Powder engine. Problems, innovations and new technologies in Russian non-ferrous metallurgy New technologies in metallurgy

The history of mankind has more than one thousand years. Throughout the entire period of the existence of our race, there has been a steady technological progress, an important role in which was played by the ability of a person to handle metal, create and mine it. Therefore, it is quite logical that metallurgy is something without which it is impossible to imagine our life, the normal performance of work duties, and much more.

Definition

First of all, it is worth understanding how scientifically, from a technical point of view, they call the modern sphere of production.

So, metallurgy is a branch of science, technology, which covers the process of obtaining various metals from ore or other materials, as well as all processes related to the transformation of the chemical composition, properties and structure of alloys.

Structure

Today, metallurgy is the most powerful industry. In addition, it is a broad concept that includes:

• Direct production of metals.
• Processing of metal products both hot and cold.
• Welding.
• Application of various metal coatings.
• Section of science - materials science. This direction in the theoretical study of physical and chemical processes focuses on the knowledge of the behavior of metals, alloys and intermetallic compounds.

Varieties

All over the world there are two main branches of metallurgy - ferrous and non-ferrous. Such a gradation has developed historically.

Ferrous metallurgy is the processing of iron and all alloys in which it is present. Also, this industry involves the extraction from the bowels of the earth and the subsequent enrichment of ores, steel and iron foundry production, rolling of billets, production of ferroalloys.

Non-ferrous metallurgy includes work with ore of any metal except iron. By the way, they are conditionally divided into two large groups:

Heavy (nickel, tin, lead, copper).

Lightweight (titanium, magnesium, aluminum).

Scientific Solutions

There is no doubt that metallurgy is an activity that requires the introduction of innovative technologies. In this regard, many countries of our planet are actively research work, the purpose of which is to study and apply in practice a wide variety of microorganisms that would help to solve, for example, such a topical issue as wastewater treatment, which is a mandatory component of metallurgical production. In addition, processes such as biological oxidation, precipitation, sorption, and others have already become a reality.

Separation by technological process

Metallurgy plants can be conditionally classified into two main groups:

Pyrometallurgy, where processes take place at very high temperatures (melting, roasting);

Hydrometallurgy, which consists in the extraction of metals from ores with the help of water and other aqueous solutions using chemical reagents.

The principle of choosing a site for the construction of a metallurgical plant

In order to understand on the basis of what conclusions a decision is made to build an enterprise in a particular place, it is worth considering the main factors for the location of metallurgy.

In particular, if the question concerns the location of a non-ferrous metallurgy plant, then criteria such as:

• Availability of energy resources. The production associated with the processing of light non-ferrous metals requires an enormous amount of electrical energy. That's why similar enterprises built as close as possible to hydroelectric power plants.
• Required amount of raw materials. Of course, the closer the ore deposits are, the better, respectively.
• environmental factor. Unfortunately, the countries of the post-Soviet space cannot be classified in the category where metallurgy enterprises are environmentally friendly.

Thus, the location of metallurgy is a most complicated issue, the solution of which should be given the closest attention, taking into account all kinds of requirements and nuances.

In order to form the most detailed picture in the description of metal processing, it is important to indicate the key areas of this production.

Ferrous metallurgy enterprises have several so-called redistributions in their composition. Among them: sintering, steelmaking, rolling. Let's consider each of them in more detail.

Domain production

It is at this stage that iron is released directly from the ore. This happens in a blast furnace and at temperatures above 1000 degrees Celsius. This is how iron is smelted. Its properties will directly depend on the course of the melting process. By regulating the smelting of the ore, one can ultimately obtain one of two conversion (used later for the production of steel) and foundry (iron blanks are cast from it).

Steel production

Combining iron with carbon and, if necessary, with various alloying elements, the result is steel. There are enough methods for its smelting. Let us especially note the oxygen-converter and electrosmelting, which are the most modern and highly productive.

Converter melting is characterized by its transience and the resulting steel with the required chemical composition. The process is based on blowing oxygen through the lance, as a result of which the pig iron is oxidized and transformed into steel.

The electric steelmaking method is the most efficient. It is thanks to the use of arc furnaces that the highest quality alloyed steel grades can be smelted. In such units, the heating of the metal loaded in them occurs very quickly, while it is possible to add the required amount of alloying elements. In addition, the steel obtained by this method has a low content non-metallic inclusions, sulfur and phosphorus.

alloying

This process consists in changing the composition of steel by introducing calculated concentrations of auxiliary elements into it for subsequent imparting certain properties to it. Among the most commonly used alloying components are: manganese, titanium, cobalt, tungsten, aluminum.

rental

Many metallurgical plants have a rolling group of workshops. They produce both semi-finished products and already completely finished products. The essence of the process is the passage of metal in the gap between the mill rotating in opposite directions. Moreover, the key point is that the distance between the rolls should be less than the thickness of the passed workpiece. Due to this, the metal is drawn into the lumen, moves, and eventually deforms to the specified parameters.

After each pass, the gap between the rolls is made smaller. Important point- often the metal is not ductile enough in a cold state. And therefore, for processing, it is preheated to the required temperature.

Consumption of secondary raw materials

AT modern conditions the market for the consumption of recycled materials, both ferrous and non-ferrous metals, is steadily developing. This is largely due to the fact that ore resources, unfortunately, are not renewable. Each year of their production significantly reduces reserves. Considering the fact that the demand for metal products in mechanical engineering, construction, aircraft building, shipbuilding and other sectors of the national economy is steadily growing, it seems quite reasonable to develop the processing of parts and products that have already exhausted their resource.

It is safe to say that the development of metallurgy is to some extent explained by the positive dynamics of the industry segment - the use of secondary raw materials. At the same time, both large and small companies are engaged in the processing of scrap metal.

World trends in the development of metallurgy

In recent years, there has been a clear increase in the output of rolled metal products, steel and cast iron. This is largely due to the real expansion of China, which has become one of the leading planetary players in the metallurgical production market.

At the same time, various factors of metallurgy allowed the Celestial Empire to win back almost 60% of the entire world market. The remaining ten major producers were: Japan (8%), India and the United States of America (6%), Russia and South Korea(5%), Germany (3%), Turkey, Taiwan, Brazil (2%).

If we consider 2015 separately, then there is a tendency to reduce the activity of metal product manufacturers. Moreover, the largest decline was noted in Ukraine, where the result was recorded, which is 29.8% lower than last year.

New technologies in metallurgy

Like any other industry, metallurgy is simply unthinkable without the development and implementation of innovative developments.

So, employees of the Nizhny Novgorod state university developed and began to put into practice new nanostructured wear-resistant hard alloys based on tungsten carbide. The main direction of application of innovation is the production of modern metalworking tools.

In addition, a grate drum with a special ball nozzle was modernized in Russia in order to create a new technology for processing liquid slag. This event was carried out on the basis of the state order of the Ministry of Education and Science. Such a step fully justified itself, since its results ultimately exceeded all expectations.

The largest metallurgy enterprises in the world

• ArcelorMittal is a company headquartered in Luxembourg. Its share is 10% of the total world steel production. In Russia, the company owns the Berezovskaya, Pervomaiskaya, Anzherskaya mines, as well as the Severstal Group.
• Hebei Iron & Steel- a giant from China. It is wholly owned by the state. In addition to production, the company is engaged in the extraction of raw materials, its transportation and research and development. The company's factories use exclusively new developments and the most modern technological lines, which allowed the Chinese to learn how to produce ultra-thin steel plates and ultra-thin cold-rolled sheets.
• Nippon Steel- representative of Japan. The management of the company, which began its work in 1957, is seeking to merge with another enterprise called Sumitomo Metal Industries. According to experts, such a merger will allow the Japanese to quickly reach the first place in the world, overtaking all their competitors.

Metallurgy today, like 30 years ago, is conditionally divided according to its purpose into two groups: the first works for mass production, the second is special metallurgy. Accordingly, the materials are divided into those for which there are no special requirements, except for the price. And those for which special characteristics are very important. One of the main tasks of special materials is not to be structural in the traditional sense, since their bearing capacity is not very important, but to be a part or basis for a resource product.

The functional characteristics of steel materials are largely based on the coatings that are applied to them. They give materials new properties - heat resistance and tribological qualities.

Another one important feature modern metallurgy is that it should serve as the basis for recycling, that is, it is necessary to take into account the entire life cycle materials. Today, more complex and expensive ore bases are used as raw materials than before. Therefore, it is necessary to involve in processing other sources of resources that have been recovered from non-traditional raw materials, primarily secondary ones. At the same time, the requirements for the quality of materials obtained from recycled materials remain very high.

One of the main trends in modern metallurgy is the struggle for the "purity" of the material - the removal of coarse contaminants and harmful impurities, the elimination of cracks during operation. The term "pure steel", which appeared in the late 1970s and early 1980s, disappeared for some time, and now appears again. But if earlier we talked about inclusion sizes of 20-40 microns, now it is no more than 2-3 microns, and more often there is a zero level of pollution. As a result, even traditional alloys become new in their service properties.

The classic modern metal material has two main characteristics. First, it is a structural material that is predictable both in its properties and in its cost, which can be controlled. Economic considerations, of course, indicate that the metal does not give up its positions.

There have been two subtle revolutions in metalworking technology over the past few years. One of them was based on the emergence of five-axis machines and carbide tools based on tungsten carbide. The second is related to the emergence of so-called additive technologies based on completely new principles for metallurgy. Five-coordinate machines have become familiar today. But additive technologies will show themselves in the next three to five years.

And this significantly changes the traditional metallurgy. It can be imagined that many high-quality products and high-quality materials can change their form of existence - they will mainly be produced in the form of a powder. And the parts will be made from them in fact by a direct method. Confirmation of the seriousness of such trends is the information published a few days ago that General Electric is going to invest $1.4 billion in the merger of well-known companies specializing in 3D printing: the Swedish Arcam AB and the German SLM Solutions Group AG. The stated goal of the association is to start producing products for engine building and energy based on 3D technologies. There is no doubt that this will greatly shake up the market and give an additional impetus to the development of these technologies.

Scientists develop materials that can work in extreme temperatures

Speaking of new materials, one cannot fail to mention polymers. Carbon fiber has long been known: the body of the Boeing 787 is made entirely of this material. In such products, where both good mechanical properties and lightness, of course, such materials will replace metals, especially if they are used in extreme conditions. But now the interpenetration of metal and polymer in structural materials is so strong that it is already difficult to say what it really is: in terms of thickness it is a polymer, in terms of properties it is a polymer on a metal.

Today the industry works in several directions. First, it is the development of materials that can work in extreme temperatures. Secondly, important work in progress over extending the life of materials that can stand for 100 years with a guarantee. This is true, for example, for nuclear power. Also, many companies and research teams are developing biocompatible materials, and especially composites, since we have already learned how to combine metals with non-metals and obtain new durable materials. They are required by modern medicine for the production of implantable devices, prosthetics, etc.

By the way

A material has been created that is not inferior in strength to metal, and at the same time is 100 times lighter than expanded polystyrene. The material, known as "microgrid", was developed by scientists from HRL Laboratories (USA), which is owned by Boeing and General Motors. It is 99.9 percent air and is organized into a grid of tiny hollow tubes. The thickness of their walls is only 100 nanometers - 1000 times thinner than a human hair. The video shown by the developers shows that a fragment of the microlattice lies on a pubescent dandelion without crushing it.

The microlattice was made from the well-known nickel-phosphorus metal, but with an unusual architecture and an innovative 3D-printed manufacturing process. This technology has great prospects in the aircraft industry, the creation of spacecraft and in other areas of production where ultralight, but very strong materials are required. The properties of the microgrid are based on the same principles that made it possible to create the Eiffel Tower - a structure 324 meters high, but at the same time incredibly light. And Eiffel and his engineers, as you know, applied in their masterpiece the knowledge of how human bones are arranged. Modern technologies made it possible to translate the same principles into a very small scale.

The open-hearth process, which for a long time held a monopoly in the field of steel production, gave way in the late 60s of the XX century to a more productive oxygen-converter process. Further struggle was already going on between the converter and the electric steelmaking process, which was gaining momentum.

The dynamics of the development of steel production processes

Growing demand for special types steels and the development of mini-mills (small rolling mills with electric furnaces) strengthened the position of this method of steel production. The development of the main steel production processes since the middle of the 20th century is shown in the diagram:

According to the results of 2008, the share of open-hearth production in the world was 2.2%. Open-hearth production is concentrated mainly in the CIS countries (23.4% of total production steel at the end of 2008). In connection with the closure of redundant and inefficient production facilities against the backdrop of the global financial crisis, the share of open-hearth production in 2009 decreased significantly. Yes, on Russian enterprises the closure of the open-hearth shops was announced by Cherepovets Iron and Steel Works (Severstal) and Nizhny Tagil Iron and Steel Works (Evraz). Thus, according to the results of 2010, the share of open-hearth production was already 14.3% in the CIS countries and 1.3% - in the world.

The ratio between BOF and EAF processes in the total volume of steel production will remain in the near future: on the one hand, the number of incomplete cycle enterprises (mini-mills) using electrometallurgy is growing, on the other hand, the world's leading steel producer China is increasing the production of BOF steel (the share of oxygen -converter steel in China according to the results of 2010 is 90.2%).

The main components of the metal charge for steelmaking processes

The components of the metal charge for the production of steel in general case are cast iron, ferrous scrap and metallized raw materials (Direct Reduction Iron - DRI).

Metal charge for the main steelmaking processes can vary over a fairly wide range and depends in most cases on the availability of resources and the price ratios between them. Thus, during periods of rising cost of iron ore raw materials and falling prices for ferrous scrap, plants increase the use of scrap by reducing pig iron, and vice versa.

A general idea of ​​the technological ranges of change in the steelmaking charge can be obtained from the following table:

Oxygen-converter Electrosteel-smelting Open-hearth (scrap-ore process) Open-hearth (scrap process)

	Oxygen-converter	Electric steel-smelting	Open-hearth (scrap-ore process)	Open-hearth (scrap process)
Process share in steelmaking (world)	6 9,8 %	29,0 %	1,2 %
Process share in steelmaking (CIS)	6 4 ,6 %	2 1,1 %	1 4 ,3 %
Typical charge, %:
- liquid iron	75-80	0-30	25-55
- ferrous scrap	20-25	30-100	25-75
- pig iron		0-5	5-15
- metallized raw materials		0-70
Maximum share of scrap in metal charge (technological limitation)	28%	100%	45%	75%
Scrap Substitutes	cast iron liquid*	cast iron liquid*	cast iron liquid*	pig iron
	pig iron*	pig iron*	pig iron*

Note:

* - limited use

The greatest variability of the metal charge is observed in electric steelmaking. The heat source in the ESP is the energy of the electric arc and there is no need for other coolants, which eliminates the need for heat from the charge components.

As mentioned above, the open-hearth process, due to its insignificant share in world production, does not play a significant role in the consumption of metal raw materials. Thus, in general view the scheme of classical steel production is as follows:

Advantages of the classic scheme:

• high degree of iron extraction;
• high specific productivity;
• high thermal efficiency;
• efficient energy consumption.

Disadvantages of the classical scheme:

• high initial capital costs in the construction of new production;
• the need for preliminary agglomeration of the charge;
• use of coke as the main energy carrier and reducing agent;
• limited resources of quality ferrous scrap.

New processes for obtaining iron

The main reasons for the emergence of new iron production processes stem from the shortcomings of the classical scheme: the desire to shorten the technological chain and reduce dependence on the use of coke, the main reducing agent and heat source in classical pattern steel production. As a result, the terms “direct iron production” and “coke-free metallurgy” are often used in the designation of new processes.

According to the type of intermediate product produced, new processes for producing iron are divided into solid-phase and liquid-phase. The share of the latter is extremely small (5-6% of all coke-free metallurgy) and their semi-finished product cannot be used as a full-fledged alternative to scrap as part of the metal charge.

The raw materials for the new processes are iron ore or iron ore pellets. Thus, the reduction stage (transfer of iron from an oxidized form to a metallic one) is also present in alternative metallurgy processes.

As a reducing agent in solid-phase processes, products of conversion (conversion into CO and H2) of natural gas or products of coal gasification are used. Due to the relatively low efficiency, the use of coal gasification is limited. Recently, the processes associated with coal gasification have been most actively developed in India.

In liquid-phase processes, coal is the main reducing agent and heat source.

The scheme of steel production from metallized semi-finished product is shown below:

The variety of ideas and implementation schemes has given rise to many names for the processes and products of coke-free metallurgy. We list the most used of them:

• DRI - Direct Reduced Iron
• SI, SPI - Sponge Iron
• HBI - Hot Briquette Iron
• HDRI – Hot Direct Reduced Iron
• CDRI – Cold Direct Reduced Iron
• MP - metallized intermediate
• DRI - direct reduced iron
• ZHPP - direct iron
• DRI - direct reduced iron
• GZh - sponge iron
• HBI - hot briquetted iron
• Most common:
• DRI - processes and products of "coke-free" metallurgy production
• SI, SPI (GZH) - a product of solid-phase processes
• HBI (HBI) - briquetted product of solid phase processes

In general, the scheme for the production of a metallized product is shown below:

Classification of new iron production processes

According to the type of reducing agent used, new processes are classified into the following groups:

I. Natural gas

• continuous mine installation (Midrex, Armco, Purofer, HYL-III);
• mine installation of periodic action - retort (HYL-I, HYL-II);
• fluid bed unit.

II. Natural gas + coal

• rotary tube furnace, shaft plant (ITmk3).

• one-stage (Romelt);
• multistage (Corex, Finex, Hismelt, DIOS).

Processes of groups I and II are characterized by a solid metallized product, processes of group III produce a liquid intermediate. As mentioned above, the prevalence of Group III processes is very limited (5...6%), therefore, further presentation will concern aspects of the production and use of solid metallized products.

Development of technologies for the production of metallized intermediate products

The development of direct reduction processes goes in parallel in two directions: on the one hand, the number of implemented projects according to Midrex technology using natural gas as a source of reducing agents, on the other hand, processes based on coal conversion are being developed. This technology is most popular in India, a state with significant reserves of iron ore and coal and one of the smallest specific volumes of steel consumption (51 kg/person), which makes it promising for the development of the metallurgical sector.

Development of direct iron reduction processes (% of total DRI production)

2005

2010

Features of the production of a solid metallized product

The technological scheme for the production of a metallized product imposes certain requirements and imposes some restrictions on the raw materials used:

The metallization process is carried out in units with countercurrent hard materials and gases.

The need for agglomeration of raw materials to improve the gas permeability of the charge.

Cause	Consequence
Recovery occurs in solid form without the formation of liquid smelting products and separation of waste rock in the form of slag.	Restriction on the content of waste rock in the source material. The production of DRI requires high quality lumpy iron ore with a minimum amount of gangue.
Restoration occurs in solid form, i.e. passes without removing impurities.	Restriction on the content of undesirable impurities in the source material. Natural raw materials should contain a minimum of impurities and undesirable elements.
Absence of large-sized baking powder in the metallization unit.	The need to ensure a normal gas-dynamic regime leads to the need to reduce the diameter of the units. The negative result of this is a decrease in the specific productivity of the units.
The product is porous freshly reduced iron in a reducing environment inside a metallization unit.	Conditions arise for welding of material particles inside the unit. To reduce the effect, it is necessary to reduce the temperature level of the process, which leads to a decrease in specific productivity.
The product is porous freshly reduced iron, which is in an oxidizing environment outside the metallization unit.	A high contact area with air oxygen in a small volume leads to pyrophoricity - the possibility of self-ignition. To reduce this negative effect, passivation is necessary: ​​treatment with neutral substances, storage and transportation in a neutral environment, briquetting.

Thus, the main disadvantages of the new iron production processes are:

• low specific productivity of units;
• the need to use a charge with a high iron content and a low content of gangue and impurity elements;
• high demand for energy carriers and oxygen;
• high requirements for storage and transportation conditions.

DRI producing countries

Conditions for the feasibility of building DRI production plants:

• relatively little need domestic market in steel;
• small resources of metal scrap and coking coal;
• significant resources of iron ore and natural gas.

Plants for off-domain iron production are built mainly in developing countries that meet the conditions listed above: India, Venezuela, Iran, Mexico, Saudi Arabia. The dynamics of DRI production by country is shown in the charts.

The cost of a greenfield project for the production of DRI in the amount of 2 million tons per year is estimated at $350...$500 million. The main parameters of the project are:

Metallized Raw Material Quality, New Metallized Product - HBI

Produced by DRI are distinguished by high quality characteristics:

It was noted above that sponge iron, due to its large surface area, is prone to pyrophoricity as a result of oxidation in open air. Even if spontaneous combustion does not occur, as a result of the oxidation of the active freshly reduced iron, the iron content decreases and the metallurgical value of the DRI is lost. The dynamics of change in the content of Fe in sponge iron stored in the open air is shown in the diagram.

To reduce pyrophoricity and improve the bulk and utilization characteristics of DRI, hot briquetting technology is used. As a result of briquetting, the physical (bulk weight), logistical (storage, transportation) and technological (ease of use in electric furnaces) characteristics of DRI are improved. Briquette characteristics:

Briquette size, mm
Bulk weight, t / m 3

Briquetting effects:

• increase in bulk weight by 1.3...1.8 times;
• increase in density by 1.4...1.6 times;
• decrease in chemical activity (pyrophoricity) by an order of magnitude;
• ease of use in chipboard (reduction of loading time, location on the border of slag-metal).

World production and transportation of metallized semi-finished product

The dynamics of DRI production since 1970 is shown in the diagram.

World production DR

Advantages and disadvantages of using DRI in EAF

The main consumer of DRI is electric steelmaking - the share of DRI in the metal charge can reach 70%. At the same time, DRI has certain advantages over other charge components:

• stability of the chemical composition;
• low content of undesirable impurities (sulphur, phosphorus);
• absence of accompanying elements (lead, copper);
• ease of storage, loading / unloading, transportation;
• high bulk density;
• the possibility of feeding into the electric furnace without stopping the melting process;
• overall raw material guarantees the safety of electrodes from mechanical damage.

But the use of DRI in electric furnaces has its drawbacks:

• increase in electricity consumption (every 10% DRI: +15 kWh/t of steel);
• increase in the specific consumption of electrodes (every 10% DRI: +0.2 kg/t of steel);
• yield reduction (every 10% DRI: -0.4% of production volume);
• increase in melting time and decrease in productivity (every 10% DRI: +2.5 minutes);
• an increase in the thermal load on the lining at the beginning of the process.

These features of the use of DRI as a component of the charge of electrometallurgical production are reflected in the cost of DRI.

Fair Price DRI

When replacing 30% of scrap with DRI with a similar cost, the unit cost of steel production increases by $8/t (see diagram).

To fulfill the condition of cost equality per 1 ton of smelted steel, the DRI price should be 7% less than the price of high-quality scrap.

This assessment is confirmed by actual data - historically, the price of DRI is lower than the price of scrap metal by an average of 5% (maximum deviation -13%):

It should be noted that DRI is only a direct alternative for high quality scrap of comparable quality and size. In the absence of a sufficient amount of high-quality scrap, the production of steel of comparable quality is possible only if metallized raw materials are involved.

General information. Ferrous and non-ferrous metals. Main metallurgical processes.

Metallurgy

General information about metals and alloys

Metals are crystalline substances, the characteristic properties of which are high strength, ductility, thermal and electrical conductivity, a special luster called metallic. The properties of metals are due to the presence in their crystal lattice of a large number of moving electrons. Metals make up about 75% of the elements of the periodic system of D. I. Mendeleev.
Usually metals are used not in pure form, but in the form of alloys.
Metal alloys are substances formed as a result of the solidification of liquid melts consisting of two or more components. The components that form an alloy include chemically individual substances or their stable compounds. Metal alloys consist either only of metals (for example, an alloy of copper and zinc - brass), or of metals with a small content of non-metals (iron-carbon alloys - cast iron and steel). By changing the components and the ratios between them, alloys with a wide variety of physical, mechanical or chemical properties are obtained. After solidification, solid solutions, chemical compounds, or mechanical mixtures can form in the composition of alloys.
Solid solutions arise as a result of penetration into the crystal lattice of the base metal (solvent) of atoms of another metal or non-metal (soluble component). According to the type of arrangement of atoms of the soluble component in the crystal lattice of the solvent, substitutional and interstitial solid solutions are distinguished.
A substitutional solid solution arises as a result of the replacement of a part of the atoms in the crystal lattice of the base metal by the atoms of the dissolved component. Examples of substitutional solid solutions are alloys of copper with nickel, iron with nickel, chromium, silicon, and manganese.

In an interstitial solid solution, the atoms of the dissolved component are located in the free gaps between the atoms of the base metal. Usually, an interstitial solid solution occurs in a system consisting of a metal and a non-metal, for example, in an iron-carbon alloy. When solid solutions of metals are formed, strength, hardness, and electrical resistance increase, but ductility decreases in comparison with the base metal. Solid solutions form the basis of technical alloys: structural, stainless and acid-resistant steels, brass, bronze.
Chemical compounds are formed at a strictly defined quantitative ratio of components. Chemical compounds include, for example, iron carbide (cementite), which is part of iron-carbon alloys:
3Fe + C = Fe3C.
Cementite is characterized by high strength and hardness, but is very brittle. Chemical compounds of metal with metal are called intermetallic. This includes, for example, compounds of aluminum with copper CuA12, magnesium with zinc MgZn2, etc. Intermetallic compounds most often do not obey the normal valency rule. Presence chemical compounds strengthens alloys, but at the same time reduces their ductility.
Mechanical mixtures arise as a result of the intergrowth of crystals of the components that simultaneously precipitate from the liquid melt when it is cooled. In the crystals that are part of the mechanical mixture, the crystal lattice of the initial components of the alloy is preserved. Thus, each of the components retains its specific properties. Mechanical mixtures may consist of pure components, solid solutions, or chemical compounds.
All metals and alloys are divided into ferrous and non-ferrous.

Ferrous and non-ferrous metals

Cast iron contains carbon from 2 to 4.3%, in special cast irons (ferroalloys) the amount of carbon can reach 5% or more.
Cast iron is smelted in blast furnaces from iron ores. Iron ores are a natural mixture of iron oxides and a mineral part called waste rock (silica, alumina). In the process of ore smelting, iron is reduced from oxides, freed from harmful impurities and separated from waste rock.
Cast iron obtained during blast-furnace smelting, depending on the composition and purpose, are divided into gray, white and malleable.
Gray, or foundry, iron is obtained as a result of the slow cooling of liquid iron with a significant content of carbon and silicon in the ore. This type of cast iron has 1.7 to 4.2% carbon and up to 4.25% silicon. Gray cast iron fills molds well and is easily machined with cutting tools. After remelting cast iron in a furnace, it is suitable for pouring into pre-prepared molds.
In gray cast iron, carbon is in a free state in the form of graphite flakes. This structure of cast iron gives it a gray color in places of fracture.
White, or pig iron, contains up to 4.5% carbon. Depending on the method of obtaining, the following additives are introduced into cast iron; silicon, manganese, phosphorus, sulfur. This type of cast iron is obtained by rapidly cooling liquid cast iron. Carbon is found in white cast iron in a bound state in the form of cementite. In places of fracture, cast iron has a white color. White cast iron is hard and brittle; it is mainly used as a raw material for steel production.
Ductile iron contains 2 to 2.2% carbon. It is made from white cast iron. Castings are placed in steel boxes with clean sand and simmered in furnaces, that is, they are subjected to prolonged heating, and then slowly cooled.
Steel (GOST 5157-53) contains up to 2% carbon. Steel has high mechanical properties and technological properties.
Steel is made from cast iron different ways. Regardless of the method, the essence of the steelmaking process lies in the oxidation of undesirable impurities contained in cast iron, and the reduction in the content of carbon, silicon, manganese, phosphorus, and sulfur in it.
The Bessemer converter method for producing steel from cast iron is carried out in a converter.

In the converter, compressed atmospheric air is blown through the thickness of the cast iron at a pressure of up to 2.5 kgf/cm2, as a result of which the carbon is burned out and the cast iron is converted into steel. The heat released in this process raises the temperature of the metal to 1600°C. Recently, at many metallurgical plants oxygen-enriched air or pure oxygen is blown through iron in converters. This improves the quality of the smelted steel.
The open-hearth process for producing steel from cast iron is as follows. Solid or molten pig iron with the addition of scrap1 or ore is smelted on the hearth of an open-hearth furnace. The required temperature is created by burning a heated mixture of gaseous fuel and air.
The purpose of the open-hearth process is to remove (burn out) from the molten metal those elements that should not be in the finished steel and which enter the molten metal from the charge or from the gaseous medium, and also to reduce the content of those elements to the required norm. elements that are a necessary part of the steel. If necessary, the process is completed by introducing alloying elements into the steel.
Open-hearth steel is higher in quality than BOF steel, but the BOF method is more productive.

The electrosmelting method for producing steel is the most advanced in comparison with the methods described above. According to the essence of the ongoing processes, the electrosmelting method does not differ from the open-hearth method. But electric smelting makes it possible to obtain high-quality steels and simplify technological process smelting. The widespread use of this method is still limited by the high cost of electricity.
By chemical composition steels are divided into carbon and alloyed; both of these types of steels are used in construction. Carbon steels include: machine-building (structural) with a manganese content of up to 1.1% with a carbon content of up to 0.75%, tool steel with a low manganese content (up to 0.4%) with a carbon content above 0.6%. Alloy steels are low-alloyed with an alloy content of not more than 2.5%, medium-alloyed with a total content of alloying elements from 2.5 to 5.5%, high-alloyed with a total content of alloying elements of more than 5.5%.
Depending on the purpose, steel has four classes: construction steel is used in the form of rolled products without heat treatment for structures of bridges, buildings, wagons, etc.; machine-building - used for the manufacture of machine parts; instrumental - for the manufacture of various metal-cutting and other tools; special purpose - stainless acid-resistant, heat-resistant, scale-resistant, etc.

Ferrous metals include iron and iron-based alloys - steel and cast iron. Ferrous metals account for about 95% of the metal products produced in the world. In order to impart specific properties to ferrous metals, improving or alloying additives (nickel, chromium, copper, etc.) are introduced into their composition. Ferrous metals, depending on the carbon content, are divided into steels and cast irons.

Steel is a malleable iron-carbon alloy with a carbon content of up to 2%. It is one of the main structural building materials. Building structures, pipelines, reinforcement for reinforced concrete are made from steel.
According to the method of obtaining, the hoists are divided into open-hearth, converter and electric steels. According to the chemical composition, depending on the chemical elements included in the alloy, steels are carbon and alloyed.
Carbon steel along with iron and carbon, it contains up to 1% manganese, up to 0.4% silicon, as well as impurities of sulfur and phosphorus. If the amount of impurities does not exceed a given upper limit, they are called normal.
Cast iron is an iron-carbon alloy with a carbon content of 2 ... 4.3%. It also contains manganese, sulfur, silicon phosphorus. Most of the pig iron is used to make steel. In addition, it is used as an independent structural material. Depending on the form of carbon bonding, white and gray cast iron are distinguished.
White cast iron contains carbon in a chemically bound state in the form of iron carbide Fe3C.
In gray cast iron, carbon is in a free state in the form of graphite.

Ferrous metallurgy

A branch of heavy industry, which includes a complex of interrelated sub-sectors: metallurgical proper (blast furnace, steelmaking, rolling), pipe and hardware production, mining, enrichment and agglomeration of ore raw materials, coke production, production of ferroalloys and refractories, mining of non-metallic raw materials for ferrous metallurgy and secondary processing of ferrous metals. The most important types of ferrous metallurgy products are hot-rolled and cold-rolled steel, steel pipes and metal products.
Ferrous metallurgy is the basis for the development of most branches of the national economy. Despite the rapid growth in production chemical industry, non-ferrous metallurgy, building materials industry, ferrous metals remain the main structural material in engineering and construction. Thus, the share of ferrous metals in the total volume of structural materials consumed by the leading branches of engineering in the USSR exceeded 96% in 1976. The industry consumes approximately 20% of the country's fuel and energy resources.
For millennia, the development of human society has been inextricably linked with the use of iron as the main material for the manufacture of tools. V. I. Lenin called iron one of the foundations of civilization, one of the main products of modern industry.

Iron production in Russia has been known since ancient times. Iron ores were first smelted in raw-blast furnaces, then (from about the 9th century) in special ground-based blast furnaces blown with hand bellows. Factory production of pig iron and iron began in 1632–37, when the first plant with a blast furnace was built near Tula, smelting up to 120 poods of pig iron per day. In 1700 about 150,000 poods of cast iron were smelted. Increasing in the first quarter of the 18th century. its smelting by 5 times, Russia took first place in the world in the production of ferrous metals, and until the beginning of the 19th century. held him. However, in subsequent years, the growth rate of iron and steel declined, and by 1913 the country occupied only the fifth place in the world, and its share in the world production of iron and steel was 5.3%.

Technology of industrial steel production

Iron is one of the most abundant elements in nature. It contains about 5% in the earth's crust. However, it is not found in its pure form, as it easily combines with oxygen, forming oxides. The most famous iron ores from which iron is obtained are magnetite FeeCU (containing more than 70% iron), hematite Fe3C> 3 (30-50%), limonite FeO (OH), etc. Along with pure iron, the ore contains carbon, others metals, as well as harmful impurities - sulfur, phosphorus, nitrogen, etc.
The primary product obtained from the ore is cast iron (an alloy of iron and carbon). Cast iron is produced in blast furnaces by melting iron ore at T=1600°C with the addition of coke and limestone; In the process of burning coke, iron is reduced, while limestone is designed to more easily separate non-metallic impurities along with slag. Molten iron, as the heavier component, is collected at the bottom of the furnace and then discharged outside into special moulds. The resulting coarse-grained gray cast iron with 4% carbon content is used for casting, fine-grained white cast iron for steel production.
Steel is an alloy of iron with carbon, the percentage of which, due to special processing (alloying), is reduced to an amount not exceeding 1.2%. In modern metallurgy, three methods are used to produce steel from cast iron: open-hearth, bessemer and thomasovsky. The main raw materials for producing steel are white cast iron, scrap metal and waste (steel scrap), as well as additives in the form of silicon, manganese, chromium, nickel, copper, etc. to obtain steel grades with predetermined properties.
The most common method of obtaining building steels is open-hearth.

This method consists in the fact that on molten cast iron, placed in a special furnace lined with refractories, continuous flow air is supplied with hot gas, maintaining t = 2000 ° С. Under the influence of such a temperature, carbon is burned from the molten mass within 4–12 hours (depending on the required quality of steel), the percentage of which is strictly controlled.

The oxygen-converter method for producing steel, which has recently become increasingly widespread in world practice, consists in blowing a hot mixture of air with oxygen under pressure through molten cast iron. As a result, carbon and harmful impurities burn out in molten iron. Depending on the composition of the inner refractory lining of the converter, the method is called Bessemer (acid lining) or Thomas (main lining). The Thomas method of steel smelting does not guarantee the required quality, therefore this steel is not used for building structures in the country.
The highest quality multi-alloyed steels are obtained in special electric furnaces. The maximum temperature of about 2200 °C is achieved with the help of an electric arc that occurs between two carbon electrodes. The advantage of the method is that harmful elements from air and gas do not get on the molten metal, as is the case in the first two methods. Steel obtained by any method is cast into special molds and sent in this form for further processing in the production of rolled products, castings and other products.

Nonferrous metals. Non-ferrous metals include all metals except iron. Most often, metals and alloys based on aluminum, copper, zinc and titanium are used in construction.
Metals are very technologically advanced: firstly, products from them can be obtained by various industrial methods (rolling, drawing, stamping, etc.), and secondly, metal products and structures are easily connected to each other using bolts, rivets and welding.
However, from the builder's point of view, metals also have disadvantages. The high thermal conductivity of metals requires thermal insulation of metal structures of buildings. Although metals are non-combustible, the metal structures of buildings must be specially protected from fire. This is explained by the fact that when heated, the strength of metals decreases sharply and metal structures lose their stability and deform. Big damage national economy causes corrosion of metals. Finally, metals are widely used in other industries, so their use in construction must be economically justified.

Metallurgy (from the Greek "metallon" - "mine", "metal" and "ergon" - "work") - in the original, narrow meaning "the art of smelting metals from ores." In the modern sense, this is a field of science and technology and an industry that covers all processes for obtaining metals and alloys and giving them certain forms and properties.

Historically, there has been a division of metallurgy into non-ferrous and ferrous. Ferrous metallurgy includes iron-based alloys - cast iron, steel, ferroalloys (ferrous metals account for about 95% of all metal products produced in the world). Non-ferrous metallurgy includes the production of most other metals. In addition, metallurgical processes are also used to obtain non-metals and semiconductors (silicon, germanium, selenium, tellurium, etc.). But in general, modern metallurgy covers the processes of obtaining almost all elements of the periodic system, with the exception of halides and gases.
The science of metals is rapidly developing - metal science, the foundations of which were laid by the Russian scientists P. P. Anosov and D. K. Chernov. Metal scientists learn the structure of metals, find ways to improve their properties, create new alloys that allow designers to develop fundamentally new machines - extra light, extra strong, etc.

The basis of modern ferrous metallurgy is made up of factories, each of which is equal to a small city in terms of territory and number of employees. Metal passes through a difficult path here. First, ore is enriched at mining and processing plants (GOK), then it is burned at ferrous metallurgy plants, turning it into sinter or pellets. Of these, iron is smelted in blast furnaces. Then the pig iron enters the steel shop, where it is melted into steel in open-hearth furnaces, oxygen converters or electric furnaces (see Electrometallurgy). Steel ingots are transported to rolling shops, where metal products are made from them: rails, beams, sheets, pipes, wire (see Rolling, rolling mill). Rails are laid between the workshops, along which trains run, delivering ore and liquid iron, steel ingots and finished rolled products.
The same, and in a number of cases even more complex, path is followed by metals at non-ferrous metallurgy plants. The technological process for obtaining some non-ferrous metals includes dozens of operations.
What is the future of metallurgy? Is it really necessary for humanity to constantly build gigantic factories in order to satisfy its needs for metal? After all, we should not forget that metallurgy mainly deals with fire: in order to melt ore or steel, they must be heated to a high temperature. And pyrometallurgy (this is the name of the branch of metallurgy that uses metal heating: from the Greek word “feast” - “fire”) burns oxygen in the air, clogs the atmosphere with combustion waste, spends a lot of fresh water on cooling units. In short, it harms nature. Therefore, scientists have developed new ways of developing metallurgy. This is, first of all, the direct reduction of iron from ore, bypassing the blast-furnace process. Direct reduction plants, which are fully automated and securely sealed, will smelt ore into metal ingots or pure iron powder. And then the ingots or powder, packed in containers, will be delivered to machine-building plants, where products will be made from them either by the usual method or by powder metallurgy. These factories do not have to be as huge as the existing ones. On the contrary, they will be small and, as scientists suggest, sometimes mobile, that is, mobile. On barges or with the help of helicopters, they will be delivered to small ore deposits, the development of which is now considered unprofitable. Mini-plants, fully automated, will make the development of these deposits economically viable.
Electrometallurgy is developing rapidly, and electricity is increasingly being used at all subsequent stages of metal processing. Next in line is the creation of a fully automated metallurgical production, controlled by a computer - metallurgical workshops-automatic machines.

Corrosion of metals

The processes of destruction of materials caused by the action of various chemicals on them are called corrosion. chemicals that destroy Construction Materials are called aggressive. An aggressive medium can be atmospheric air, water, various solutions of chemicals, gases.
Atmospheric corrosion occurs under normal atmospheric conditions when air oxygen, moisture and metal interact. This corrosion affects products that have a large surface, such as roofs, metal trusses, rafters, bridges.
Underwater corrosion is exposed to various structures in the water, and the process is enhanced in the presence of even a small amount of acids or salts in the water.
Soil corrosion occurs when soil acts on the metal of water and sewer networks. Corrosion is enhanced by the presence of salts in soil water and fluctuations in groundwater levels.
Depending on the nature of the aggressive environment, metal corrosion can occur by chemical and electrochemical means.
The chemical corrosion process occurs when metals are exposed to dry gases at high temperatures or liquid non-electrolytes (liquids that do not conduct electric current). To chemical corrosion the destruction of metal by oxygen in dry air and other gases (carbon dioxide, sulfur dioxide) also applies.
The electrochemical corrosion process is caused by the action of electrolytes on the metal - liquids that carry an electric current. In electrochemical corrosion, the destruction of the metal is associated with the occurrence and flow of electric current from one part of the metal to another. Under the action of acid and alkali solutions on the metal, the metal gives up its ions to the electrolyte, and itself is gradually destroyed. An electrochemical corrosion process can also occur when two dissimilar metals come into contact. For example, upon contact of iron with chromium, chromium will be destroyed, iron with copper will destroy iron.

In some cases, the corrosion process is caused by stray currents spreading in the soil from the rails of electrified railways and passing through the earth, as well as through various metal devices laid in the ground (electric cables, water pipes). Stray currents, hitting metal pipelines and other underground devices located in moist and salty soil, create conditions for electrolysis. Ions (electrically charged metal particles) pass into the soil solution (electrolyte); as a result of the loss of elementary metal particles, corrosion ulcers appear on underground cables, water and sewer pipes.
The corrosion process can be local, when the destruction of the metal occurs in some areas, uniform, when the metal is equally destroyed over the entire surface, and intergranular, when the destruction occurs along the grain boundaries of the metal. A clean unprotected metal surface in most cases is subject to corrosion processes. various kinds. The oxide film formed at the same time on the surface of some metals can stop the development of the corrosion process. Such protective films appear on the surface of copper, bronze, aluminum. Steel belongs to the metals that resist the corrosion process poorly; destruction of the surface of steel products caused by the corrosion process quickly spreads to the inner layers of the metal,
Losses from corrosion processes bring great material damage to the national economy. This phenomenon can be combated by various means.
Where possible, metals are replaced with other materials that are less susceptible to corrosion. E-if metal structures cannot be replaced, they are covered with varnishes, enamels. The resulting film protects the metal from the action external environment. To protect against corrosion, metal structures are coated with paints, galvanized, tinned, chrome-plated. In addition, for the manufacture of structures, metals are used that are most resistant to this aggressive environment. For example, low-alloy steels are used in conditions of low humidity and exposure to alkalis, high-alloyed steels are used in conditions of high humidity and highly aggressive gases. Alloying with nickel sharply increases the resistance of steel to atmospheric and underwater corrosion.
Metal building structures are protected from corrosion processes by flame spraying on their surface of powdered plastic polymers, including polyethylene, polypropylene, nylon, as well as special compositions of these materials with or without the addition of powdered fillers and dyes.

The global crisis had a negative impact on the Russian economy, but the metallurgical industry has retained its capabilities thanks to previous large cash contributions. Metallurgy is the main branch of state industry, a kind of foundation for the development of the economy as a whole.

In the country's total exports, the share of metallurgy is 14%. More than 40% of the steel smelted in the Russian Federation is exported. The production of metallurgists in GDP is 5%, in all industrial complex- 17%. The metallurgical industry makes a significant contribution to the country's economy and fills the budget. In connection with the unfavorable economic situation, a plan was also adopted to replace imported products with domestic ones. Increasing the competitiveness of the industry is included in the strategic plans state level. Industry enterprises are modernizing and applying.

Demanded innovations relate to updating technologies, reducing resource intensity, and improving the environmental component in metallurgy. Particular emphasis is placed on electrode, carbon-graphite, hard-alloy, semiconductor, rolling products. To avoid the decline in the steel industry, it is necessary to intensify innovative activity. Research institutions provide significant assistance in the modernization of the industry.

10 innovations in metallurgy 2018

Innovations in metallurgy:

1. Carousel oven. Involved in ferrous metallurgy, reduces stress in the hearth of the furnace.
2. Designed and put into operation Vanyukov furnace for processing slag and waste in non-ferrous metallurgy. An analogue of this innovation is the Romelt furnace, which is used in ferrous metallurgy. Its advantage is the ability to work on low-grade coal and the processing of slag waste. Although the efficiency of such a furnace is lower than that of a blast furnace, the latter is not capable of processing waste and slag. This is a big leap forward, because metallurgical plants are littered with waste that has nowhere to go. The cost of the project is about 250 million rubles, and construction outside the metallurgical plant will cost a billion rubles. The innovation was carried out through private investment.
3. The Chelyabinsk Zinc Plant is mastering the flotation technology for obtaining silver from zinc cakes. innovative technology gives up to 98 kg of silver from 100 kg of sulfide flotation concentrate.
4. A membrane technology for purification of complex solutions in metallurgy has been created. The innovation makes it possible to purify solutions from sulfates of heavy non-ferrous metals by 99%. The innovation opens up the possibility of creating a looped water circulation at the plants of the industry.
5. When melting iron and steel, a synthetic low-melting flux is used. The innovation helps to increase the ability of slags to be refined.
6. Dynamic nanotester. With the help of the invention, the physical and mechanical parameters of materials of different origin are investigated, the friction coefficient, modulus
   Young, nanohardness, etc.
7. Complex for research and diagnostics of bulk nanosubstances (nanotubes, powders for sintering and catalysis, medications). The innovation is designed to quickly determine the properties and characteristics of the material on different stages production.
8. Innovations also relate to the water supply of ferrous metallurgy. For calculating salt concentrations in subsections, optimizing the structure of water supply systems
   a technological model with its mathematical description has been developed.
9. The Elsit HDTV induction melting plant saves energy. Due to its high power, the oven heats up instantly and allows you to immediately
   melt metal.
10. Flat rolling equipment for cross-wedge rolling of workpieces is used in the manufacture of high-precision parts of complex configuration. The automated complex allows to increase productivity by 2 times, reduce the consumption of rolled metal by 30%, improve manufacturing accuracy and reduce the complexity of further operations.

The development of the metallurgical industry naturally enters into strategic planning federal level. The use of innovations in metallurgy, the introduction of modern technology, the modernization of the existing one increase the coefficient of renewal of the main production assets up to 5%. In the future, by 2020 the metallurgical industry will reach the world level in terms of the number of products produced.

Ferrous metallurgy

Innovations in ferrous metallurgy are involved in certain areas of production:

1. Domain.
   It is envisaged to build installations for blowing coal dust, increase iron smelting up to 20% and reduce natural gas consumption.
2. Steelmaking.
   Refusal to use open-hearth furnaces for steel production, reduction in the consumption of rolled metal to 1088 kg/t in 2020 from the current 1142
   kg/t. Use of heavy duty furnaces to save energy (350 kWh/t compared to the current 500 kWh/t).
3. Rolling.
   Increasing the output of sheet metal in the total output of metal up to 65%, bringing it to the level of economically developed countries.
4. Non-ferrous metallurgy
   The growth rate of the industry is caused by the need to replace imports with domestic products. Rapid growth requires innovative approach to technology, technique and organization of production. The instability of the external market and the insufficient capacity of the domestic market require the development of the latter.

The main issues of non-ferrous metallurgy are: an increase in the share of aluminum production in electrolyzers and an increase in capacities in the production of heavy non-ferrous metals using the technology of autogenous processes. By the deadline of the "Strategy for the development of ferrous and non-ferrous metallurgy in Russia for 2014-2020", their part should amount to 97% of the total production.

Combine "Severonickel"

An enterprise with a long history, since 1998 the Severonickel plant has been part of the Kola GCF JSC. Now matte is being processed on it and the production cycle is being completed.

Norilsk Nickel invested more than 20 billion rubles in the renewal of the nickel production at the Kola MMC. It is planned to master new technology electroextraction for nickel refining. Nickel anodes will not melt, as the raw material will be nickel powder. Gradually, the old electrolysis baths will be replaced with new ones. In total, it is planned to gradually replace 476 baths in the electrolysis shop.

The Kola Mining and Metallurgical Company is modernizing its processing plant. Improvements relate to automated process control systems. The complex is being replaced by a new one, since the production of spare parts has been discontinued and emergency situations are possible. New equipment is installed in stages. The slurry pumping station has already been replaced, 3 flotation sections are being modernized. In 2018, the entire hardware complex of the enterprise will be replaced.

The company plans to modernize the entire management system by the beginning of 2019 and combine it into one centralized system management of the enrichment plant SU of individual production sites. This will further improve the technological process, show flexibility when changing technological cycles.

The Severonickel plant is developing a new method for processing platinum-rhenium catalysts, which results in platinum concentrate and ammonium perrhenate.

A technological line for wastewater treatment to an acceptable level is being developed for the enterprise.

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