Corex Process for Production of Iron Feb22

Corex Process for Production of Iron...

Corex Process for Production of Iron During the late twentieth century, several new initiatives have been taken for the development of the smelting reduction technology which can become alternative route for the production of liquid iron (hot metal) since the conventional blast furnace (BF) ironmaking depends on metallurgical coal, which is required for producing BF coke needed for the production of hot metal in the blast furnace. Metallurgical coal is not only costly but is associated with environmental issues during its conversion to BF coke in the coke oven batteries. Smelting reduction process is that process which is based on smelting reduction technology and hence in this process the production of hot metal is carried out without the use of metallurgical coke. Corex process is one of these initiatives. It is the first and the only commercially established smelting-reduction process based on non-coking coal which is available as an alternative route to the blast furnace for the production of hot metal. Corex process was developed by the Austrian technology supplier VOEST in the late 1970s, and its feasibility was confirmed during the 1980s. The first pilot plant was installed in Kehl, Germany, in 1981. Commercialization, however, was reached together with the South African steelmaker ISCOR where the C-1000 (C – 0.5 M) module was commissioned in November 1989 at its Pretoria works. This first generation reactor which is called melter-gasifier had a hearth diameter of 5.5 m and a hot metal production rate ranging from 40 tons per hour to 60 tons per hour. The plant rated capacity was 300,000 metric tons per year. The general applicability of this first generation process was limited and a lot of technical problems had to be solved. Nevertheless, it helped to overcome the critical demonstration stage for...

Coal based Direct Reduction Rotary Kiln Process Feb14

Coal based Direct Reduction Rotary Kiln Process...

Coal based Direct Reduction Rotary Kiln Process The coal based direct reduction rotary kiln process was developed for converting iron ore directly into metallic iron without the melting of the materials. The process has the advantage of low capital expenditure and no requirement of coking coal. The metallic iron in this process is produced by the reduction of iron oxide below the fusion temperature of iron ore (1535 deg C) by utilizing carbonaceous material present in the non-coking coal. As the iron ore is in direct contact with the reducing agent throughout the reduction process, it is often termed as direct reduced iron (DRI). The reduced product having high degree of metallization shows a ‘honeycomb structure’, due to which it is often called sponge iron. Coal based DRI plants are flexible with respect to plant location since non-coking coal is widely distributed in large deposits and is easy to transport. Most plants employ reduction process which is carried out in rotary kilns. These plants use wide variety of raw materials and non-coking coal. The quality of these materials has direct bearing on the process as well as the product. Some plants do not use iron ore directly. These plants use iron ore pellets in the rotary kiln. Raw material mix consisting of iron ore, dolomite and non-coking coal is fed at the one end of the rotary kiln and is heated by coal burners to produce DRI. The product DRI along with char (sometimes called dolo char) is taken out from the other end of the kiln. Apart from this, primary air and secondary air are supplied to the kiln to initiate the combustion and sustain the reaction process in the kiln. Raw materials The main raw materials for the production of DRI by...

Understanding Pellets and Pellet Plant Operations Mar21

Understanding Pellets and Pellet Plant Operations...

Understanding Pellets and Pellet Plant Operations Pelletizing is an agglomeration process which converts very fine grained iron ore into balls of a certain diameter range (normally 8mm to 20 mm, also known as pellets. These pellets are suitable for blast furnace and direct reduction processes. Pelletizing differs from sintering in that a green unbaked pellet or ball is formed and then hardened by heating. Iron ore pellets  can be made from beneficiated or run of mine iron ore fines. Lean iron ores are normally upgraded to a higher iron ore content through beneficiation.  This process generates iron ore filter cake which needs to be pelletized so that it can be used in an iron making process.  Also during the processing of high grade iron ores which do not need beneficiation, generated fines can be pelletized and used instead of being disposed of. Pellet plants can be located at mines, near ports or can be attached to steel plants. Equipped with advanced environmental technology, they are virtually pollution free, generating no solid or liquid residues. History of pelletization The history of pellets began in 1912 when A.G.Andersson, a Swede, invented a pelletizing method. The commercial use of pellets, however, began in the USA after World War. Various studies were conducted in USA with the aim of developing the vast reserves of taconite (a low grade iron ore) in the area around the Great Lakes. The process of enriching taconite ore involved grinding the ore to remove gangues and upgrading the iron ore (i.e., an ore beneficiation process). The resultant high grade ore is in the form of fine particles, as small as 0.1 mm or less, which are not suitable for sintering. This issue led to the development of the pelletizing process. In 1943, Dr. Davis,...

Iron ore pellets

Iron ore pellets Iron ore pellet is a type of agglomerated iron ore fines which has better tumbler index when compared with that of parent iron ore and can be used as a substitute of lump ore for the production of direct reduced iron (DRI) and in blast furnaces for the production of hot metal. The term iron ore pellets refers to the thermally agglomerated substance formed by heating a variable mixture of iron ore, limestone, olivine, bentonite, dolomite and miscellaneous iron bearing materials in the range of 1250 deg C to 1350 deg C. Iron ore pellets are normally produced in two types of grades namely DRI grade and BF grade. BF grade pellets have higher basicity than the DRI grade. The general identification details of iron ore pellets are given Tab 1. Tab 1 Identification details of Iron ore pellets Chemical name Iron ores, agglomerates Other names Iron ore pellets, iron oxide pellets CAS No. 65996-65-8 EINECS No. 265-996-3 Molecular formula Fe2O3 Molecular weight (gram/mole) 159.7 Synonyms Di iron trioxide Mineral of identical or similar composition Hematite Other identity code: Related CAS No. Hematite (Fe2O3) 1317-60-8 REACH (Registration, Evaluation, Authorization, and restriction of Chemicals) registration No. 01- 2119474335-36-0013 DRI pellets donot contain CaO while BF grade pellets are fluxing pellets containing CaO. For BF grade pellets reducibility and swelling index are important properties while for DRI grade disintegration is an important property. The properties of pallets are given in Tab 2. Tab 2 Properties of pellets Size 8-20 mm Appearance Granular Colour Dark grey Odour Odourless pH (40 gm/L,20Deg C; slurry in water) 5.0 – 8.0 Melting point 1500-1600 deg C Bulk density 2.0 -2.2 t/Cum Water solubility Insoluble Oil solubility Insoluble Tumbler index (+6.3 mm) 93-94 % Abrasion index (-0.5 mm) 5-6...