Iron is made by reacting iron ore iron oxide and impurities, coke a reductant and limestone caco 3 in a blast furnace iron ores with lower iron content such as taconite are first processed to concentrate the iron level and drive off volatile impurities. Blast furnace, midrex direct reduction iron dri, corex. Pdf optimization of lump ore proportions in blast furnace. Coke is cheap and provides both the reducing agent for the reaction and also the heat source. How pig iron is converted into iron and steel in blast. Feature 1 kobe steels blast furnace operation technology. A relatively large percentage of hightemperature gases flow through the thin.
General flow diagram for the iron and steel industry. The first metallurgical step is to reduce iron ore to metallic iron, a process which is mostly carried out in a blast furnace, using coke as both a fuel and reducing agent. The iron ore concentrate is now mixed and ready for the pelletizing process. Calculation of blast furnace size is empirical in nature. The term allpellet operation means that all the processed iron ore has been turned into iron ore pellets. In his discussion of electricfurnace production of pig iron and pig steel before the engineers society of western pennsylvania, dr. A blast furnace charge consists of ore, fluxes and fuel. The underlying emphasis of new technologies is to maximize the low grade iron ore in the blast furnace eliminating the use of high grade iron ore which are depleting faster. As the mixture of iron ore, coke and limestone heats, the hot waste gases are collected and cleansed. Blast furnace and process description chemical engineering. The burden charge consisting of iron oxide, flux and coke and it provides through the throat from the top of the furnace. The blast furnace is a huge, steel stack lined with refractory brick, where iron ore, coke and limestone are dumped into the top, and preheated air is blown into the bottom. Carburization behavior of molten iron in blast furnace is an essential part of bf long campaign technology.
The iron is reduced from the ore by carbon in the coke, the limestone aiding slag separation from the molten iron. Operational observations, challenges and remedies are explained from this perspective. Iron ores such as haematite contain ironiii oxide, fe2o3. Coke, limestone flux, and iron ore iron oxide are charged into the top of. The most common ore of iron is called haematite iron iii oxide. Of the raw material used in blast furnaces, iron ore that has gone through a prefiring process, such as iron ore pellets and sintered ore, is called processed iron ore.
This book describes the blast furnace process for operators. This page looks at the use of the blast furnace in the extraction of iron from iron ore, and the conversion of the raw iron from the furnace into various kinds of steel. Extraction of iron metallurgy blast furnace and reactions. A blast furnace is usually built with a steel case and bricks made of.
Iron ore agglomeration processes and their historical. Process of blast furnace pdf a blast furnace is a huge steel container many metres high and lined. Blast furnace gas has a high carbon monoxide co content and a low heating value, typical. Blasts furnaces are used for smelting during the production of metals such as iron, lead, zinc, and copper. Cn1743476a nickeliron smelting process from nickel. The large, refractory lined furnace is charged through its top with iron as ore, pellets, andor sinter. Iron processing, use of a smelting process to turn the ore into a form from which products can be fashioned. The reducing gas from 1020% co and 8090% h2 is produced from natural gas. Fine ore injection into blast furnace through tuyeres.
The oxygen must be removed from the ironiii oxide in order. In this model it is assumed that the liquid phase formed will move together with the remaining solid phase due to the viscosity, thus, equations for momentum transfer and. Blast furnace iron making is the main method for modern steel production,the process of blast furnace is an important part. Extracting iron from iron ore using a blast furnace. Trends in ironmaking given the new reality of iron ore and coal resources. They are then used to help heat the air blast, required if blast furnace is to reach the high temperatures needed to produce molten iron. It is in the blast furnace that extraction of iron occurs. Advantages of fine ore injection through tuyeres in large quantities injecting fine iron ore or pulverized coal into a blast furnace through tuyeres in large quantities brings about the following advantages compared with conventional blast furnace operating. A typical blast furnace along with its various parts is shown in fig. The most common ore of iron is called haematite ironiii oxide. Extraction of iron in a blast furnace iron is also below carbon in the reactivity series, so therefore carbon can be used to reduce it note. Pdf the coke and iron ore materials kinetic characteristics and. Pdf technological tendencies of blast furnace practice and.
At sufficiently high temperatures, the carbon can participate directly in the. The blast furnace process can be briefly described as follows. A blast furnace works by blasting hot air up through the furnace while fuels, limestone, and ore move continuously through the top of the furnace. The blast furnace process for the manufacture of iron has been in. Heavy industrial mining equipment, expansive mines, and a skilled labor pool.
Iron blast furnace is a vertical shaft, which is used to melt the iron ore and to produce hot metal by heat exchange and chemical reaction. Blast furnace process an overview sciencedirect topics. Iron ore, as mined, is a combination of iron with oxygen and various other unwanted substances, generally known as gangue. Iron is extracted from iron ore in a huge container called a blast furnace. This concentrated ore is mixed with limestone caco 3 and coke and fed into the blast furnace from the top. The first metallurgical step is to reduce iron ore to metallic iron, a process which is mostly carried out in a blast furnace, using coke as both a fuel and reducing. Pdf the most important problem at the blast furnace process developing is the great coke consumption decreasing at the minimization of the general. The carbon \c\ is oxidized to carbon monoxide \co\ by the absorption of oxygen \o\. The blast furnace process has auxiliary equipment associated with it. This is exactly what carbon can do as a reducing agent. Iron ore is usually a mixture of iron and vast quantities of impurities such as sand and clay referred to as gangue. Nippon steel has come to an agreement with mitsui o. Blast furnaces are used continuously and are only shut down when their brick lining needs replacing. Consequently, rich iron ore andor iron oxide pellets formed from concentrate can be added directly to.
This requires an element that binds oxygen more strongly than iron. Blast furnace produces hot metal liquid iron using iron ore, coke, sinter. The blast furnace is a countercurrent gassolids reactor in which the descending column of burden materials coke, iron ore and fluxesadditives reacts with the ascending hot gases. Iron fe is a relatively dense metal with a silvery white appearance and distinctive magnetic properties.
Maintaining carbon content stable is an important prerequisite to ensure the high. The blast furnace process for the manufacture of iron has been in existence. Kobe steel has developed a coal based dr process which utilizes. Blast furnace gas is produced during the iron oxide reduction in blast furnace iron making in which iron ore, coke and limestone are heated and melted in a blast furnace and is an indigenous process gas of the steelworks industry pugh et al. The process is continuous with raw materials being regularly charged to the top of the furnace and molten iron and slag being tapped from the bottom of the. Download pdf blastfurnaceironmaking free online new. The blast furnace operates as a countercurrent exchange process whereas a bloomery does. This ore is either hematite fe 2 o 3 or magnetite fe 3 o 4 and the iron content ranges from 50% to 70%. The iron found in iron ores are found in the form of iron oxides. Iron fe is a relatively dense metal with a silvery white appearance and distinctive.
Blast furnaces produce pig iron from iron ore by the reducing action of carbon supplied as coke at a high temperature in the presence of a fluxing agent such as limestone. Depending on the ore used and the reaction conditions temperature, air supply, additives, the resulting reaction product is a mixture of different proportions of slag, partially reduced iron ore. State of direct reduction and reduction smelting processes j. As a starting point, the blast furnace is seen as a simple iron ore melter, while gradually the physical, chemical and metallurgical background is clarified. The common ores of iron are both iron oxides, and these can be reduced to iron by heating them with carbon in the form of coke. Blast furnaces are also called high ovens a blast furnace is usually built with a steel case and bricks made of magnesium oxide or other refractory material inside. Consequently, rich iron ore andor iron oxide pellets formed from concentrate can be added directly to a blast furnace see iron production.
The iron making blast furnace itself is built in the form of a tall chimneylike structure lined with refractory brick. Included in this article also is a discussion of the mining of iron and of its preparation for smelting. Despite the challenges, blast furnace ironmaking shall continue as the main source of highquality hot metal. This also makes it possible to maintain the quality of iron ore used for sinter and improves the properties of sinter. Improper working of the furnace due to frequent disturbance in gas flow pattern. Iron ore, limestone and coke is the stock of the blast furnace. The ore is loaded into a blast furnace along with measured quantities of coke and limestone. The softening and melting of blast furnace burden materials. Coke is produced by heating coal in the absence of air.
Blast furnace products and there use size of blast furnace design of blast furnace is evolved through experience. A blast furnace is a special type of furnace for smelting iron from ore. The sintering process converts finesized raw materials, including iron ore, coke breeze. Blast furnace simple english wikipedia, the free encyclopedia. May 22, 2009 the step by step process of extracting iron from its ore using the blast furnace with details of chemical reactions. The process of mining lowgrade iron ore, or taconite, requires massive resources.
Jul 12, 2019 blast furnace and process description. Overview of the steelmaking process pellets sinter limestone coke iron ore coal scrap blast furnace ironmaking converter steelmaking ladle refining blast furnace steelmaking coalnatural gas plate hotrolled bars rods tube rounds rails slab billet bloom hotrolled and coldrolled strip coils structural shapes. The development of new iron making processes, kobelco. This removal can take place either above or below the melting point of the ore and the. By means of prereduction of iron ore fines, productivity of a blast furnace can be increased and iron ore unsuitable for sintering process can be easily used in the blast furnace.
The step by step process of extracting iron from its ore using the blast furnace with details of chemical reactions. They can be up to 60 metres 200 ft tall and 15 metres 49 ft in diameter. The raw ore is removed from the earth and sized into pieces that range from 0. The blast furnace process is primarily used in the carbothermic reduction of oxides, such as iron, zinc, and lead. Aug 04, 2011 iron oxides can come to the blast furnace plant in the form of raw ore, pellets or sinter. Ironmaking blast furnaces consist of several zones. The production of iron from its ore involves an oxidationreduction reaction carried out in a blast furnace.
How a blast furnace works introduction the purpose of a blast furnace is to chemically reduce and physically convert iron oxides into liquid iron called hot metal. In the basic oxygen process bop, molten iron from a blast furnace and iron scrap are refined. The sinter with iron ore fines mean particle size 2. Once a blast furnace is started it will continuously run for four to ten years with only short stops to perform planned maintenance.
A variety of processes take place within the blast furnace, as the stock slowly moves downwards and temperatures increase. Us2373244a us499235a us49923543a us2373244a us 2373244 a us2373244 a us 2373244a us 499235 a us499235 a us 499235a us 49923543 a us49923543 a us 49923543a us 2373244 a us2373244 a us 2373244a authority us united states prior art keywords blast furnace iron charging flue dust mixture prior art date 19430819 legal status the legal status is an assumption and is not a. Hot combustion air is supplied to the furnace and some form of fuel used to raise the temperature. Blast furnace, a vertical shaft furnace that produces liquid metals by the reaction of a flow of air introduced under pressure into the bottom of the furnace with a mixture of metallic ore, coke, and flux fed into the top. Blast furnace ironmaking process using prereduced iron. After mining, various kinds of iron ores are brought to the blast furnace which is the starting process for refining iron ores or mined ores and for the production of pig iron. It constitutes 5 percent by weight of the earths crust, and it is the. This auxiliary equipment and the gaseous pathways inside a blast furnace process are shown in fig. Although there are various iron making processes, the mini blast furnace route is the most preferred.
This book discusses the importance of blastfurnace process as a complete operation. Most of the iron ore bodies commercially explored consist of iron oxides. Pelletizing a pellet plant contains a series of balling drums where the iron ore concentrate is formed into soft pellets, in much the same manner that one rolls a snowball, to make a pellet about the size of a marble between 14 and 12. The ore part of a charge consists of iron ores and concentrates, manganese ores and various types of scrap containing iron.
May 03, 2010 the iron making blast furnace itself is built in the form of a tall chimneylike structure lined with refractory brick. The iron in the processed ores must be dissolved out by chemical processes. Energy flow and process gas utilisation in integrated steelworks. Question answers based on the process of extraction of metals. If the iron ores, which have not yet been reduced, move further down in the blast furnace, then the carbon can also directly reduce the iron oxides contained in the ore due to the high temperatures. Theory and practice presents the significant role of iron blast furnace by which iron is efficiently and rapidly reduced from ore and it is the basis for all primary steelmaking. The reaction processes of blast furnaces resemble the functions of the.
Iron ore mining in goa is completely in the private sector. A containing water of crystallization by the blast furnace smelting nickel oxide ore nickeliron process, wherein. Combining two decisive advantages leads to lower production costs and essential reduction of environmental emissions in comparison with the conventional blast furnace route. Now there are nearly 700 blast furnace available in world.
Extraction of iron in a blast furnace reduction haematite o. Blast furnaces are used to produce pig iron from iron ore for subsequent. The extraction of iron from its ore is a long and subdued process, that helps in separating the useful components from the waste materials such as slag. Iron oxides, flux agents, and metallurgical coke are added to a skip car at the stock house. The slag and molten iron are tapped off from the bottom of the furnace, the slag being. Ironmaking 101 from ore to iron with blast furnaces. The carbon is fed to the blast furnace in the form of coke pyrolyzed coal from the coking plant.
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