Metal ores and their classification. Metal ores Composition of iron ore
Iron ore is the main raw material for the global metallurgical industry. The economy largely depends on the market for this mineral. different countries, therefore, mine development is receiving increased attention throughout the world.
Ore: definition and features
Ores are rocks that are used for processing and extracting the metals they contain. The types of these minerals differ in origin, chemical content, concentration of metals and impurities. The chemical composition of the ore contains various oxides, hydroxides and carbon dioxide salts of iron.
Interesting! Ore has been in demand on the farm since ancient times. Archaeologists were able to find out that the manufacture of the first iron objects dates back to the 2nd century. BC. This material was first used by the inhabitants of Mesopotamia.
Iron- widespread in nature chemical element. Its content in the earth's crust is about 4.2%. But in its pure form it is almost never found, most often in the form of compounds - in oxides, iron carbonates, salts, etc. Iron ore is a combination of minerals with a significant amount of iron. IN national economy The use of ores containing more than 55% of this element is considered economically justified.
What is made from ore
Iron ore industry is a metallurgical industry that specializes in the extraction and processing of iron ore. The main purpose of this material today is the production of cast iron and steel.
All products made from iron can be divided into groups:
- Pig iron with high carbon concentration (above 2%).
- Cast iron.
- Steel ingots for the production of rolled products, reinforced concrete and steel pipes.
- Ferroalloys for steel smelting.
What is ore needed for?
The material is used for smelting iron and steel. Today there is practically no industrial sector that can do without these materials.
Cast iron is an alloy of carbon and iron with manganese, sulfur, silicon and phosphorus. Cast iron is produced in blast furnaces, where at high temperatures ah ore is isolated from iron oxides. Almost 90% of the resulting cast iron is marginal and is used in steel smelting.
Various technologies are used:
- electron beam melting to obtain pure high-quality material;
- vacuum processing;
- electro-slag remelting;
- steel refining (removal of harmful impurities).
The difference between steel and cast iron is the minimum concentration of impurities. Oxidative smelting in open-hearth furnaces is used for purification.
Steel itself High Quality melted in induction electric ovens with extremely high temperatures.
Ore differs in the concentration of the element it contains. It can be enriched (with a concentration of 55%) and poor (from 26%). It is advisable to use low-grade ores in production only after enrichment.
Based on their origin, the following types of ores are distinguished:
- Magmatogenous (endogenous) - formed under the influence of high temperature;
- Surface - settled remains of the element on the bottom of sea basins;
- Metamorphogenic - obtained under the influence of extremely high pressure.
Main mineral compounds containing iron:
- Hematite (red iron ore). The most valuable source of iron with an element content of 70% and a minimum concentration of harmful impurities.
- Magnetite. A chemical element with a metal content of 72% is distinguished by high magnetic properties and is mined from magnetic iron ores.
- Siderite (iron carbonate). There is a high content of waste rock, the iron itself is about 45-48%.
- Brown iron ores. A group of aqueous oxides with a low percentage of iron, with admixtures of manganese and phosphorus. An element with such properties is characterized by good recoverability and porous structure.
The type of material depends on its composition and the content of additional impurities. The most common red iron ore with high percentage iron can be found in different states - from very dense to dusty.
Brown iron ores have a loose, slightly porous structure of brown or yellowish color. Such an element often requires enrichment, but is easily processed into ore (high-quality cast iron is obtained from it).
Magnetic iron ores are dense and granular in structure, looking like crystals embedded in the rock. The color of the ore is characteristic black-blue.
How ore is mined
Mining iron ore is difficult technical process, which involves diving into the bowels of the earth to search for minerals. Today, there are two methods of ore mining: open and closed.
Open (quarry method) is a common and safest option compared to closed technology. The method is relevant for those cases when work area none hard rocks, but not nearby settlements or engineering systems.
First, a quarry up to 350 meters deep is dug, after which iron is collected and removed from the bottom by large machines. After extraction, the material is sent on diesel locomotives to steel and iron factories.
Quarries are dug using excavators, but this process takes a lot of time. As soon as the machine reaches the first layer of the mine, the material is submitted for examination to determine the percentage of iron content and the feasibility of further work (if the percentage is above 55%, work in this area continues).
Interesting! Compared to the closed method, mining in quarries costs half as much. This technology does not require the construction of mines or the creation of tunnels. At the same time, the efficiency of work in open pits is several times higher, and the loss of material is five times less.
Closed mining method
Mine (closed) ore mining is used only if it is planned to maintain the integrity of the landscape in the area where ore deposits are being mined. This method is also relevant for work in mountainous areas. In this case, a network of tunnels is created underground, which leads to additional costs - the construction of the mine itself and the complex transportation of metal to the surface. Most main drawback — high risk for the lives of workers, the mine may collapse and block access to the surface.
Where is ore mined?
Iron ore mining is one of the leading areas of the economic complex of the Russian Federation. But despite this, Russia's share in world ore production is only 5.6%. World reserves amount to about 160 billion tons. The volume of pure iron reaches 80 billion tons.
Countries rich in ores
The distribution of minerals by country is as follows:
- Russia - 18%;
- Brazil - 18%;
- Australia - 13%;
- Ukraine - 11%;
- China - 9%;
- Canada - 8%;
- USA - 7%;
- other countries - 15%.
Significant deposits of iron ore have been noted in Sweden (the cities of Falun and Gellivar). Found in America a large number of ore in Pennsylvania. In Norway, the metal is mined in Persberg and Arendali.
Ores of Russia
The Kursk magnetic anomaly is a large deposit of iron ore in the Russian Federation and in the world, in which the volume of unrefined metal reaches 30,000 million tons.
Interesting! Analysts note that the scale of mineral extraction at the KMA mines will continue until 2020, and there will be a decline in the future.
Mine area Kola Peninsula is 115,000 sq. km. Iron, nickel, copper ore, cobalt and apatites.
The Ural Mountains are also among the largest ore deposits in the Russian Federation. The main development area is Kachkanar. The volume of ore minerals is 7000 million tons.
The metal is mined in smaller quantities in the West Siberian basin, Khakassia, the Kerch basin, Zabaikalsk and the Irkutsk region.
Iron ore began to be mined by humans many centuries ago. Even then, the benefits of using iron became obvious.
Finding mineral formations containing iron is quite easy, since this element makes up about five percent of the earth's crust. Overall, iron is the fourth most abundant element in nature.
It is impossible to find it in its pure form; iron is found in certain quantities in many types of rocks. Iron ore has the highest iron content, the extraction of metal from which is the most economically profitable. The amount of iron it contains depends on its origin, the normal proportion of which is about 15%.
Chemical composition
The properties of iron ore, its value and characteristics directly depend on its chemical composition. Iron ore may contain different quantity iron and other impurities. Depending on this, there are several types:
- very rich, when the iron content in the ores exceeds 65%;
- rich, the percentage of iron in which varies from 60% to 65%;
- average, from 45% and above;
- poor, in which the percentage of useful elements does not exceed 45%.
The more by-products there are in iron ore, the more energy is needed to process it, and the less efficient the production of finished products is.
The composition of a rock can be a combination of various minerals, waste rock and other by-products, the ratio of which depends on its deposit.
Magnetic ores are distinguished by the fact that they are based on an oxide that has magnetic properties, but when heated strongly, they are lost. The amount of this type of rock in nature is limited, but the iron content in it can be as good as red iron ore. Externally, it looks like solid black-blue crystals.
Spar iron ore is an ore rock based on siderite. Very often it contains a significant amount of clay. This type of rock is relatively difficult to find in nature, which, coupled with its low iron content, makes it rarely used. Therefore, classify them as industrial types ores is impossible.
In addition to oxides, nature contains other ores based on silicates and carbonates. The amount of iron content in a rock is very important for its industrial use, but also important is the presence of beneficial by-elements such as nickel, magnesium, and molybdenum.
Applications
The scope of application of iron ore is almost completely limited to metallurgy. It is used mainly for smelting cast iron, which is mined using open-hearth or converter furnaces. Today, cast iron is used in various spheres of human activity, including in most types of industrial production.
Various iron-based alloys are no less used - steel is the most widely used due to its strength and anti-corrosion properties.
Cast iron, steel and various other iron alloys are used in:
- Mechanical engineering, for the production of various machines and devices.
- Automotive industry, for the manufacture of engines, housings, frames, as well as other components and parts.
- Military and missile industry, in the production of special equipment, weapons and missiles.
- Construction, as a reinforcing element or construction of load-bearing structures.
- Light and food industries, as containers, production lines, various units and devices.
- Mining industry, as special machinery and equipment.
Iron ore deposits
The world's iron ore reserves are limited in quantity and location. Territories of accumulation of ore reserves are called deposits. Today, iron ore deposits are divided into:
- Endogenous. They are characterized by a special location in earth's crust, usually in the form of titanomagnetite ores. The shapes and locations of such inclusions are varied, they can be in the form of lenses, layers located in the earth's crust in the form of deposits, volcanic deposits, in the form of various veins and other irregular shapes.
- Exogenous. This type includes deposits of brown iron ores and other sedimentary rocks.
- Metamorphogenic. Which include quartzite deposits.
Deposits of such ores can be found throughout our planet. Largest quantity deposits are concentrated on the territory of the post-Soviet republics. Especially Ukraine, Russia and Kazakhstan.
Countries such as Brazil, Canada, Australia, USA, India and South Africa have large iron reserves. At the same time, in almost every country globe We have our own developed deposits, and if there is a shortage of them, the rock is imported from other countries.
Iron ore beneficiation
As stated, there are several types of ores. Rich ones can be processed directly after extraction from the earth's crust, others need to be enriched. In addition to the beneficiation process, ore processing includes several stages, such as sorting, crushing, separation and agglomeration.
Today there are several main methods of enrichment:
- Flushing.
It is used to clean ores from by-products in the form of clay or sand, which are washed out using jets of water under high pressure. This operation makes it possible to increase the amount of iron content in low-grade ore by approximately 5%. Therefore, it is used only in combination with other types of enrichment.
- Gravity cleaning.
It is carried out using special types of suspensions, the density of which exceeds the density of waste rock, but is inferior to the density of iron. Under the influence of gravitational forces, the by-products rise to the top, and the iron falls to the bottom of the suspension.
- Magnetic separation.
The most common beneficiation method, which is based on different levels of perception by ore components of the influence of magnetic forces. Such separation can be carried out with dry rock, wet rock, or in an alternate combination of its two states.
To process dry and wet mixtures, special drums with electromagnets are used.
- Flotation.
For this method, crushed ore in the form of dust is dipped into water with the addition of a special substance (flotation reagent) and air. Under the influence of the reagent, the iron joins the air bubbles and rises to the surface of the water, while the waste rock sinks to the bottom. Components containing iron are collected from the surface in the form of foam.
Send your good work in the knowledge base is simple. Use the form below
Students, graduate students, young scientists who use the knowledge base in their studies and work will be very grateful to you.
Posted on http://www.allbest.ru/
Metal ores and their classification
Metal Ore is a mineral containing valuable metals in quantities that are beneficial for industrial processing.
Ferrous metals include iron, manganese, chromium, titanium, and vanadium. Iron ore deposits are classified as industrial when the metal content is at least several tens of millions of tons and the ore bodies are shallow. IN large deposits The iron content amounts to hundreds of millions of tons. The most ore (in million tons) is mined in China (250), Brazil (185), Australia (more than 140), Russia (78), the USA and India (60 each) and Ukraine (45).
Classification of ferrous metal ores:
b Hematite ores (red iron ores) are iron oxide with an iron content of 51...66%, moisture - 1.6...7%.
b Magnetite ores (magnetic iron ores) are complex iron oxides. The iron content ranges from 50...60%, moisture - 2...12%.
b Brown iron ores are iron hydroxide ores. The average iron content is 30-55%, moisture 8-18%.
b Iron pyrite (pyrite, sulfur pyrite) is a golden-yellow ore with a metallic luster, containing up to 44% iron and up to 52% sulfur. ore metal non-ferrous deposit
Non-ferrous metals are divided into two main groups:
· light (aluminum, magnesium, titanium);
· heavy (copper, zinc, lead, nickel, cobalt).
Among light non-ferrous metals, aluminum dominates in terms of production and consumption volumes. Russia has large reserves of non-ferrous metal ores. Their distinctive feature is the extremely low percentage of metal they contain. Therefore, the ores of almost all non-ferrous metals are enriched. The main reserves are located in the Urals, Western and Eastern Siberia, Far East and other regions of the country.
Classification of non-ferrous metal ores:
b Ferromanganese - an alloy containing more than 10% iron and less than 10% manganese
b Chrome ore contains 13-61% chromium, 4-25% aluminum, 7-24% iron, 10-32% magnesium and other components
b Bauxite ores contain 50-60% alumina, which contains up to 37% aluminum.
b Alumina is a product of bauxite processing, polydisperse powder white, due to the high content of aluminum oxide, it is the main raw material for the aluminum industry.
Methods for obtaining a useful element by chemical means.
· 1. Concentration
Many ores contain undesirable materials such as clay and granite, also called gangue. Thus, metal extraction consists of removing this waste rock.
· 2. In-situ leaching method
A method of extracting a mineral by selectively dissolving it with chemical reagents in an ore body at its location and extracting it to the surface. PV is used for the extraction of non-ferrous metals.
· 3. Recovery
Extracting metals in this way involves reducing their ores to a metallic state. Metals that exist naturally as oxide ores can be reduced using carbon or carbon monoxide.
· 4. Electrolysis
Metals belonging to the upper end of the voltage range are usually reduced by electrolysis of their molten ores. These metals include aluminum, magnesium and sodium.
· 5. Refining
Purification of metals from impurities using electrolysis, when the crude metal is the anode, and the purified metal is deposited on the cathode.
Posted on Allbest.ru
...Similar documents
Basic information about the in-situ leaching method. Natural demineralization of residual solutions. Uranium mining using underground leaching method. Obtaining metals from off-balance and lost ores from the bowels of the Earth. Factors of bacterial leaching.
abstract, added 05/20/2009
Application conditions and effectiveness of underground mechanical crushing of ore. Characteristics of crushing complex equipment. Mechanization of crushing in the conditions of the Gorno-Shorsky branch of OJSC "Evrazruda". Crusher selection, classification and application.
course work, added 11/01/2015
Analysis of the ore preparation process in the mining industry. Methods of mineral processing. Basic concepts and purpose of screening operations. Features of crushing and grinding processes. Selection of ore crushing technology and equipment.
course work, added 05/14/2014
Characteristics of indigenous gold ores. Study of ore dressing at the Muruntau deposit. Calculation of crushing scheme with selection of equipment. Material balance leaching of ore with cyanide solution. Calculation of product profitability and profit.
thesis, added 06/29/2012
Determination of the amount of ore and metal in the subsoil with clarification of the distribution of reserves by individual grades and by sections of the deposit. Determining the quality of ore and the degree of reliability and reliability of reserve calculation figures and the degree of exploration of the deposit.
presentation, added 12/19/2013
Violation of the geological structure of the subsoil. Overload earth's surface mineral processing products. Ores of ferrous and non-ferrous metals. Colored stones: diamond, malachite, emerald, rhodonite, charoite, amber and pearls. Construction minerals.
Along with fuels, there are so-called ore minerals. Ore is called rock, which is in large quantities contains certain elements or their compounds (substances). The most commonly used types of ores are iron, copper and nickel.
Ore that contains iron in such quantities is called chemical compounds that its extraction is possible and economically profitable. The most important minerals are: magnetite, magnetite, titanomagnetite, hematite and others. Iron ores differ in mineral composition, iron content, useful and harmful impurities, conditions of formation and industrial properties.
Iron ores are divided into rich (more than 50% iron), ordinary (50-25%) and poor (less than 25% iron). Depending on the chemical composition, they are used for smelting cast iron in its natural form or after enrichment. Iron ores used to make steel must contain certain substances in the required proportions. The quality of the resulting product depends on this. Some chemical elements (besides iron) can be extracted from the ore and used for other purposes.
Iron ore deposits are divided by origin. Usually there are 3 groups: magmatic, exogenous and metamorphogenic. They can be further divided into several groups. Magmatogenous are formed mainly when various compounds are exposed to high temperatures. Exogenous deposits arose in the valleys during the deposition of and. Metamorphogenic deposits are pre-existing sedimentary deposits that have been transformed under high temperature conditions. The largest amount of iron ore is concentrated in Russia.
The Kursk magnetic anomaly is the most powerful iron ore basin in the world. Ore deposits on its territory are estimated at 200-210 billion tons, which is about 50% of the iron ore reserves on the planet. It is located mainly in the Kursk, Belgorod and Oryol regions.
Nickel ore is an ore containing a chemical element in such quantities and chemical compounds that its extraction is not only possible, but also economically profitable. Typically these are deposits of sulfide (nickel content 1-2%) and silicate (nickel content 1-1.5%) ores. The most important are the frequently occurring ones: sulfides, hydrous silicates and nickel chlorites.
Copper ores are natural mineral formations in which the copper content is sufficient for the economic extraction of this metal. Of the many known copper-containing minerals, they are used in industrial scale about 17: native copper, bornite, chalcopyrite (copper pyrite) and others. Industrial significance have the following types of deposits: copper pyrites, skarn copper-magenetite, copper-titanium magnetite and porphyry copper.
They occur among volcanic rocks ancient period. During this period, numerous land and underwater forces operated. Volcanoes released sulfurous and hot waters saturated with metals - iron, copper, zinc and others. Of these on seabed and in the underlying rocks ores were deposited, consisting of sulfides of iron, copper and zinc, called pyrites. The main mineral of pyrite ores is pyrite, or sulfur pyrite, which makes up the predominant part (50–90%) of the volume of pyrite ores.
Most of the mined nickel is used for the production of heat-resistant, structural, tool, stainless steels and alloys. A small part of nickel is spent on the production of nickel and copper-nickel rolled products, for the manufacture of wire, tapes, various equipment for industry, as well as in aviation, rocket science, and in the production of equipment for nuclear power plants, manufacturing of radar instruments. In industry, nickel is alloyed with copper, zinc, aluminum, chromium and other metals.
From the sonorous Latin word “minera” - “stone that gives birth to metal” - the word “mineralogy” comes from. The origins of knowledge about stone were lost somewhere in the distance of the Paleolithic. The inexhaustible curiosity of our ancestors was combined with an insatiable desire to benefit from environment, and a naive tendency to deify nature - with a “blasphemous” desire to immediately use the power of the “gods” in action. Even the most formidable “deity” - fire - man risked bringing into his cave. And hard flint pebbles generously scattered by nature (these “cornerstones of history”), which were split open, revealing sharp edges, he turned into chisels, scrapers, spearheads and arrows.
Our Stone Age ancestor Homohabilis (handy man) *, who mined flint as the first “ore,” used (unaccountably, of course!) one of the main geochemical features of the element silicon, namely, its abundance: in the earth’s crust there is a little more than a quarter of silicon, t i.e. as much as all other elements combined (minus oxygen).
* (The most ancient stone tools, found in Kenya and Tanzania, were made more than 2.5 million years ago!)
True, in order to master such ore, it was necessary to study experimentally the basic properties of flint: the ability to produce a spark upon impact, high hardness, viscosity, and most importantly, a conchoidal fracture that forms a sharp cutting edge (Fig. 32).
In addition to the rational form and perfect processing of Stone Age tools, we are also struck by something else: Stone Age man (already in the Neolithic) did not limit himself to searching for first-class flints on the surface, he mined flint “ores” at depth. Neolithic underground flint mining is known in Belgium, France, England, Sweden, Poland and Belarus. One of the mines in Belgium (the town of Spienna) reaches a depth of seventeen meters. At the bottom of the mine there are horizontal workings, supported entirely by abandoned rock. One can only marvel at the skill with which Stone Age miners carved out these oldest mines on earth, precisely tracing layers of high-quality flint in the soft chalky limestone. These people cannot be denied involvement in mineralogy!
The first Neolithic city known in the history of mankind, Çatalhöyük in Southern Anatolia, which arose in the 7th millennium BC, is no less admirable. e. based on the "mining" industry. The area once occupied by this settlement was 32 acres! In this area there were houses with flat roofs, separated by narrow streets running up the hillside to the foot of the extinct volcanoes Karadzhidag and Gasandag. Archaeologist James Mellaart, who discovered it ancient settlement in 1958, describes the amazing things found there: bone and wooden vessels, figurines made of baked clay and dark green stone, including figurines of the Mother Goddess, small figures of people on foot and on horseback, images of bulls, rams, and leopards. Even more amazing are the bright multicolor paintings on the walls of the tomb temples and especially the huge, sometimes reaching two meters, bas-reliefs of people and animals. When making them, a layer of plaster was applied to a frame made of straw or clay, and to depict a deity with the head of a bull or cow, simply an authentic skull with horns was attached to the temple wall as the basis of a bas-relief, which was also then covered with painted plaster.
Archaeologists established the composition of the herd that belonged to this tribe and learned that, in addition to cattle breeding and agriculture, the people of Çatalhüyük hunted wild donkeys, deer, wild boars, and leopards. And yet, according to James Mellaart, the basis of their existence, which determined the entire way of life and the unprecedented size of the settlement at that time, was the extraction of obsidian - an excellent raw material for ceremonial and military weapons. Inexhaustible reserves of this high-quality raw material were hidden in the “pantries” of the Karadzhidag and Gasandag volcanoes. It can be considered that Çatalhöyük is one of the first settlements on earth of “monopolists” of excellent “strategic raw materials” of the Stone Age. The best samples Archaeologists found this ancient “ore” hidden in reserve under the floors of houses.
But another find is also interesting in Çatalhöyük: it was here that the most ancient * metal products - small awls, piercings, and beads - were first found. Research has shown that they are made primarily of copper.
* (Somewhat later, in the upper reaches of the river. The Tigris, east of Çatalhöyük, were discovered small items made of copper (VIII - VII millennium BC e.).)
Perhaps in Southern Anatolia people first became acquainted with ore in our understanding of the word. Archaeological finds show that mineralogists who lived almost nine thousand years ago were well aware of the properties of not only volcanic glass, but also some copper minerals.
So, the first acquaintance with ore took place back in the Stone Age, when people noticed that not all stones crack from the heat of a fire and fly into sharp fragments (stone processing often began with a fire); sometimes they come across blocks that become soft and pliable in the fire - malleable. For the first time, a person’s palm felt the magnificent heaviness and coolness of metal!
Probably, first of all, “ready” metals were mastered - native copper, gold, iron. They are both metals and minerals - natural formations permanent composition.
But what exactly made gold “the metal of kings and the king of metals”? Why was copper ahead of iron by almost five thousand years, and aluminum has been known to us for a little over a hundred years? Why do we call tantalum, beryllium and cesium “metals of today”?
It turns out that the fate of a metal very often depends not only on its own qualities, but also on the properties of its natural compounds - minerals. Let's remember the history of the development of metals.