Direct reduced iron b briquettes, lumps, pellets, coldmoulded. This paper attempts to postulate the kinetics and mechanisms of oxidation of dri. The starting point for the efforts to find an alternative to the blast furnace process was the relatively high process expenditure. However, the disadvantages inherent to the process led to the development of alternative processes such as the mini blast furnace process, smelting reduction process, and direct reduction process. Resources trend and use of direct reduced iron in steelmaking. Direct reduction plants produce different materials that are based on. Direct reduced iron has become a widely accepted source of premium iron units for steel making. Midrex the worlds leading directreduced iron production.
Direct reduced iron dri, also called sponge iron, is produced from direct reduction of iron ore in the form of lumps, pellets or fines by a reducing gas produced from natural gas or coal. Sponge iron production by direct reduction of iron oxide. Iron ore lump ore, pellets, or a mixture thereof is charged into the reduction shaft, where it is reduced to direct reduced iron dri by the reduction gas in counterflow. Direct reduction processes direct reduction is defined as a process of producing solid iron product. Sep 23, 2011 current state in iron production the worlds first commercial rhf, with a diameter of 16. Direct reduction refers to solidstate processes which reduce iron oxides to metallic iron at temperatures below the melting point of iron.
Process description with corex, all metallurgical work is carried out in two separate process reactors the reduction shaft and the melter gasifier. Metallization can be adjusted at will, typically around 94% and higher. Most gasbased direct reduction plants are part of integrated steel minimills, located adjacent to the electric arc furnace eaf. Direct reduction processes can be divided roughly into two categories. Direct reduced iron and its production processes ispatguru. There are two main technologies for direct reduction of iron, midrex and energiron or hyl which together are responsible for 80% of the production of direct reduced iron in the world. Directreduced iron process dri nippon steel engineering.
Brief history of iron production according to most historians, the first iron used by man was of. Nov 27, 2014 in the search for a pure, available iron source, steelmakers are focusing their attention on directly reduced iron dri. Direct reduced iron dri is a highquality metal product obtained from iron ore. Hbi is the product of reducing iron ore with natural gas. Dri direct reduced iron or hbi hot briquetted iron. The production of direct reduced iron dri, a basic raw material for making steel, is concentrated in a few countries in the middle east and latin america. Potential for co2 emissions reduction in midrex direct. Qaqc and process optimization for direct reduced iron.
The direct reduced iron unit has a capacity of 200,000 tons a year and was built in 1997. It is typically used in smaller scale steel mills to enhance the condition of the steel that is manufactured. Dri direct reduced iron dri is reduced iron pellet andor lump, which is cooled and discharged at low ambient temperatures. Steel production american iron and steel institute. Minnitt synopsis direct reduced iron dri, produced by the reaction between iron ore and reducing gasses, is used as a source of lowresidual iron, in addition to ferrous scrap and pig iron, in the production of steel. The kiln has been designed based on certain ld ratio, percentage degree of inclination, rpm etc. Your partner for contracting to commissioning direct reduced iron plants. Gasification and the midrex direct reduction process by. Processes that produce iron by reduction of iron ore in solid state below the melting point are generally classified as dr. This material is produced by the reaction of a low gangue iron ore with a hydrocarbonaceous substance. Metallization, reformed natural gas, residual elements, rotary kiln. S16 u a direct reduced iron dri production plant is a shaft reduction furnace to produce dri with large metal iron content by directly reducing iron ore or iron. Commercially, dri is generated in four different reactors. This book provides a fascinating study of the very important emerging field of direct reduction in which iron ore is directly reduced in the solidstate, using either natural gas or noncoking coal, to produce a highly metallised material, referred to as sponge iron or direct reduced iron.
Direct reduction dr is defined as any process in which metallic iron is produced by the reduction of iron ore at temperatures below the iron melting point. The term direct reduced iron, or dri, has a generic meaning which covers a number of products with a variety of properties and hazards. Direct reduced iron dri is a quality metallic product, produced from iron are, pellets etc. The direct reduction process uses pelletized iron ore or natural lump ore. Resources trend and use of direct reduced iron in steelmaking process dr. This intermediate product is subsequently melted in electric arc furnaces or induction furnaces. The volume of steel produced by the, now oldfashioned, blast furnace process is already very low and will continue to decline relative to the volume of steel produced by the electric arc process, for which dri is the raw material. Direct reduced iron industry in india problems and prospects. This forms the direct reduced iron dri which is typically composed of 90 to 94% iron. Optimization of the iron ore direct reduction process through. Midrex is a process by which iron ore pellets, lump iron ore or a combination of both is reduced in a vertical. Direct reduced iron dri is the product which is produced by the direct reduction of iron ore or other iron bearing materials in the solid state by using noncoking coal or natural gas. As the iron oxide descends through the furnace, the iron oxide is heated and reduced.
In a series of fluidizedbed reactors, fine iron ore is reduced to direct reduced iron, compacted hci and then transported to a melter. Understanding the different direct reduced iron products gard. Its advantages as a virgin iron product and diluent for impurities, introduced with scrap, are well documented. Process update direct reduction process using fines and. Use of direct reduced iron in electric arc furnace ispatguru. Total worlds dri output in 1998, 1999, 2000 and 2001 in % 2 figure 2. There has been a disturbing increase in the number of potential life threatening incidents involving the carriage of direct reduced iron dri. A key feature of the finex process is that iron production is carried out in two separate process steps. Stidies on process kinetics intensification of dri making and improvement in. The gangue material in sponge iron, originating from iron ore, namely, silica and alumina and the sulphur and phosphorous contents adversely affect the economics in subsequent steel making operation. Stidies on process kinetics intensification of dri making and improvement in prouct. Direct reduced iron dri international iron metallics.
Midrex is a process by which iron ore pellets, lump iron ore or a combination of both is reduced in a vertical shaftreduction furnace. Pdf state of the direct reduction and reduction smelting. Characteristics of reduced iron the midrex process produces direct reduced iron hereinafter referred to as dri. Processes that produce iron by reduction of iron ore in solid state below the. Direct reduced iron dri, also called sponge iron, is produced from the direct reduction of iron.
Understanding the different direct reduced iron products. The use of eafs has expanded and now accounts for nearly 23 of steel production in the united states. The hydrogen is produced by means of natural gas reforming, but hydrogen from sources other than a steam reformer, e. The increasing role of direct reduced iron in global steelmaking. Aist is recognized as a global leader in networking, education and sustainability programs for advancing iron and steel technology. Hot direct reduced iron hdri is dri that is transported hot, directly from the reduction furnace, into an electric arc furnace, thereby saving energy. The reduced material then flows through catalyst tubes where it is chemically. In the search for a pure, available iron source, steelmakers are focusing their attention on directly reduced iron dri. Process update direct reduction process using fines and with reduced co2 emission a. The midrex process the worlds most reliable and productive direct reduction ironmaking technology. Direct reduced iron dri is the product of the direct reduction of iron ore in the solid state by carbon monoxide and hydrogen derived from natural gas or coal. Direct reduction processes are an alternative to the traditional blast furnace because of the use of h2 in the reducing gases which generate less co2.
Direct reduced iron dri production plant nippon steel engineering co. The increasing role of direct reduced iron in global. The properties of direct reduced iron, past experience with storage, shipment, and handling of midrexr iron, a direct reduced iron material produced in the. To focus on the emerging market and technological trends for the production, handling and use of dri and hbi products as well as present and future alternative iron production technology. Cost effectiveness analysis of hyl and midrex dri technologies for the iron and steelmaking industry by. The presentation describes different processes for the production of direct reduced iron. State of direct reduction and reduction smelting processes j. Many of these alternative processes are still under development. Circored is a two stage fluidized bed process, reducing iron ore fines directly without prior agglomeration, that operates at low reduction temperatures using pure hydrogen as the reducing gas. The midrex direct reduction process is the worlds leading technology for production of dri products dri products are orebased metallic raw materials made by removing chemicallybound oxygen from iron oxide pellets and lump ores without melting. Direct reduced iron industry in india problems and prospects t.
Directreduced iron an overview sciencedirect topics. Basic concept or summary s16 u a direct reduced iron dri production plant is a shaft reduction furnace to produce dri with large metal iron content by directly reducing iron ore or iron ore pellets with reducing gases. This product is known as direct reduced iron dri or sponge iron. Direct reduction process an overview sciencedirect topics. Future significant improvements will need either new melting technologies or faster power input capabilities. The major consumers of dri are the smaller steel mills which use dri to dilute the residual elements present in the steel. Nov 05, 2015 midrex is an innovative ironmaking process, developed for the production of direct reduced iron dri from iron ores and primarily natural gas. Rob cheeley senior sales engineer, midrex direct reduction corporation introduction the production of direct reduced iron dri, a basic raw material for making steel, is concentrated in a few countries in the middle east and latin america. The dri is used mainly as the raw material for electric arc furnaces eafs, as a clean iron source substitute for scrap iron.
The process reduces iron ore using a reforming gas made from natural gas. The reduction process takes place in the reduction tower. The blast furnace process is still the predominant method for primary iron production. The eaf is different from the blast furnace as it produces steel by using an electrical current to melt scrap steel andor direct reduced iron. Therefore, the ore should be high in iron content and low in gangue, physical specification. The process characteristics allow for independent control of the dri metallization and carbon levels. Brochure hbi hot briquettin g of direct reduced iron. Current state in iron production the worlds first commercial rhf, with a diameter of 16. Hotbriquetted iron hbi is a compacted form of dri designed for ease of shipping, handling and storage. State of direct reduction and reduction smelting processes. During the reduction process in the production of direct reduced iron, either coal or a special gas commonly containing a combination of. Midrex direct reduced iron cooling gas scrubber cooling gas compressor iron oxide natural gas is used as a reductant. Properties and features of direct reduced iron request pdf.
Despite the fact that the reoxidation of direct reduced iron dri has created wellknown problems for industry involving storage, shipping, and handling of this material, surprisingly very little information on this subject has been reported in the literature. Directreduced iron dri, also called sponge iron, is produced from direct reduction of iron ore in the form of lumps, pellets or fines by a reducing gas produced from natural gas or coal. Aftermarket group dedicated to continual support of your midrex plant. The midrex process is a shafttype direct reduction process where iron ore pellets, lump iron ore or a combination are reduced in a vertical shaft reduction furnace to metallic iron by means of a reduction gas see figure 1. Total worlds dri output by processes in 2001 in % 2 3. Consequently, the interest in dr processes began to decrease. Analysis of dri can vary based on the source and composition of iron ore used for making dri, the process of making dri and the process control practiced at the time of making dri. Process update direct reduction process using fines and with. In both cases, the objective of the process is to drive off the oxygen contained in various forms of iron ore sized ore, concentrates, pellets, mill scale, furnace dust, etc. Production of direct reduced iron in rotary hearth furnace. Direct reduced iron dri the world market for steel is expected to continue to increase. Pelletslump ore are reduced to produce dri without being melt in the shaft furnace. Metallization, reformed natural gas, residual elements, rotary kiln, direct reduced iron and its production processes.
Direct reduced iron dri is technically defined as iron ore which has been reduced to metal without melting it. The direct reduction dr process is one such ironmaking process that can substitute for blastfurnace bf ironmaking. Hot briquetted iron hbi is a densified form of dri to facilitate its handling and transport. Directreduced iron is also known as sponge iron and is sold as briquettes, lumps, or pellets. Directly reduced iron is a product of iron steel direct reduction from ores in the solid state at a temperature lower than the melting point and without coke dri tn. Since the early 1900s, however, the electric arc furnace eaf emerged, using steel scrap as the. The reducing gas is a mixture majority of hydrogen h2 and carbon monoxide co which acts as reducing agent. This is called the direct reduction process and is an environmentallyfriendly production process. Iron ore direct reduction is an attractive alternative steelmaking process in the context of greenhouse gas mitigation. Because, during hot briquetting, the large specific surface area of direct reduced iron. Midrex is an innovative ironmaking process, developed for the production of directreduced iron dri from iron ores and primarily natural gas. Dri is available in the composition ranges as given below. Direct reduced iron and production of dri part 2 youtube.
The kinetics and mechanisms of oxidation of direct. Mar 11, 2016 the presentation describes different processes for the production of direct reduced iron. The product of a dr process is called direct reduced iron dri. In addition to the process route via the blast furnace process, there is another option for extracting crude steel from iron ores using the socalled direct reduced iron dri process secondary route. Dri and its derivatives, including hot briquetted iron hbi, are a virgin iron feedstock that is often used in steelmaking.
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