enrichment:

1. Flushing.

It is used to clean ores from by-products in the form of clay or sand, which are washed out using jets of water under high pressure. This operation allows you to increase the amount of iron content in low-grade ore by approximately 5%. Therefore, it is used only in combination with other types of enrichment.

1. Gravity cleaning.

Performed using special types suspensions, the density of which exceeds the density of waste rock, but is inferior to the density of iron. Under the influence gravitational forces by-products rise to the top, and iron falls to the bottom of the suspension.

1. Magnetic separation.

The most common beneficiation method, which is based on different levels of perception by ore components of the influence of magnetic forces. Such separation can be carried out with dry rock, wet rock, or in an alternate combination of its two states.

To process dry and wet mixtures, special drums with electromagnets are used.

1. Flotation.

For this method, crushed ore in the form of dust is dipped into water with the addition of a special substance (flotation reagent) and air. Under the influence of the reagent, the iron joins the air bubbles and rises to the surface of the water, while the waste rock sinks to the bottom. Components containing iron are collected from the surface in the form of foam.

In such compounds and in such quantities that it can be extracted from ores. economically profitable. The iron content in ores ranges from 25 to 70%. The profitability of using ore is determined, in addition to the properties of the ore itself, savings, by factors: a) the cost of ore mining; b) the prices of fuel in a given area (cheap fuel allows the processing of poorer ores), c) the proximity of sales markets and d) the height of freight for sea and rail delivery.

The quality of ore, in addition to the percentage of iron content in it, depends on: a) its purity, i.e., the quality and quantity of harmful impurities in it, b) the quality and composition of waste rock mixed with the ore and c) the degree of its ease of recovery.

The purity of ores depends on the amount of harmful impurities. The latter include: 1) sulfur, which is most often found in the form of sulfur pyrite (FeS 2), copper pyrite (Cu 2 S Fe 2 S 3), magnetic pyrite (FeS), occasionally in the form of lead luster (PbS), and also in the form of sulfate salts of calcium, barium and iron; 2) arsenic, which is most often found in the form of arsenic pyrite (FeS 2 ·FeAs 2) and löllingite (FeAs 2); 3) phosphorus, found in the form of phosphoric acid salts of Ca [apatite 3 Ca 3 (PO 4) 2 CaF 2 or 3 Ca 3 (PO 4) 2 CaCl 2], iron phosphate [the so-called vivianite Fe 3 (PO 4 ) 2 8H 2 O] and aluminum (wavelite ZAl 2 O 3 2P 2 O 3 12H 2 O); 4) copper, found in the form of copper pyrite (Cu 2 S Fe 2 S 3).

The amount of waste rock and the content of harmful impurities determines whether the ore should be sorted, washed, or enriched. Depending on the quality of the gangue ore, it may be either acidic or basic. Acid ores, so-called. quartz ores, contain excess silica and require fluxing with bases during smelting. Basic ores (containing an excess of bases in the waste rock) are divided into clay ores, which contain an excess of alumina in the mixture, calcareous, in which lime predominates, and talc ores, which contain a lot of magnesia in the waste rock. Sometimes there are ores that produce low-melting slag without fluxing; they are called self-melting.

The degree of easily reducible ores depends: 1) on the compound in which iron is found in the ore: silicates and titanates are more difficult to reduce than free iron oxide; 2) on the density of the ore and its degree of porosity. Ore recovery goes with that more energetic, the more porous it is and, therefore, accessible to gas penetration, and also if it contains volatile substances - water, carbon dioxide, organic impurities that are released when high temperature. By chemical composition Iron ores can be divided into 4 classes - ores containing: 1) anhydrous iron oxides, 2) hydrous iron oxides, 3) iron carbonate and 4) iron silicate.

I. Ores containing anhydrous iron oxides . 1) Magnetic iron ore, or magnetite, has the following properties: has a metallic luster, black color, gives a black streak; quite fragile; hardness 5.5-6.5; specific gravity 5-5.2; magnetic; crystallizes in a regular system, most often in the form of octahedra and cubes. In view of the fact that the relationship between nitrous oxide and ferric oxide can be different, it is more correct to depict its formula as follows: m FeО·n Fe 2 О 3 .

The ore of Mount Vysokaya (Nizhne Tagil district) is considered one of the best. The iron content in it is very high, on average 60%; Mn 1.0-1.5%; sulfur 0.02-0.03%; in terms of phosphorus content (0.04%) this is Bessemer ore. The composition of waste rock is characterized by a low ratio of SiO 2: Al 2 O 3, as a result of which the blast furnace slags of the Tagil plants differ sharply from the slags of American and Swedish blast furnaces. In this deposit there are outcrops of martite (a mineral resulting from the oxidation of Fe 3 O 4 into Fe 2 O 3). The actual ore reserve of Mount Vysokaya is determined to be 16,400,000 tons (according to the Geological Committee). Not far from the main deposit is the Lebyazhinsky mine, where the ore is highly phosphorous. The total reserve of ores, according to the Geological Committee, is 5,316,000 tons. The ore of Mount Blagodat, near Kushva (section - Fig. 1), differs from the Vysokogorsk one in richness, purity, and reducibility. The reserve of the richest ores is heavily depleted. Based on iron content, bedrock ore is divided into three grades: 1st grade 50-60% Fe, 2nd grade 40-50% and 3rd grade 20-40%. The sulfur content in the first two varieties is higher than in the highland varieties (up to 0.1%); the ore requires careful oxidizing roasting. Based on the phosphorus content, this ore can be considered Bessemer; manganese in it is on average about 0.5%. Barren feldspathic rock produces different attitude SiO 2: Al 2 O 3; as a result, some ores require basic flux (smelting on charcoal), others require acid flux; Some ores can be considered self-melting. Goroglagodat ore is more difficult to restore than Vysokogorsk ore, since it is a dense, unoxidized magnetic iron ore. It produces little fines when crushed. The possible reserve of the Goroblagodatsky district is determined (together with explored and actual) at 36,092,000 tons (data from the Geological Committee).

Mount Magnitnaya (Orenburg District) is a deposit very rich (like Vysokogorsk) in pure ores, but little used. The average Fe content is not less than 60% with an insignificant amount of carbon (Bessemer ore); In the upper horizons, sulfur deposits are very small, but as you go deeper into the depths, its amount increases significantly. The deposit also contains martite, as well as iron luster and red iron ore; sometimes - limonite. Possible ore reserves, according to the latest estimates by A.N. Zavaritsky, about 188580000 tons.

Of the secondary deposits in the area of ​​the Bogoslovsky plant, there are deposits of magnetic iron ore, which turns into martite and red iron ore. In addition to the Ural deposits, there are also deposits in the Karelian Autonomous Soviet Socialist Republic, Transcaucasia and Siberia. In the Pudozhgorsk field, on the eastern shore Lake Onega, the ore contains from 15 to 25% iron; the estimated reserve is estimated at 1 million tons (according to V.N. Lipin). With magnetic enrichment, it produces pure and rich concentrates (concentrates), which then need to be briquetted or agglomerated. These ores can produce excellent cast iron, equal to the best Swedish cast iron. The Dashkesan deposit in Transcaucasia is very large, unmatched in the area in terms of quantity and quality of ore. Due to its purity, this ore can be exported. The possible reserve of ore is determined by K. N. Paffengoltz at 43,750,000 tons. In Siberia there are: a) Telbeskoye and Sukharinskoye deposits in Altai; ore contains 35-63% (on average no more than 55%) iron; free from phosphorus; the reserve is estimated at 29,110,000 tons (data from the Geological Committee); b) Abakan deposit in the Minusinsk district, on the banks of the river. Ore Keni; ore contains 53-63% iron; the reserve is not known exactly, the estimated value is 25 million tons; c) Irbinskoye - in the valley of the Irba River; ore reserves over 25 million tons; iron contains 52-60%; in some places it becomes martite; part of the ore is rich in phosphorus (according to K. Bogdanovich). Thick deposits of magnetic iron ore are located in the area of ​​the Kursk magnetic anomaly.

The most significant foreign deposits are as follows. In northern Scandinavia (Swedish Lapland) there are colossal deposits: Kirunavara, Luosavara, Gelivara, Svappavara, etc. About 6 million tons of these ores are mined for export. Most of the ores are rich in phosphorus. The total reserve of ores of the Kirunavara and Luosavara deposits to the surface of the waters near Lake Vogt is estimated at 282 million tons, and to a depth of 300 m below the surface of the lake - 600-800 million tons. The Gelivara deposit is the largest in size, the southernmost of the Lapland ones, represents a series of lenticular ore strata covered with glacial deposits. An ore field up to 6 km long has been explored by drilling to a depth of more than 240 m. The ore contains slightly less phosphorus than Kirunavar ore; in some places accompanied by hematite (iron luster). A number of deposits are known in Sweden: Gränyesberg, Stryberg, Persberg, Norberg and Dannemura. The ore of the latter is distinguished by its purity in terms of phosphorus, containing 50-53% Fe. In the rest of Europe there are less significant deposits of magnetic iron ore - in Hungary, Saxony, Silesia, etc. North America can be pointed to large deposit, located near Lake Champlain; then - in the states New York, New Jersey, Pennsylvania and Cornwall County. Analyzes of magnetic iron ore from different deposits are given in Table. 1.

2) Hematite, Fe 2 O 3. Its varieties are iron luster, red iron ore, etc. Only red iron ore itself is of industrial importance (analyzes are given in Table 2).

Its crystals are rhombohedral, table-shaped and pyramidal; more often it occurs in continuous masses, shell-like, layered and scaly in composition and oolitic structure. Deposits of a stratal nature are accompanied in most cases by quartz waste rock (the ore is refractory), limestone, and feldspar. Phosphorus usually contains little; sometimes has an admixture of sulfur pyrites; impurities TiO 2 and Cr 2 O 3 are found. The dense variety is called red glass head, the earthy variety is called red iron ochre.

One of the most powerful deposits of red iron ores in the USSR is Krivoy Rog in Ukraine (section - Fig. 2), in which red iron ores are accompanied by an iron luster with ferruginous quartzite. The iron content in the ore is 50-70%. Ores poorer than 55% are almost never used for smelting, because they contain a lot of empty, highly siliceous rock and very few bases (CaO, MgO) and therefore require a huge amount of fluxes. The phosphorus content ranges from 0.01 to 0.10%; there is little manganese, sometimes only traces; there is very little sulfur (0.03-0.04%).

Ore, very diverse in physical properties, found in the form of crushed iron luster (powdery) or dense lumps (former Galkovsky mine). The reserve of ore with an iron content of more than 60% is determined at 210940000 tons (data from the Geological Committee). Krivoy Rog ores were exported abroad in the quantities indicated in table. 3.

Another deposit, called Korsak-Mogila, is located in the south, in the Mariupol district. The ore reserve is small, about 330,000 tons. Excellent iron luster, containing little phosphorus and sulfur, is found in the Cherdyn region of the Ural region; The main deposit has already been developed. In the Karelian Autonomous Soviet Socialist Republic, the Tulomozerskoe deposit is known; the ore is highly siliceous and must be beneficiated. Rich ores contain 57-60% Fe and are free of phosphorus and sulfur. No powerful deposits have been discovered in Siberia.

Of the foreign ones, the richest and most powerful is the deposit Lake Superior in the USA (between Lakes Michigan and Lake Superior) and in Canada. The reserve of rich ores is about 2 billion tons. The possible reserve of poorer ores requiring beneficiation is determined to be up to 65 billion tons. The iron content in these ores is on average about 50%; they are lighter than the Krivoy Rog ones; The manganese content is not high (from 0.3 to 0.6%), but sometimes highly manganese ores are found (4% Mn), then they always contain a lot of phosphorus. Based on phosphorus content, some ores can be classified as Bessemer (from 0.015 to 0.045%) and Nessemer (P content up to 0.4% or more). They contain little sulfur. In North America, there are also known ore deposits located in the Appalachian Mountains system, called “Clinton hematites.” The main mining takes place in the state of Alabama (up to 4 million tons of ore per year). The average iron content hovers around 38%. The ore reserve is estimated at 500 million tons, the probable reserve is 1.4 billion tons. On the island of Belle Island in Conception Bay, near New Foundland, a powerful hematite deposit is known with an ore reserve of 3.5 billion tons. The ore represents is red iron ore with an admixture of chamoisite (see below); the average iron content is about 52%, phosphorus - about 0.9%. In Brazil, near Itabira there are different types red iron ores (iron mica, clastic, conglomerates, etc.). In Spain, the Bilbao deposits in the province of Vizcaya are heavily developed. The ore contains iron from 50 to 58%. In Germany there are deposits of red iron ore in Hesse-Nassau, the Harz, and Saxony. There is a very powerful deposit of iron luster and red iron ore on the island of Elbe; the ore contains 60-66% Fe and 0.05% P 2 O 5. In Algeria there is a fairly significant deposit of iron luster Filfilah; Fe content 52-55%; a little manganese; there is very little sulfur and phosphorus.

II. Ores containing hydrous iron oxides . These ores include brown iron ore, or limonite, 2Fe 2 O 3 ·ZN 2 O in all its varieties. In nature, brown iron ore is usually mixed with clay, quartz, limestone and other minerals that contribute to the waste rock harmful impurities, are: sulfur pyrite, lead luster, zinc blende, vivianite, apatite, etc. As a matter of fact, the name limonite usually covers various mixtures of iron hydroxides that differ in water content, such as goethite Fe 2 O 3 H 2 O, xanthosiderite Fe 2 O 3 ·2H 2 O, turyite 2Fe 2 O 3 ·H 2 O and others. The color is brown, sometimes yellow, the streak is brownish-yellow. The following varieties of brown iron ore are known: 1) dense, or ordinary - cryptocrystalline dense composition; very common, found along with red iron ores; 2) brown glass head - radiant and shell-shaped; 3) bean ore, or oolitic brown iron ore, found in the form of large grains and concretions; 4) marsh, meadow and turf ores; found at the bottom of swamps under turf in the form of loose granular deposits mixed with clay, sometimes in the form of spongy masses; 5) lacustrine ores, found at the bottom of lakes in the form of accumulations of grains, cakes, plates mixed with sand; 6) needle-shaped and fibrous brown iron ore called goethite.

The main deposit of brown iron ore in the USSR is located in the Urals - the Bakalskoye deposit in the Zlatoust district (section - Fig. 3). The ore is recognized as the best of all so far known. Iron content up to 60%. Along with brown iron ore, spar iron ore is found in places. In addition, there is a variety called "pencil ore" with a manganese content of 2-3%. Mineralogically, this ore contains a lot of turyite, often enclosing goethite crystals. The total ore reserve is about 73,630,000 tons (data from the Geological Committee). To the south of the Bakal deposits there is also a vast territory (Komarovskaya, Zigazinskaya, Inzerskaya dachas), where numerous deposits of brown iron ores have been very little explored and only partly used (by the Beloretsk plants). These deposits are in most cases nested in nature, containing iron from 42 to 56%; The ores are quite suitable for smelting and are an excellent admixture to the magnetic iron ores of Mount Magnitnaya, since they sometimes have an extremely low alumina content. The approximate reserve is 15 million tons (according to K. Bogdanovich). Of the brown iron ores of the Middle Urals, one can point out the powerful deposits of the Alapaevsk region. These iron ores are much poorer than those from the South Ural (42-48% Fe in a dry state); waste rock clayey-siliceous; These ores are low in phosphorus, contain little manganese, but contain an undesirable element - chromium (from traces to 0.2%). The possible reserve of this deposit is determined at 265,000,000 tons (according to Mikheev). In the central part of Russia, many factories arose in the areas where ores are located - Maltsevsky, Lipetsk, Kulebaksky, Vyskunsky and others. Large deposits have recently been found along the Khopru River. In the Donetsk basin, the deposits have lost their importance, since the ores here are poorer and worse than those in Krivoy Rog.

Among the foreign deposits of brown iron ore, we can mention Bilbao, Murcia and Almeria (Spain). Here the ore contains a lot of manganese, iron contains up to 55%; similar deposits exist in the Pyrenees. In England - in Cumberland and Lancashire there are deposits of a mixed nature - red iron ores in some places turn into brown ones. In Algeria there are significant deposits of brown iron ore along with iron sheen. In America, the most famous are the ores of Alabama, the reserves of which are greatly depleted. Thick deposits exist on Cuba Island (eastern part), which yield very fine earthy and highly aluminous brown iron ore, known as “Mayari ore,” containing chromium and nickel. For analyzes of brown iron ores, see Table. 4.

Oolitic iron ore. In our Union, we have a huge deposit of oolitic brown iron ore on the Kerch Peninsula. The ore occurs in three layers; the upper and lower layers of ore (dark) contain less Fe and more Mn; the middle layer gives the best ore (light), contains more iron (40-43%), and Mn - from 0.5 to 1.3%. Waste rock of ore is siliceous-alumina; This causes the use of lime flux during melting. Due to its high hygroscopicity, this ore requires preliminary drying for pressing into briquettes. The ore is dusty, weakly cemented, and contains 20% pieces, which makes smelting difficult. A significant P content requires the addition of Krivoy Rog (low phosphorus) ore, which is also necessary to reduce the arsenic content. The reserve is determined at 900 million tons, and together with the ores of the Taman Peninsula up to 3000 million tons (according to K. Bogdanovich).

Of the foreign oolitic iron ores, a colossal deposit is known, lying almost entirely on French territory (after the war of 1914-18) and covering a large border strip of Germany, Luxembourg and partly Belgium. The so-called Minette ore from this deposit is smelted. Thomas cast iron. The iron content in it is 25-36%. In France, near Mazney (Seine-et-Loire department), oolitic iron ores containing vanadium are mined. In England, very poor (25-35%) brown iron ores occur in Cleveland, Yorkshire and other places.

Swamp, meadow and turf ores. In the USSR, swamp and meadow ores are rich Leningrad region, Karelian Autonomous Soviet Socialist Republic, Tver, Smolensk and Kostroma provinces, Volyn and Tambov districts; They are also found in the Urals. Abroad they are available in southern Sweden, northern Germany, Belgium, Holland, and Canada. These ores are small, friable, and very easily restored. Their iron content ranges from 25 to 35%, rarely more; Phosphorus is most often contained in the range from 0.2 to 2%. Occurrence - nesting; nests are scattered at large distances from each other.

Lake ores. These ores occur at the bottom of lakes in the form of a continuous crust or separate layers. The iron content in them varies from 30 to 40%; sometimes they are rich in manganese (8-10%). There are especially many of these ores in Karelia. With cheap charcoal, these ores will be of industrial importance for the region.

In table Table 5 shows analyzes of oolitic, lake, swamp and meadow ores.

III. Ores containing iron carbonate. Siderite, or spar iron ore, FeCO 3 crystallizes in a hexagonal system (rhombohedral). Hardness 3.5-4.5; specific gravity 3.7-3.9. It occurs in the form of veins and layers accompanied by sulfur, copper and arsenic pyrites, heavy spar, zinc blende, and lead sheen. In addition, it occurs in the form of granular and oolitic masses or kidney-shaped, spherical concretions and shell-like nuclei (spherosiderites). Siderite - gray with a bluish tint, sometimes brown. Iron content 25-40%.

Coal iron ore(blackband) is a spar iron ore permeated with carbonaceous matter. Iron content 25-30%. Color black-brown or black. Specific gravity 2.2-2.8.

In the USSR, good spar iron ores are found in significant quantities in the Bakal deposit, where they occur with brown iron ores.

Among the foreign ones, the most famous deposit is in Styria (Mount Erzberg). The thickness of the deposit reaches 125 m. The ores are clean. Iron content 40-45%. In Germany, the Siegen deposit is known, covering part of Westphalia, Rhine Prussia and Nassau. In France - in Allevard and Visely (Isère department) - the thickness of spar iron ore veins reaches 10 m; there is a similar deposit in Savoy. Deposits of spar iron ore are also found in Hungary and Spain. In the United States of America, spar iron ore deposits occur from Western Pennsylvania to Alabama.

In the USSR, nests and interlayers of spherosiderites (clayey siderites) are very common in the Moscow region coal basin; These include deposits near Lipetsk (section - Fig. 4), Dankov, Tula and other places. These ores are more or less phosphorous and not rich in iron (38-45%). In the Vyatka province, deposits in the region of the Kholunitsky and Omutninsky factories are known (the oldest iron foundries in the district are Klimkovsky, 1762, Zalazninsky, 1771). Ore-bearing layers and nests occur in Permian deposits, in the so-called. ore land. The ore is a clayey spar iron ore mixed with limonite in the upper parts of the deposit. In the central part of the RSFSR there are a huge number of nest-shaped deposits of low thickness, scattered over large area, which depreciates the industrial value of these ores, the reserves of which were calculated by K. Bogdanovich at a colossal figure of 789 million tons.

Czestochowa deposits of spherosiderites are known in Poland. In Cleveland there are thick deposits of clayey ironstones of oolitic composition with an iron content of 30-35%; About 6 million tons of them are mined annually. In Germany, spherosiderites are found in the river basin. Ruhr, in the area of ​​Essen and Bochum.

In table 6 shows analyzes of ores containing iron carbonate.

IV. Ores containing iron silicate . These include: 1) chamoisite 3(2FeO·SiO 2)·(6FeO·Al 2 O 3)·12H 2 O; its color is greenish-gray, its composition is fine-grained, its hardness is about 3, its specific gravity is 3-3.4; iron content up to 45%; deposit in France, in the valley of the river. Chamoisy; in addition, it is found in Bohemia; chamoisite as an impurity is included in the amount of 23% in the composition of red iron ore from one of the largest deposits of Belle Island; 2) knebelite - theoretical composition: (Mn, Fe) 2 SiO 4; color reddish or brownish-gray; its specific gravity is about 3.7; found in Sweden; It has no industrial significance as an ore.

V. Iron ore surrogates . By this name are meant compounds of factory or factory origin, rich in iron ore, from which iron can be profitably extracted. This group includes slags from processing industries, puddling slags and slags. Their total iron content usually ranges from 50 to 60%. Thomas slag is sometimes used in blast furnace smelting to enrich cast iron with phosphorus. Often the “cinders” or “burnings” of sulfur pyrites used to produce sulfuric acid are used in the smelting. In America, the remains of franklinite are melted down after the zinc is extracted from it. Analyzes of iron ore surrogates are given in Table. 7.

Iron ore is a special mineral formation that includes iron and its compounds. Ore is considered iron if it contains this element in sufficient quantities to make it economically viable to extract it.

The main variety of iron ore is It contains almost 70% iron oxide and ferrous oxide. This ore is black or steel gray in color. Magnetic iron ore in Russia is mined in the Urals. It is found in the depths of Vysokaya, Grace and Kachkanar. In Sweden, it is found in the vicinity of Falun, Dannemora and Gellivar. In the USA it is Pennsylvania, and in Norway it is Arendal and Persberg.

In ferrous metallurgy, iron ore products are divided into three types:

Separated iron ore(low iron);

Sinter ore (with medium iron content);

Pellets (raw iron-containing mass).

Morphological types

Iron ore deposits that contain more than 57% iron in their composition are considered rich. Low-grade ores include those containing at least 26% iron. Scientists have divided iron ore into two morphological type: linear and flat-like.

Linear type iron ore occurs as wedge-shaped ore bodies in zones of bends and faults in the earth. This type is characterized by a particularly high iron content (from 50 to 69%), but sulfur and phosphorus are contained in small quantities in such ore.

Flat-like deposits occur on top of layers of ferruginous quartzite, which represent the typical weathering crust.

Iron ore. Application and production

Rich iron ore is used to produce cast iron and is mainly used for smelting in converter and open-hearth production or directly for iron reduction. Small quantity used as a natural paint (ocher) and a weighting agent for clay

The volume of world reserves of explored deposits is 160 billion tons, and they contain about 80 billion tons of iron. Iron ore is found in Ukraine, and Russia and Brazil have the largest reserves of pure iron.

Global ore production volumes are growing every year. In most cases, iron ore is mined using the open-pit method, the essence of which is that all the necessary equipment delivered to the deposit, and a quarry is built there. The depth of the quarry is on average about 500 m, and its diameter depends on the characteristics of the deposit found. After this, using special equipment, iron ore is mined, placed on vehicles designed to transport heavy loads, and delivered from the quarry to factories that process it.

The disadvantage of the open method is the ability to mine ore only at shallow depths. If it lies much deeper, you have to build mines. First, a trunk is made that resembles a deep well with well-reinforced walls. IN different sides Corridors, the so-called drifts, extend from the trunk. The ore found in them is blasted, and then its pieces are raised to the surface using special equipment. Mining iron ore this way is effective, but involves serious dangers and costs.

There is another method by which iron ore is mined. It is called SHD or borehole hydraulic extraction. Ore is extracted from the ground in this way: they drill a well, lower pipes with a hydraulic monitor into it and crush the rock with a very powerful water jet, which is then raised to the surface. Mining iron ore using this method is safe, but, unfortunately, ineffective. This way, only 3% of the ore can be extracted, and 70% is mined using mines. However, the development of the SHD method is improving, and there is a high probability that in the future this option will become the main one, displacing mines and quarries.