In the basic oxygen furnace, the iron is combined with varying amounts of steel scrap less than 30% and small amounts of flux. Introduction of high quality coke to a blast furnace will. How pig iron is converted into iron and steel in blast. The bottom cylindrical part of the profile is called a hearth, wherein pig iron and slag. Steelmaking process an overview sciencedirect topics. At sufficiently high temperatures, the carbon can participate directly in the. Iron ores with lower iron content such as taconite are first processed to concentrate the iron level and drive off volatile impurities. Early processes of steel making were made during the classical era in science and technology in india, china, iran, and rome but the process of ancient steelmaking was lost in the west after the fall of the western roman empire in the 5th century ce. The following text is taken from the structural manual for ironworkers manual vvolume i. This module introduces the learner to the operation of the blast furnace for the transformation of iron ore to molten iron. The iron in the processed ores must be dissolved out by chemical processes. The raw materials require 6 to 8 hours to descend to the bottom of the furnace where they become the final product of liquid slag and liquid iron. The metal in the ladle is sent directly for basic oxygen steelmaking or to a pretreatment stage.
This requires an element that binds oxygen more strongly than iron. Iron is made by reacting iron ore iron oxide and impurities, coke a reductant and limestone caco 3 in a blast furnace. Co steel raritan inland lukens ameri steel caparo steel figure 2. Basics of blast furnace introduction to blast furnace. Blast furnace training dvd from the bcsa and tata steel. Steelmaking has played a crucial role in the development of ancient, medieval, and modern technological societies. Ironmaking, the first step in making steel, involves the raw inputs of iron ore, coke, and lime being melted in a blast furnace. Scrap is charged to the furnace through doors in the furnace front. The carbon is fed to the blast furnace in the form of coke pyrolyzed coal from the coking plant. Process analysis for blast furnaces by the discrete.
Blast furnace gas cleaning plant nippon steel engineering. The basic oxygen steelmaking process is as follows. The principle of blast furnace operational technology and. For this reason, many steel plants desulfurize blastfurnace iron before it is refined into steel, since at that stage it contains practically no dissolved oxygen, owing to its high silicon and carbon content. 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. Introduction kobe steel started operation as an integrated steel manufacturing company with the blowingin of the no.
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. A blast furnace is a type of metallurgical furnace used for smelting to produce industrial metals, generally pig iron, but also others such as lead or copper. Modern steel making process uses a blast furnace for manufacturing steel. Presentation at edrc kolkata on 14th feb 2007 by n. The figure shows a flowchart of the integrated manufacturing process for iron and steel using the blast furnace and basic. A lance is introduced in the vessel and blows 99% pure oxygen causing a. Blast furnace basic oxygen furnace uses iron ore as its base raw material that accounts over just 50% of bof steel costs, and electric arc furnace uses scrap as its base that represents around 75% of eaf steel cost. Blast furnace gas has a high carbon monoxide co content and a low heating value, typical. In the electric arc furnace route eaf 100% scrap used. Liquid iron hot metal is produced in a blast furnace from the burden materials through a series of chemical reactions which are taking place at various levels in a blast furnace. Chemistry of the ironmaking by blast furnace process. The development of direct reduction plants dr plants represents a key change in steel production. Energysaving blast furnace nippon steel engineering co.
Profile of a blast furnace and its dimensions are adapted to technology of process, see figure. Cognizant that the raw materials used in iron making are granular bodies, tanaka et al. Electric arc furnace steelmaking continuous casting. The demands with regard to the resources, and necessary pre. Pdf ironsteel making from start to finish researchgate. The production of iron in a blast furnace is a continuous process. Iron ore processing for the blast furnace courtesy of the national steel pellet company the following describes operations at the national steel pellet company, an iron ore mining and processing facility located on the mesabi iron range of minnesota. It can be seen that blast furnace bof steelmaking route consumes 19. Compared to this, elsewhere furnaces up to 5070 m 3 had. The process of stopping the blast furnace operation at the end of its campaign is known as. The furnace is heated constantly and is recharged with raw materials from the top while it is being tapped from the bottom.
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. Iron ore, as mined, is a combination of iron with oxygen and various other unwanted substances, generally known as gangue. The electric furnace steelmaking dust is formed at melting metalized pellets in electricarc steel making furnaces and is a largetonnage waste. Salzgitter the process shown above is illustrative only and is not designed to show the steelmaking process in detail. Larger blast furnace, use of better prepared burden, recovery of waste energy, and maximum recovery of slag characterize the iron making technology proposed for vsp. Hot metal from the blast furnace is added by pouring from a ladle through a trough. To make steel, iron ore is first mined from the ground. 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. Blast furnaces are used to produce pig iron from iron ore for subsequent processing into steel. The decarburization process is an important source of energy. Direct reduction scrap ladle refining electric arc furnace steelmaking iron ore pellets.
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. Creating steel from lowgrade iron ore requires a long process of mining, crushing. Plant and equipment, metallurgical processes, chemistry, raw materials, products and byproducts, operation, alternative. 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. The resulting molten ironalso referred to as hot metalstill contains 44. Blast refers to the combustion air being forced or supplied above atmospheric pressure in a blast furnace, fuel, ores, and flux are continuously supplied through the top of the furnace, while a hot blast of air sometimes with. 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.
Molten pig iron sometimes referred to as hot metal from a blast furnace is poured into a large refractorylined container called a ladle. In fact, a very simple definition of steel is iron alloyed with carbon, usually less than 1%. 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. Ironmaking 101 from ore to iron with blast furnaces. This is the remelting of steel without the use of primary raw materials.
The process is continuous with raw materials being regularly charged to the. Even though converting the blast furnaces to hydrogen is an important first step, a fundamental transformation of steel production is required. It is then smelted in blast furnaces where the impurities are removed and carbon is added. A typical blast furnace along with its various parts is shown in fig.
The basic oxygen steelmaking process differs from the eaf is that bof is selfsufficient in energy. Blowing in blowing out black draughting banking discuss here. The blast furnace module is part of the steel manufacturing course. This is exactly what carbon can do as a reducing agent. Santanu chakraborty, in treatise on process metallurgy. In the blast furnaces bf liquid iron popularly termed as hot metal is produced by the process of reduction at high temperature from raw materials like iron ore, base mix, sinter, pellet, coke, fluxes limestone, quartzite, dolomite. Iron making in the furnace usually continues for about ten years before the furnace linings have to be renewed. A low iron oxide content is also essential, since oxygen and sulfur compete to combine with the calcium. The iron from the blast furnace is then further refined and converted to steel in the basic oxygen furnace bof. Creating steel from lowgrade iron ore requires a long process of mining, crushing, separating, concentrating, mixing, pelletizing, and shipping. Which one of the following process of steel making is also known as thomas process. This special issue, ironmaking and steelmaking, released by the journal metals is. Depending on the plant, 2030% of scrap is added to this process, primarily to regulate the temperature. Steel production basics steel is produced using primary or secondary methods, as shown in figure 2.
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