الفهرس 
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Abstract
The objective of this report is to a brief study of different method of iron production and attaching importance to production of iron by direct reduction processes and characteristic of spongy iron (DRI) and deal with MIDREX process as a case study. Pure iron is not readily available since it easily oxides in the presence of air and moisture. The iron industry reduces iron oxides to obtain pure iron, the basic materials for iron production are iron ore, coal and coke (also used as energy input to the process) or alternative reducing agents (synthetic gases H2 and CO). Blast furnace is a process for producing liquid raw iron by smelting pellets or sinter in a reducing environment. The end products are usually molten metal, slag and blast furnace gas. In the reduction process, oxygen (O2) is taken out of the pellets or sinter. Coke is often used as a reducing agent, as well as fuel. Fuel (coke) and pellets or sinter are supplied continuously through the top of the furnace and O2- enriched air is blown out the bottom by electrical air ventilators. The chemical reactions take place while the materials move downward. Coke also serves as a carrier to move the bulk material column downward in the blast furnace. The fuel and reducing agent, the content of the furnace needs to have optimum permeability to the flow of gaseous and molten products. The lower heating value of blast furnace gas ranges from approximately 2.7 to 4.0 MJ/Nm3. The production of blast furnace gas is approximately 1200 to 2000 Nm3/t pig iron. Much effort is devoted to increasing efficiency and reducing emissions of the blast furnaces. Direct reduction is the name of a broad group of processes based on different feed stocks, furnaces, reducing agents, etc. The common principle is the removal of oxygen (reduction) from iron ores in the solid state. Natural gas and in some cases coal is used as a reducing agent to enable this process. In 2000, some 92.6% of DRI was based on natural gas processed in shaft furnaces, retorts and fluidized bed reactors. The metallization rate of the end product ranges from 85% to 95 % (often even higher). DRI is prone to combustion and is therefore sometimes called hot briquetted iron (HBI). The concept of direct reduction dates from the 1950s, with the first plant operated in 1952. DRI production has been steadily growing since 1970, with a fallback in 2008 and 2009 due to the ongoing financial crisis. In 2008, the global DRI production amounted to 68.5 Mt and was based primarily on MIDREX technology (58.2%), on HYL/Energy iron (14.5%), and on other gas based (1.6%) and coal-based (25.7%) technologies. Gojic and Kozuh have identified 30 different DRI processes of which MIDREX is the world’s leading technology. The MIDREX process often consists of four stages: 1) Reduction gas, 2) Reform NG, 3) Heat recovery and 4) Briquette making. A mixture of pellets or lump ore, possibly including up to 10% of fine ore, enters the furnace shaft. As ore descends, oxygen is removed by counter-flowing reduction gas, which is enriched in hydrogen and carbon monoxide. In total, some 166 DRI facilities were in operation in 2008.