Technologies for the production of iron. Experiments to smelt iron from swamp ore

The production of iron in Rus' has been known since time immemorial. As a result of archaeological excavations in the areas adjacent to Novgorod, Vladimir, Yaroslavl, Pskov, Smolensk, Ryazan, Murom, Tula, Kiev, Vyshgorod, Pereyaslavl, Vzhishch, as well as in the area of ​​Lake Ladoga and in other places, hundreds of places with the remains of melting pots were found , raw furnaces, the so-called "wolf pits" and the corresponding tools for the production of ancient metallurgy. In one of the wolf pits, dug out for iron smelting, near the village of Podmokly in the southern part of the Moscow coal basin, a coin was found dated 189 of the Muslim era, which corresponds to the beginning of the 9th century of modern chronology. This means that in Rus' they knew how to smelt iron back in those distant, deeply pre-Christian times.

The names of the Russian people literally scream to us about the prevalence of metallurgy throughout the territory of ancient Rus': Kuznetsov, Kovalev, Koval, Kovalenko, Kovalchuk. In terms of prevalence, Russian "metallurgical" surnames, perhaps, compete even with the archetypal English John Smith (who, in fact blacksmith, that is, the same blacksmith).

However, the path of any sword or cannon barrel always began much earlier. metallurgical furnace and, especially, forges. Any metal is primarily a fuel (coal or coke for its smelting), and secondarily a raw material for its production.

Here I must immediately place emphasis. Why is fuel the first priority, while iron ore itself is so boldly relegated by me to the background? It's all about the logistics of transporting the ore and fuel needed to produce iron in the Middle Ages.

After all, the main, and the most high-quality fuel for the smelting of medieval, bloomery iron, was charcoal.
Even now, in the modern enlightened age, the task of obtaining high-quality charcoal is by no means as simple as it seems at first glance.
The highest quality charcoal is obtained only from a very limited number of wood species - from all fairly rare and slowly growing hardwood species (oak, hornbeam, beech) and from the archetypal Russian birch.
Already from conifers - pine or spruce, charcoal turns out to be much more fragile and with a large yield of fines and coal dust, and trying to get good charcoal from soft-leaved aspen or alder is almost unrealistic - the yield of a good one falls compared to oak almost twice.

In the event that there were not enough forests in the territory where iron deposits were found, or the forests in the area were destroyed by previous generations of metallurgists, various ersatz substitutes had to be invented.
For example, in Central Asia, despite high-quality iron ore deposits, it was tight with the forest, which is why instead of charcoal it was necessary to use the following innovative fuel:

If someone does not understand - this is cow dung. You can horse, mutton, goat or donkey - it does not play a special role. Kizyak was kneaded with hands into flat cakes (something like this), and then laid out to dry in the sun.
Of course, in such a situation, it was not necessary to talk about the "constancy of the composition" of the fuel, and the temperature of the flame from the combustion of such a "composite fuel" was much lower than that of high-quality charcoal.

Another, much more technologically advanced replacement for charcoal appeared in the world much later. It is, of course, about coke on which all modern ferrous metallurgy is now based.
The history of the "invention" of coke is only two hundred years old. After all, it was the coke oven battery in which "coal burned itself out" that was the first, most powerful volley of the industrial revolution. It is she, the coke oven battery, and not oil derrick created that "world of coal and steam" that we now love to remember in books, films and anime about steampunk.

Long before the Industrial Revolution, England was already exploiting rich deposits hard coal, which, however, was used almost exclusively for home heating. The smelting of ore in England was carried out, as in many places in the world, only on charcoal. This was due to an unpleasant fact, characteristic of most coals - they contain in their composition considerable amounts of phosphorus and sulfur, which are very harmful to the iron obtained in the furnace.

However, Great Britain is an island. And, ultimately, the growing needs of English metallurgy, based on charcoal, surpassed all the possibilities of English forests. English Robin Hoods had nowhere to hide- an increase in iron smelting has brought to naught almost all the forests of foggy Albion. This eventually became a brake on iron production, as smelting required a huge amount of wood: for the processing of one ton of ore - almost 40 cubic meters of wood raw materials.
In connection with the increasing production of iron, there was a threat of complete destruction of forests. The country was forced to import metal from abroad, mainly from Russia and Sweden. Attempts to use fossil coal for iron smelting were unsuccessful for a long time, for the reason indicated above.
It was not until 1735 that the breeder Abraham Derby, after many years of experience, found a way to smelt iron using coking coal. It was a victory. But before this victory at the beginning of the 9th century AD, there were still more than 900 years.

So, carry firewood (or even ready-made charcoal) to iron does not work simply because of the logistics of the process - fuel is needed by mass 4-5 times more than the mass of ore, and even more by volume - at least ten times. It is easier to bring iron to fuel.

Fuel in Ancient Rus' is, and in abundance. And what about the Russian platform with iron?
But with iron there are questions.
quality iron ore not on the Russian Plain.

I immediately catch screams: “What about the Kursk magnetic anomaly? The highest quality magnetic iron ore in the world!
Yes, one of the highest quality in the world. Opened in 1931. The depth of occurrence is from 200 to 600 meters. The task is clearly not for the technologies that were at the disposal of the ancient Slavs in the 9th century AD. It all looks beautiful now, but for that time the picture of a modern iron ore quarry is like a trip to Alpha Centauri for modern humanity. In theory it's possible, but in practice it's not.

As a result, in the 9th century in Rus', it is necessary to make a choice from something included in this list of all the iron ores currently used by mankind:

Magnetic iron ore - more than 70% Fe in the form magnetite Fe3O4 (example: the Kursk magnetic anomaly just described by us)
- red iron ore - 55-60% Fe in the form hematite Fe2O3 (example: again the Kursk magnetic anomaly or the Krivoy Rog basin)
- brown iron ore (limonite) - 35-55% Fe in the form mixtures of hydroxides ferric iron Fe2O3-3H2O and Fe2O3-H2O (example: ruined by Ukraine Kerch deposit).
- spar iron ore - up to 40% Fe in the form carbonate FeCO3 (example: Bakal deposit)

Magnetite and hematite lie deep on the Russian platform; there is no feldspar iron ore on it at all.
Remains brown iron ore (limonite).
The raw material, to put it mildly, is worthless - just look at the concentration of iron in it, but the joke is that it is on the territory of the then Rus' almost everywhere. In addition, this "almost everywhere" miraculously turns out to be in close proximity to the then source of high-quality coal fuel - the mighty forests of the Russian Plain.

This, of course, is about peat bogs and limonite, which is often called swamp iron.
In addition to marsh iron, a similar genesis has meadow and lake iron. However, as you will see later, it was most profitable to dig such iron in a swamp.

To understand the breadth of the distribution of the actual extraction of this local resource in Rus', it is enough, as in the case of "metallurgical surnames", simply to open any geographical map and look at the names of Russian, Ukrainian, Belarusian or Lithuanian villages.
And immediately you will be struck by a huge number of toponyms with the words Guta, Buda, Ruda. Here are their meanings:

Guta: glass factory
Ore: swamp iron mining
Buda: the extraction of potash from plant ash.

You will find such villages everywhere - in a wide belt in the Polesye swamps - from Brest to Sumy. There were plenty of sources of "bog ore" in Rus'. "Swamp iron" is generally formed almost everywhere where there is a transition from oxygen-containing soils to an anoxic layer (exactly at the junction of these two layers).
In swamps, this border is simply located, unlike other types of terrain, very close to the surface, therefore, there iron nodules can be dug literally with a shovel, only removing a thin layer of marsh vegetation.

This is how swamp iron looks unpretentious (bog iron) .
But it was it that saved Rus'.

Bog iron deposits themselves are classic placers.
Placers are usually much smaller deposits than ore bodies, their total volume rarely exceeds tens of thousands of tons (while ore deposits can contain millions and billions of tons of ore), but the mining of placers is usually much simpler than mining an ore body.
The placer can usually be developed almost with bare hands and with minimal crushing of the rock, since placers usually occur in already destroyed, sedimentary rocks.
This is generally a widespread practice: first placers are mined - then ores.
And - for all metals, minerals or compounds.

By the way, "wooden tin" (which I wrote about in the series about the Bronze Age Catastrophe) is also a placer.

However, it cannot be said that the mining of placers of swamp iron was a simple task.

Swamp iron was mined in three main ways.

The first one was that in the summer, bottom silt was scooped from rafts on swamp lakes and on rivers flowing from swamps. The raft was held in one place by a pole (one person) and another person pulled mud from the bottom with a scoop. The advantages of this method are simplicity, and low physical exertion on workers.
The disadvantages are a large amount of useless labor, since not only was waste rock scooped up with swamp iron, but in addition, large amounts of water had to be raised up along with silt. In addition, with a scoop it is difficult to choose the soil to a great depth.

The second way. In winter, in places where the channels froze to the bottom, ice was cut first, and then the bottom sediment containing bog iron was also cut down. The advantages of this method: the ability to select a large layer containing bog iron. Disadvantages: it is physically difficult to gouge ice and frozen ground. Mining is possible only to the depth of freezing.

The third method was the most common. On the shore near the channels or marsh lakes, a log house was assembled, as for a well, only large, for example, 4 by 4 meters. Then, inside the log house, they began to dig out, first, the covering layer of waste rock, gradually deepening the log house. Then the rock containing bog iron was also selected. Log rolls were added as the log house deepened.
Constantly flowing water was periodically scooped out. It was possible, of course, to simply dig without strengthening the walls with logs, but in the event of a very likely shedding of the eroded soil and workers falling asleep in the pit, it would hardly have been possible to save anyone - people would quickly choke and drown. Advantages of this method: the ability to select the entire layer containing bog iron, and lower labor costs compared to the second method. In addition, even before the start of mining, it was possible to approximately determine the quality of the raw materials being mined (“the inhabitants there also judge the goodness of the ore by the kind of trees growing on it; thus, the one found under birch and aspen is considered the best, because iron is softer from it, and in places where spruce grows, it is tougher and stronger").
Disadvantages: you have to work in the water all the time.

In general, the ancient Russian miners had a hard time. Now, of course, reenactors around the world are doing field trips and even digging holes in drier and more accessible places where you can easily get some swamp ore:

Children of reenactors are happy. In the 9th century, everything was, I think, different.

However, in order to understand the situation in Rus' in the 9th-12th centuries, one must understand scale of the fishery that was organized by our ancestors on such an overwhelmed resource as swamp placers.

After all, if the process of digging silt in the swamps itself did not leave behind any traces that can be traced through the centuries, then the subsequent processing of marsh iron left traces in the cultural layer, and even what!

After all, for the cheese-making process, which at that time was used in ancient Russian metallurgy and produced high-iron slag, it was necessary very rich iron ore. And limonite, as we remember, is a poor ore.
To obtain a good concentrate of limonite, it was necessary to pre-enrich the mined ores, both marsh and meadow. Therefore, ancient Russian metallurgists necessarily enriched swamp iron ores going into smelting.

The beneficiation operation was a very important technological condition for the production of iron in raw furnaces.
Later studies, through the analysis of historical monuments, revealed the following methods of ore dressing:

1) drying (weathering, within a month);
2) firing;
3) crushing;
4) washing;
5) screening.

Obtaining highly concentrated ore could not be limited to only one or two operations, but required systematic processing by all the indicated methods. An archaeologically well-known operation is the roasting of ore.
As you understand, firing also required high-quality fuel (charcoal), and also in considerable quantities.

During archaeological exploration near the village of Lasuny on the coast of the Gulf of Finland, a pile of burnt ore was discovered in one of the pits. For all operations of ore dressing, very simple equipment is required: for crushing ore - a wooden block and a mortar, and for sifting and washing - a wooden sieve (net of rods).
The disadvantage of burning swamp ore in fires and pits was the incomplete removal of water from it when burning large pieces and large losses when burning small pieces.

IN modern production, of course, enrichment is much simpler - finely crushed ore is mixed with the same ground coke and fed into an apparatus similar to a large meat grinder. The auger feeds the mixture of ore and coke onto a grate with holes no larger than 8 mm. Squeezing out through the holes, such a homogeneous mixture enters the flame, while the coke burns out, melting the ore, and in addition, sulfur is burned out of the ore, thus simultaneously desulphurizing the raw material.

After all, marsh iron, like coal, contains harmful impurities - sulfur and phosphorus. It was possible, of course, to find raw materials containing little phosphorus (well, relatively little - in the ore iron it is still always less than in the swamp). But to find swamp iron containing little of both phosphorus and sulfur was almost impossible. Therefore, in addition to the whole industry of mining swamp iron, an equally large-scale industry of its enrichment arose.

To understand the scope of this action, I will give one example: during excavations in Old Ryazan in 16 out of 19 urban dwellings traces of "home" cooking of iron in pots in an ordinary furnace were found.
Western European traveler Yakov Reitenfels, having visited Muscovy in 1670, wrote that "the country of the Muscovites is a living source of bread and metal."

So, in a bare place, with nothing under them but poor forest soils with stunted birch trees and peat bogs, suddenly our ancestors found a “gold mine” literally under their feet. And even though it was not a vein, but a placer and not gold, but iron, the situation did not change from this.

A country that is only just emerging has received its place in the world and a civilizational path that will lead it to the cannons of Balaklava, to the T-Z4 tank and to the Topol-M ICBM.
Resources. Job. Production. Weapon.

Because having resources - you inevitably come to arms. Or - someone else comes for your resources.
The Iron Age began in Rus'.
Century - or rather - the millennium of Russian weapons.

A millennium in which the sword will rise - and fall again, after another enemy is defeated and thrown away from birch forests and peat bogs.

And the enemies were not long in coming.
Indeed, in the 10th century, the Iron Age arms race was already gaining momentum.

Leaders:

A.M. fool

V.F. Kuznetsova

Introduction

We have long been interested in the history of the development of metallurgy in our region, this history is connected mainly with the Batashov brothers, who owned factories in our district. In previous years, we have been researching their factories in Ilev, Snoved, as well as in Ryazan and Vladimir regions. It is known that there was a complete metallurgical cycle at the Batashov factories: from ore mining to the manufacture of iron products. In the process of studying the history of factories, we were very interested in the development of metallurgy technology, and we devoted this work to the ancient process of obtaining iron.

Development of iron metallurgy

The first iron objects known to archaeologists date back to the 10th century BC. The first iron was valued very dearly and was not immediately used for the manufacture of tools. The most ancient method of obtaining iron from ore was the so-called raw-blast method, in which iron ore and coal are loaded into a furnace or furnace, during the combustion of which iron is partially reduced from the ore. Raw, unheated air was pumped into the forge, hence the name of the technique itself. Melting in the hearth of crushed iron ore mixed with charcoal took place at a high temperature. As the coal burnt out, the solid grains of iron, recovered from the ore, descended to the bottom of the furnace and, when welded, formed a spongy clot called kritsa. To compact the metal, the frozen kritsa taken out of the forge was repeatedly forged, obtaining a monolithic piece of iron weighing up to 5-6 kg. Commodity kritsa metallurgy was given a rounded cake shape.

Subsequently, in the production of iron, primitive bloomery furnaces were replaced by blast furnaces: these furnaces are larger, more productive, and they also achieve a higher temperature. The product of the blast furnace is pig iron (iron with a high carbon content), which is then processed into iron or steel.

Goals and objectives of the work

Goal of the work: to reconstruct the raw iron production method in modern conditions.

Tasks:

1) Find the ore needed to smelt iron.

2) Build a furnace that is as close as possible to the ancient samples.

3) Carry out the melting process.

4) Analyze the obtained samples.

Description of iron production in the literature

One of the sources by which we restored the ancient method of obtaining iron was Jules Verne's book "The Mysterious Island". The book describes how several people ended up on a desert island in the same clothes and gradually created various amenities for themselves, including smelting iron for their own needs.

Their method of smelting was called "Catalan". It consisted of the following. “The Catalan way in the proper sense requires the construction of furnaces and crucibles in which ore and coal are laid in layers.” But the hero of the book, engineer Cyrus Smith, intended to do without these structures. He erected "a cubic structure of coal and ore and sent a jet of air into the center of it." “Coal, as well as ore, was easily collected nearby, directly from the surface of the earth. First, the ore was crushed into small pieces and cleaned of dirt by hand. Then the coal and ore were piled up layer by layer, as a charcoal-burner does with a tree he wants to burn. Thus, under the action of the air pumped by the bellows, the coal had to turn into carbon dioxide and then into carbon monoxide, which was to restore the magnetic iron ore, that is, to take away oxygen from it. Air blast was organized with the help of sealskin furs.

Iron was obtained, but “it proved difficult. It took all the patience, all the ingenuity of the colonists to successfully carry it out. In the end, it succeeded, and an iron ingot was obtained in a spongy state, which still had to be forged in order to expel liquid slag from it. In this way, a rough but usable metal was obtained.”

We tried to translate into reality what was described by Jules Verne. The main difference of our method was that we used an oven.

The process of obtaining iron

Ore mining

On June 3, 2010, we went to explore the vicinity of the village of Elizarieva, where, as we knew, there were iron ore mines. From Sarov we got to the place in about 20 minutes. Having reached the place, we went to search for ore, which should have been located in the area of ​​old mines. We found most of the ore where there was no grass and a layer of soil was removed (fire-fighting trench) or rammed (road). It was in the trench that we found most of the ore of various sizes, up to 15 * 10 * 10 cm (approximately). Basically, the ore was gray and brown. Brown ore predominates. We collected a bucket of ore. We also saw about a dozen remnants of pipes that were covered and already overgrown with grass.

An old pipe near the village of Elizarieva

Iron ore

ore grinding

We decided to crush the ore to a size of no more than 1 cm 3 so that it would be easier to melt it. We crushed all the ore in the bucket and got about 3/5 of the bucket of crushed ore.

Furnace masonry

Fragments of silicate bricks were used for the furnace. The laying of the furnace was carried out using a mixture of cement and sand. We mixed the mortar and, row by row, laid the bricks in the oven, fixing them with mortar.

Solution preparation

Our oven

Fuse

The stove was preheated by burning wood in it for an hour and a half.

In a heated oven, we poured ore, and then charcoal, purchased in a store, in layers. We had to achieve a temperature of 900 degrees Celsius, so in addition to the conditions provided by nature, we had to use vacuum cleaners for blowing (imitation of furs). There were two vacuum cleaners and they turned on one by one, working for 30 minutes without a break. But after an hour of melting, the furnace began to crack, since the silicate brick could not withstand such high temperature. But despite the fact that it cracked, it did not crumble in 2 hours and 30 minutes of melting. During the melting process, we measured the temperature inside the furnace using a special device. It ranged from 800 to 1300 degrees Celsius. The whole preparation process took 4 hours.

Air blast. In the photo - Valentina Fedorovna Kuznetsova - the mistress of the vacuum cleaner

Temperature measurement using a pyrometer is carried out by Alexey Kovalev

Melting result

After dismantling the furnace the next day, we removed gray pieces from it with a faint metallic sheen.

Dismantling the furnace

Samples of received metal

Apparently, a metallurgical reaction took place (before and after)

Attempt to forge the resulting metal

Following the method described by Jules Verne, samples of the resulting metal had to be forged. To do this, we took them to the forge, where the blacksmith heated them in a furnace, but under his hammer our metal crumbled. An examination carried out in one of the VNIIEF laboratories showed that the resulting substance consists of 20% iron, and the rest is iron oxides.

Conclusion

We received the metal, but it turned out to be unsuitable for the manufacture of any products.

What was our possible error? We posted a description of our experience on the Internet and received many comments, some of which were valuable.

In particular, a user with the nickname 3meys told us:

“During bloomery smelting from ore, the temperature should be ~ 900 degrees and as little as possible unburned oxygen so that it does not oxidize the metal back.”

From this we conclude that we had a temperature slightly higher than necessary, and the reduced iron oxidized, which explains the fragility and porosity of the samples we obtained.

Nevertheless, we believe that we have achieved our goals - we carried out a smelting, as a result of which the metallurgical process was carried out. With the help of our experiment, we have come closer to understanding the ancient metallurgical production.

Thanks

The author and supervisors would like to thank Aleksey Evgenievich Kovalev, employees of the Institute of Explosion Physics RFNC-VNIIEF, for temperature measurements using a pyrometer, and Mikhail Igorevich Tkachenko, for X-ray diffraction analysis of ore and metal.

Bibliography

1. Mikhailov L. (supervisors A.M. Podurets, V.F. Kuznetsova). Unzhensky Batashev factories. Report at the School Khariton Readings, Sarov, 2010.
2. Voskoboynikov V.G., Kudrin V.A., Yakushev A.M. General metallurgy. Moscow, 2002.
3. http://erzya.ru/culture/57-krichniki.html
4. Verne J. Mysterious Island. Minsk, 1984.
5. http://leprosorium.ru/comments/948169.

Application

Comparison of technology today, in the XVII - XVIII centuries (yesterday) and ours

Ore mining:

Ore grinding:

Receiving coal:

Iron ore is obtained in the usual way: open pit or underground mining and subsequent transportation for initial preparation, where the material is crushed, washed and processed.

The ore is poured into a blast furnace and blasted with hot air and heat, which turns it into molten iron. It is then removed from the bottom of the furnace into molds known as pigs, where it is cooled to produce pig iron. It is turned into wrought iron or processed into steel in several ways.

What is steel?

In the beginning there was iron. It is one of them. It can be found almost everywhere, in combination with many other elements, in the form of ore. In Europe, the beginning of work with iron dates back to 1700 BC.

In 1786, French scientists Berthollet, Monge and Vandermonde accurately determined that the difference between iron, cast iron and steel is due to different carbon content. Nevertheless, steel, made from iron, quickly became the most important metal of the Industrial Revolution. At the beginning of the 20th century, world steel production was 28 million tons, six times more than in 1880. By the beginning of World War I, its production was 85 million tons. Within a few decades, it practically replaced iron.

There are currently over 3,000 cataloged brands (chemical formulations), not counting those created to meet individual needs. All of them contribute to making steel the most suitable material for the challenges of the future.

Raw materials for steelmaking: primary and secondary

The smelting of this metal using many components is the most common method of extraction. Charge materials can be both primary and secondary. The main composition of the charge, as a rule, is 55% pig iron and 45% of the remaining scrap metal. Ferroalloys, converted cast iron and commercially pure metals are used as the main element of the alloy, as a rule, all types of ferrous metal are classified as secondary.

Iron ore is the most important and basic raw material in the iron and steel industry. It takes about 1.5 tons of this material to produce a ton of pig iron. About 450 tons of coke are used to produce one ton of pig iron. Many metallurgical plants even use

Water is an important raw material for ferrous metallurgy. It is mainly used for quenching coke, cooling blast furnaces, generating steam in the doors of hydraulic equipment and removing Wastewater. It takes about 4 tons of air to produce a ton of steel. The flux is used in the blast furnace to extract contaminants from smelter ore. Limestone and dolomite combine with the extracted impurities to form slag.

Both blast and steel furnaces are lined with refractories. They are used for facing furnaces intended for iron ore smelting. Silicon dioxide or sand is used for molding. For the production of steel of various grades, aluminum, chromium, cobalt, copper, lead, manganese, molybdenum, nickel, tin, tungsten, zinc, vanadium, etc. are used. Among all these ferroalloys, manganese is widely used in steelmaking.

Iron waste obtained from the dismantled structures of factories, machinery, old vehicles, etc., is recycled and widely used in this industry.

Cast iron for steel

Steel is smelted using cast iron much more often than with other materials. Cast iron is a term that usually refers to gray iron, however it is also identified with a large group of ferroalloys. Carbon makes up about 2.1 to 4% by weight, while silicon typically makes up 1 to 3% by weight in the alloy.

The smelting of iron and steel takes place at a melting point between 1150 and 1200 degrees, which is about 300 degrees lower than the melting point of pure iron. Cast iron also exhibits good fluidity, excellent machinability, resistance to deformation, oxidation and casting.

Steel is also an alloy of iron with a variable carbon content. The carbon content of steel is 0.2 to 2.1 wt%, and it is the most economical alloying material for iron. The smelting of steel from cast iron is useful for a variety of engineering and structural purposes.

Iron ore for steel

The steelmaking process begins with the processing of iron ore. The rock containing iron ore is crushed. Ore is mined using magnetic rollers. Fine-grained iron ore is processed into coarse-grained lumps for use in a blast furnace. Coal is purified from impurities into which gives an almost pure form of carbon. The mixture of iron ore and coal is then heated to produce molten iron or pig iron, from which steel is made.

In the main oxygen furnace, molten iron ore is the main raw material and is mixed with various amounts of scrap steel and alloys to produce various grades of steel. In an electric arc furnace, recycled steel scrap is melted directly into new steel. About 12% of steel is made from recycled material.

Smelting technology

Smelting is a process by which a metal is obtained either as an element or as a simple compound from its ore by heating above its melting point, usually in the presence of oxidizing agents such as air or reducing agents such as coke.

In steelmaking technology, a metal that is combined with oxygen, such as iron oxide, is heated to a high temperature, and the oxide is formed in combination with carbon in the fuel, which is released as carbon monoxide or carbon dioxide.
Other impurities, collectively referred to as strands, are removed by adding a stream with which they combine to form slag.

Modern steel melting uses a reverberatory furnace. The concentrated ore and stream (usually limestone) are loaded at the top, while the molten matte (a combination of copper, iron, sulfur and slag) is drawn from the bottom. A second heat treatment in a converter furnace is necessary to remove iron from the matte surface.

Oxygen convector method

The basic oxygen process is the world's leading steelmaking process. The world production of converter steel in 2003 amounted to 964.8 million tons or 63.3% of the total production. Converter production is a source of environmental pollution natural environment. The main problems of this are the reduction of emissions, discharges and reduction of waste. Their essence lies in the use of secondary energy and material resources.

Exothermic heat is generated by oxidation reactions during blowdown.

The main process of steel smelting using own reserves:

• Molten iron (sometimes called hot metal) from a blast furnace is poured into a large refractory lined container called a ladle.
• The metal in the ladle is sent directly to the main steel production or pre-treatment stage.
• High purity oxygen at a pressure of 700-1000 kilopascals is injected at supersonic speed onto the surface of the iron bath through a water-cooled lance that is suspended in the vessel and held a few feet above the bath.

The pretreatment decision depends on the quality of the hot metal and the desired final steel quality. The very first removable bottom converters that can be detached and repaired are still in use. The spears used for blowing have been changed. To prevent jamming of the lance during blowing, slotted collars with a long tapering copper tip were used. The tips of the tip, after combustion, burn off the CO formed by blowing into CO 2 and provide additional heat. Darts, refractory balls and slag detectors are used to remove slag.

Oxygen convector method: advantages and disadvantages

It does not require the cost of gas purification equipment, since dust formation, i.e. iron evaporation, is reduced by 3 times. Due to the decrease in the yield of iron, an increase in the yield of liquid steel by 1.5 - 2.5% is observed. The advantage is that the blowing intensity in this method increases, which makes it possible to increase the performance of the converter by 18%. The quality of the steel is higher because the temperature in the blowing zone is reduced, which leads to a decrease in the formation of nitrogen.

The disadvantages of this method of steelmaking have led to a decrease in demand for consumption, since the level of oxygen consumption increases by 7% due to the high consumption of fuel combustion. There is an increased hydrogen content in the recycled metal, which is why it takes some time after the end of the process to carry out a purge with oxygen. Among all methods, the oxygen-converter method has the highest slag formation, the reason is the inability to monitor the oxidation process inside the equipment.

open-hearth method

The open-hearth process, for most of the 20th century, was the main part of the processing of all steel made in the world. William Siemens, in the 1860s, sought a means of raising the temperature in a metallurgical furnace, resurrecting an old proposal to use the waste heat generated by the furnace. He heated the brick to a high temperature, then used the same path to introduce air into the kiln. The preheated air significantly increased the temperature of the flame.

Natural gas or pulverized heavy oils are used as fuel; air and fuel are heated before combustion. The furnace is loaded with liquid pig iron and steel scrap along with iron ore, limestone, dolomite and fluxes.

The oven itself is made of highly refractory materials, such as magnesite bricks for hearths. Open hearth furnaces weigh up to 600 tons and are usually installed in groups so that the massive auxiliary equipment needed to charge the furnaces and process liquid steel can be effectively used.

Although the open hearth process has been almost completely replaced in most industrialized countries by the basic oxygen process and the electric arc furnace, it makes about 1/6 of all steel produced worldwide.

Advantages and disadvantages of this method

The advantages include ease of use and ease of production of alloy steel with various additives that give the material various specialized properties. The necessary additives and alloys are added immediately before the end of the smelting.

The disadvantages include reduced efficiency, compared with the oxygen-converter method. Also, the quality of the steel is lower compared to other metal smelting methods.

Electric steelmaking method

The modern method of smelting steel using one's own reserves is a furnace that heats a charged material with an electric arc. Industrial arc furnaces range in size from small units with a capacity of about one ton (used in foundries for the production of iron products) to 400 tons units used in secondary metallurgy.

Arc furnaces used in research laboratories may have a capacity of only a few tens of grams. Industrial electric arc furnace temperatures can be up to 1800 °C (3.272 °F), while laboratory installations can exceed 3000 °C (5432 °F).

Arc furnaces differ from induction furnaces in that the charging material is directly exposed to an electric arc, and the current in the terminals passes through the charged material. The electric arc furnace is used for steel production, consists of a refractory lining, usually water-cooled, large size, covered with a retractable roof.

The furnace is mainly divided into three sections:

• Shell consisting of side walls and lower steel bowl.
• The hearth consists of a refractory material that extends the lower bowl.
• A roof with a refractory lining or water cooling can be made in the form of a ball section or in the form of a truncated cone (conical section).

Advantages and disadvantages of the method

This method occupies a leading position in the field of steel production. The steel smelting method is used to create high-quality metal, which is either completely devoid of, or contains a small amount of undesirable impurities such as sulfur, phosphorus and oxygen.

The main advantage of the method is for heating, so you can easily control the melting temperature and achieve an incredible rate of heating of the metal. Automated work will be a pleasant addition to the excellent opportunity for high-quality processing of various scrap metal.

The disadvantages include high power consumption.

The process of producing iron begins with the smelting of pig iron, which contains a significant amount of carbon (which enters the pig iron from the coke or charcoal used to smelt the ore). Cast iron is very hard, but brittle. Carbon can be completely removed from cast iron. The resulting wrought iron is a malleable but relatively soft material. A certain amount of carbon is again introduced into it and as a result a steel is obtained that has sufficient toughness and at the same time sufficient hardness.

Calculate the amount of electricity required to smelt 1 ton of pig iron in an electric furnace, if we accept a) the iron reduction reaction in the furnace proceeds according to the scheme

All metallurgical processes can be divided into primary and secondary. Under the primary processes understand the extraction of metal from various natural or artificial raw materials (blast-furnace process, direct production of iron, smelting of black and

In all smelting processes, liquid steel contains a small amount of dissolved oxygen (up to 0.1%). During the crystallization of steel, oxygen interacts with dissolved carbon, forming carbon monoxide (P). This gas (as well as some other gases dissolved in liquid steel) is released from the steel in the form of bubbles. In addition, oxides of iron and metal impurities are released along the grain boundaries of steel. All this leads to a deterioration in the mechanical properties of steel.

Manganese is mined in the form of ferromanganese containing 85-88% manganese, up to 7% carbon, the rest is iron. The smelting of ferromanganese from a mixture of manganese and iron ores is carried out using coal as a reducing agent. MnOz reduction reaction equation

When carbon and impurities are oxidized, part of the metallic iron is oxidized to FeO oxide (metal waste). To reduce the loss of metal, it is regenerated, that is, reduced to iron. In accordance with this, in the process of steel smelting, two consecutive periods are distinguished - oxidation and reduction, which can be represented by the scheme

B. The recovery period of melting in oxygen-converter smelting of steel is spatially separated from the oxidation period and proceeds after the release of steel from the converter in the ladle. Simultaneously with the reduction of iron oxide FeO in

The technological process of processing iron ore, coal, limestone and hydrocarbon fuels in final product can be divided into 3-4 main stages, which are carried out separately to obtain a specific product, which is processed into a new type of product at the next stage. The various process steps can take place in the same process unit. This will help not only save energy and transportation costs, but also simplify the process. The main technological stages in the production of iron and steel are as follows: preparation of raw materials (coking of coal, roasting of limestone, production of iron ore sinter and pellets) production of pig iron (blast furnace smelting, production of sponge iron by direct reduction of iron) oxygen converters) rolled products (continuous casting of blanks, rolling of section steel, production of pipes, forgings).

The first metals used were probably gold and silver, since they can be found in nature in a free state. They were mainly used in decorative items. Copper began to be used around 8000 BC for the manufacture of tools, weapons, kitchen utensils and jewelry. Around 3800 BC, bronze was invented - an alloy of copper and tin. As a result, humanity moved from the Stone Age to the Bronze Age. Then a method of smelting iron was found, and the Iron Age began. As people accumulated their chemical experience, the range of useful materials that man learned to obtain by processing a wide variety of ores expanded.

Pyrometallurgical methods of copper smelting are inappropriate for processing poor ores that cannot be enriched. This category includes oxidized ores, both poor and richer, as well as dumps of poor sulphide ores and tailings from enrichment. For this raw material, methods are used to leach copper from ore and extract it from solutions by iron precipitation or electrolysis with insoluble anodes.

The most common ore from which chromium is obtained is chromium iron ore FeCgaO. Calculate the content (in percent) of impurities in the ore, if it is known that 240 kg of ferrochrome (an alloy of iron with chromium) containing 65% chromium was obtained from 1 ton of it during smelting.

What is the relative content by weight of iron in this ore (in percent) How much carbon is needed to smelt iron from

With the complex use of polymetallic sulfide ores, various non-ferrous metals, sulfuric acid and iron oxide are obtained for iron smelting. Examples of the complex use of natural materials, which are mixtures of organic substances, can be coal coking with accompanying chemical industries, oil, shale, peat and wood processing. Hundreds of products are obtained from each type of fuel. Previously, when coal was coked, the only product of this process was coke, the gas was burned in furnaces, and the tar was thrown away. At present, benzene hydrocarbons, ammonia, hydrogen sulfide and other valuables are isolated from coke oven gas.

Glass melting. Glass can be transparent or translucent, colorless or colored. It is a product of high-temperature remelting of a mixture of silicon (quartz or sand), soda and limestone. To obtain specific or unusual optical and other physical properties other materials (aluminum, potash, sodium borate, lead silicate or barium carbonate) are used as an additive to the melt or as a substitute for part of the soda and limestone in the charge. Colored melts are formed as a result of the addition of iron or chromium oxides (yellow or green), cadmium sulfide (orange), cobalt oxides (blue), manganese (magenta) and nickel (violet). The temperatures to which these ingredients must be heated are in excess of 1500°C. Glass does not have a specific melting point and softens to a liquid state at a temperature of 1350-1600 °C. Energy consumption even in well designed furnaces is about 4187 kJ/kg of glass produced. The required flame temperature (1800-1950 °C) is achieved by burning gas mixed with air, heated to 1000 °C in a regenerative heat exchanger, which is constructed from refractory bricks and heated by the exhaust products of combustion. The gas is blown into the hot air flow through the side walls of the upper head of the regenerator, which is the main combustion chamber, and the combustion products, having given off heat to the glass mass, leave the furnace and go into the regenerator located opposite. When the combustion air preheating temperature decreases significantly, the air and combustion products flows are reversed and the gas will be fed into the air flow heated in the opposite regenerator.

Corona electrodes in vertical electrostatic precipitators are a thin round wire, a wire with small spikes, or a wire with a square or star-shaped cross section. Due to the fact that the discharge electrodes are often more than 6 m long, the round wire, while thin enough to provide a stable corona, may not be strong enough, especially as it is subjected to vibrations during shaking. In this regard, a wire of a larger caliber with a cross section in the form of a square or a star is used, with sharp edges that ensure the formation of a stable crown. Barbed wire electrodes are preferred in some electrostatic precipitators, and more recently they have been used to deposit iron oxide mist in oxy-fuel steelmaking.

The principle of using industrial waste (integrated use of raw materials, waste-free technology). Turning waste into by-products enables better use of raw materials, which in turn reduces product costs and prevents pollution environment. For example, non-ferrous metals, sulfur, sulfuric acid and iron oxide (III) are obtained from polymetallic sulfide ores during complex processing for iron smelting. The integrated use of raw materials is the basis for combining enterprises. At the same time, new industries arise that process waste from the main enterprise, which gives a high economic effect and is the most important element of chemicalization of the national economy.

Metals can be extracted from their ores directly by electrolytic or chemical reduction. Electrolytic reduction, which has already been discussed in Sec. 19.6 is used on an industrial scale to obtain the most active metals sodium, magnesium and aluminum. The less active metals copper, iron and zinc are produced commercially by chemical reduction, with most of the less active metals produced by high temperature molten reduction. Therefore, such processes are called smelting.

Carbon dioxide is formed from the reduction of iron oxide [equation (22.20)], as well as from the decomposition of limestone. But limestone plays a role in iron smelting not only as a supplier of carbon dioxide. The ore that is recovered usually contains

When iron is smelted, slag floats on the surface of the molten metal, protecting it from oxidation by the incoming air. The resulting iron and slag are periodically removed from the furnace. Iron obtained in a blast furnace is called cast iron and contains up to 5% carbon and up to 2% other impurities, silicon, phosphorus and sulfur.

When iron is smelted in a blast furnace, a variety of chemical processes take place, in particular, the reduction of iron oxide (III) with carbon monoxide (II), which can be expressed by the equation

Chemical reactions in the smelting of iron and steel occur mainly in solutions. Liquid iron and steel are solutions of various elements in iron. In blast furnaces and steel-smelting furnaces, they interact with liquid slag - a solution of oxides.

Selenium and tellurium occur in such rare minerals as C3Se, Pb5e, A25e, Cu2Te, PbTe, A2Te, and AuTe, and also as impurities in sulfide ores of copper, iron, nickel, and lead. From an industrial point of view, important sources of extraction of these elements are copper ores. In the process of their roasting during the smelting of metallic copper most of selenium and tellurium remains in copper. During the electrolytic purification of copper, described in Sec. 19.6, impurities such as selenium and tellurium, along with precious metals gold and silver accumulate in the so-called anode sludge. When the anode sludge is treated with concentrated sulfuric acid at approximately 400°C, selenium is oxidized to selenium dioxide, which sublimates from the reaction mixture

In some cases (for example, when smelting transformer steel), it is necessary to achieve a very low carbon concentration of 0.002-0.003%. It can be seen from the above equation that for this it is necessary to lower pco. The use of vacuum furnaces in modern metallurgy makes it possible to smelt iron and steel with a minimum carbon content.

When iron is smelted from magnetic iron ore, one of the reactions occurring in a blast furnace is expressed by the equation Res04 + CO = ZReO + Oj Using the data in Table. 5 applications, determine the thermal effect of the reaction. In what direction will the equilibrium of this reaction shift if the temperature rises?

Magnetic iron ore Iron oxide ore iron content 50-70%, mainly composed of iron oxide(11, ill) Pb3O, Raw material for iron production, additive in steel production (smelting)

U-88. From 1 ton of chromium iron ore, Fe(CrO2)a was formed during the smelting of 240 kg of an alloy of iron with chromium - ferrochromium, containing 65% chromium. Calculate the percentage of impurities in the ore.

When smelting high-chromium steels of the Kh18N10T type, a peculiar skull is formed on the working surface of the refractory lining with a high content of AlA TiO. .

As a result, two liquid layers are formed in the furnace - a lighter slag on top, and a melt consisting of FeS and U2S (matte) below. The slag is drained, and the liquid matte is poured into a converter, into which a flux is added and air is blown in. The converter for copper smelting is similar to that used for steel production, only air is supplied to it from the side (when air is supplied from below, the copper is strongly cooled and solidifies). Molten copper is formed in the converter, iron sulfide turns into oxide, which turns into slag

The final sulfur content in the calcined coke from Arlan oil tar is the same as in the coke from the cracked residue of Romashkino oil, i.e., less than 1%. The rest of the indicators are basically the same, except for the content of vanadium (1.5 times higher for Arlan coke), iron and other metals. The increased content of vanadium in desulfurized coke is explained by its high content in Arlan oil. Because of this, such coke cannot be used in the aluminum industry. When smelting aluminum, vanadium, like other metals, is made from coke

The paper describes the effect of manganese on sulfide cracking of steels. Manganese in an amount from 1 to 167 o was introduced in smelting into armo-iron containing 0.04% C, into steel 20, and into steel U8. The research results are given in table. 1.2, from which it can be seen that the alloying of steels with manganese increases their susceptibility to cracking in a hydrogen sulfide-containing environment, and the negative effect of manganese depends on the carbon content in the steel. So, the negative effect of manganese for armo-iron, steel 20 and steel U8 begins to manifest itself at its content of 3 2 n 1%, respectively. The negative effect of manganese on the cracking of steels is associated by the authors with the appearance of

In metallurgy great importance has an alloy of iron with silicon - ferrosilicon. It is used for the deoxidation of many steel grades and for the production of silicon-carbon ferroalloys. Ferrosilicon with a content of 9-17% 51 is smelted in blast furnaces from quartz, iron shavings and coke. Ferrosilicon with a high silicon content is a promising material for the manufacture of chemical equipment parts due to its exceptional acid resistance. It is widely used as a reducing agent in the smelting of silicomanganese, ferrotungsten, ferromolybdenum. The addition of silicon to steel in the form of ferrosilicon during its smelting gives it elasticity and increases resistance to corrosion.

Some features of a typical smelting process can be illustrated by the reduction of iron. Continuous smelting of iron is carried out in a special reactor called a blast furnace; its schematic representation is shown in fig. 22.16. A mixture of coke, limestone and crushed ore, usually containing FejOs, is loaded into the blast furnace from above. (Coke is a solid residue obtained from the coking of natural fuels, mainly coal, in order to remove volatile components from them.) Heated air, sometimes enriched with oxygen, is forced into the furnace from below. To obtain 1 ton of iron, approximately 2 tons of ore, 1 ton of coke and 0.3 tons of limestone are needed. One blast furnace can produce up to 2000 tons of iron per day. The air injected into the furnace reacts with carbon, forming CO. In this case, such an amount of heat is released that a temperature of the order of 1500 ° C develops in the lower part of the furnace. The reduction of metallic iron can be described by the reactions

How many tons of magnetic iron ore, consisting of 90% FegOi, can be produced by smelting 2 tons of pig iron with 93% iron content, if the product yield is 92%

The introduction of silicon into steel and cast iron is accompanied by the formation of iron silicides (ferrosilicon FeSi). Cast iron containing 15-17% silicon is acid-resistant. Ferrosilicon is added to steel during smelting to remove the oxygen it contains.

STEIN is an intermediate product in the smelting of certain non-ferrous metals (Cu, N1, Pv, etc.) from their sz lipid ores. Sh. - an alloy of iron sulfide with sulfides of the obtained metals (for example, Cu, 8).

The phenomenon of lowering the melting point of solutions is of great importance both in nature and in technology. For example, the smelting of pig iron from iron ore is greatly facilitated by the fact that the melting point of iron is lowered by about 400 ° C due to the fact that carbon and other elements dissolve in it. The same applies to the refractory oxides that make up the waste rock, which together with fluxes (CaO) form a solution (slag) that melts at a relatively low temperature. This makes it possible to carry out a continuously periodic process in blast furnaces, releasing liquid pig iron and slag from them. ]