Redsmelt process for ironmaking Apr19

Redsmelt process for ironmaking...

Redsmelt process for ironmaking Redsmelt is a new ironmaking process based a two reduction steps. These are (i) pre-reduction of iron bearing materials in a rotary hearth furnace (RHF), and (ii) smelting of the hot pre-reduced iron (DRI, direct reduced iron). Originally a submerged arc furnace (SAF) has been used for the second step. SAF has now been replaced by a coal and oxygen blown converter (oxy-coal reactor) known as ‘New Smelting Technology’ (NST). The RHF reduces green pellets made out of iron ore, reductant fines and binders to produce hot, metallized DRI which is charged to the NST for its smelting to hot metal. Redsmelt process has been conceived to be consisting of a cost-effective and environmental-friendly technology. The important highlights of the process are as follows. The process does not need any prepared charge materials The process does not need electrical energy, since the DRI smelting is carried out using chemical energy The smelter is having high productivity resulting into limited investment cost The process can use practically all the residues generated during various processes of the steel plant (including sludges and oily mill scales), thus it solves the increasing issue of steel wastes treatment The off-gas coming from the smelting reactor is used as a fuel in the RHF, with optimization of the overall energy utilization. This results into effective reduction in energy consumption A Redsmelt demonstration plant with two step smelting reduction process was built and tested in Piombino works (Italy) for the production of hot metal. The demonstration plant was commissioned in the year 2003. The two production steps in the demonstration plant have been based upon pre-reduction of iron-bearing materials in a RHF and smelting of the hot DRI in an oxy-coal converter. The plant has been designed...

Process for Manufacturing of Iron Carbide Mar11

Process for Manufacturing of Iron Carbide...

Process for Manufacturing of Iron Carbide Iron carbide (Fe3C) is a high melting point, non-pyrophoric, strongly magnetic synthetic compound obtained in granular form. It consists of around 90 % total iron (Fe) and around 7 % total carbon (C). The primary use of the product is as a metallic charge during steelmaking for substitution of hot metal (HM), direct reduced iron (DRI), or steel scrap. The iron carbide process involves conversion of preheated fine iron ore particles to iron carbide. It reduces iron ore to iron carbide in a fluidized bed reactor, by contacting the iron ore with process gas consisting primarily of methane (CH4) and hydrogen (H2). The process for the manufacturing iron carbide was originally designed and developed at Hazen Research Inc. in Golden, Colorado, USA by the technical vice president Dr. Frank M. Stephens. The process involves reduction of preheated fine iron ore particles (0.1 mm to 1.0 mm) in a closed circuit fluidized bed reactor by preheated process gas containing CH4, H2, CO (carbon mono oxide), CO2 (carbon di oxide) and water vapour(H2O) at 600 deg C. A 50 mm diameter batch reactor was used for the laboratory tests. This was followed by continuous tests on a 600 mm diameter reactor. Iron ore samples from several countries were tested at Hazen. The product was successfully converted to steel by MEFOS in Sweden in a basic oxygen furnace (BOF) in 1979. After the initial laboratory tests at Hazen Research, Inc., Dr. Stephens applied for a patent and was issued on October 11, 1977 ‘US Patent No. 4,053.301’ by the Patent office of the United States. In 1985 Dr. Stephens retired and acquired the rights to the patent on the iron carbide. He formed a company by name ‘Iron Carbide Development Corporation’...

Circored and Circofer processes of ironmaking Feb24

Circored and Circofer processes of ironmaking...

Circored and Circofer processes of ironmaking Circored and Circofer processes of ironmaking are fluidized bed based iron ore fines reduction processes. These processes completely avoid agglomeration process and make direct use of iron ore fines. Since the processes use non coking coal, necessity of coke oven battery is not there. Fluidized bed technology is ideally suited to energy-intensive processes like direct reduction because it enables high heat and mass transfer rates. Both the Circored and the Circofer processes have been developed by Lurgi Metallurgie GmbH, Germany (now Outotec Oyj, Finland) for the production of direct reduced iron (DRI) from iron ore fines. For both processes, capacities above 1 million tons per annum are possible in a single production unit, resulting in improved economies of scale. Circored process is hydrogen (H2) based process while the Circofer process is coal based. Circored has a two-stage configuration in order to achieve a high metallization of 90 % to 95 %, whereas Circofer has a single-stage configuration which can achieve pre-reduction up to a metallization of around 70 %. Circofer coal-based process produces pre-reduced feed material for smelting reduction reactors, such as AusIron, or electric smelting furnaces – the final product being hot metal or pig iron. Circored process Circored process uses fluidized beds on a scale adopted by Outotec for other applications. Development of the process was initiated in the late 1970s with the pilot plant tests conducted at the ELRED plant of ASEA in Sweden. Tests were also carried out in the 3 tons per hour CFB reactor demonstration unit at Thyssen Stahl in Duisburg, Germany. These tests had focused on the treatment of steel plant wastes. The first commercial Circored unit was built in 1998 by Cliffs and Associates Ltd. at Point Lisas Industrial Complex...

Role of Lubrication during the Process of Metal Working Feb15

Role of Lubrication during the Process of Metal Working...

Role of Lubrication during the Process of Metal Working For understanding the role of lubrication during the processes of metal working, it is important to know the tribology of the lubrication. Tribology consists of boundary friction, which is associated with almost all operations of the metal working. It is caused by the relative movement of two adjacent surfaces under pressure. During the metal working processes, the relative movement between rolls and work piece is improved by the surface speed differential of the rolls Friction Friction plays an important role during metal working process. It is defined as the resistance to relative motion between two bodies in contact. It is an energy dissipating process, causing the temperature at the interface to rise and, if excessive, can result in surface damage. It also influences the deformation taking place in the metal working process. As per the earliest theories, friction is the result of interlocking two rough surfaces sliding along each other. Friction is actually brought on by a large number of variables, such as load, speed, temperature, the materials involved in the sliding pair, and the various effects of fluids and gases at the interface. Most commonly accepted theory of friction is based on the resulting adhesion between the severities of the contacting bodies. It has been seen that regardless of how smooth the surfaces are, they contact each other at only a fraction of their apparent area of contact. Thus, the load during the process of metalworking is supported with few severities in contact. Hence, the normal stress at the severity junctions is high. Under light loads, the contact stresses can only be elastic. However, as the load increases to some of the levels involved in the metal working process, elastic deformation of the severities...

PERED Technology for Direct Reduced Iron Production Jan18

PERED Technology for Direct Reduced Iron Production...

PERED Technology for Direct Reduced Iron Production PERED technology is also known as ‘Persian Reduction’ technology. It is the direct reduction technology invented and patented by ‘Mines and Metals Engineering GmbH’ in 2007. The PERED direct reduction process converts iron oxides, in the form of pellets or lump ore, to highly reduced product suitable for steel making. The reduction of iron oxide takes place without its melting with the help of reducing gases in solid state in a vertical shaft furnace. This technology improves the process of direct reduction for the production of direct reduced iron (DRI). The process is a gas based direct reduction process which has been developed by a team of specialists having experience in different areas of the direct reduction process to ensure that all the flows of different processes are taken care in the main process to obtain optimum and efficient results. The most popular gas used for reduction is reformed natural gas though other gases such as Corex gas and coke oven gas etc. can also be used. PERED technology lowers capital cost, water consumption, maintenance cost, and energy consumption. In PERED, the reduction process takes place at a lesser temperature due to the improved cooling methods and reduced pollutant gas emissions. With less heat, more homogeneous reducing gas, more controllable pellet feed and use of centrifugal compressors, PERED requires less water, electricity and gas to operate, alongside less operational and maintenance expenditure. Output from the PERED direct reduction plants can be in the form of (i) cold direct reduced iron (CDRI), hot briquetted iron (HBI), combination of CDRI/HBI, HBI/hot direct reduced iron (HDRI), and CDRI/HDRI. PERED technology is an improved energy efficient technology and hence economizes energy and resources. It makes optimum use of energy and raw materials...

Mechanical Processes for Descaling of Steel Sep08

Mechanical Processes for Descaling of Steel...

Mechanical Processes for Descaling of Steel Scale is the product of oxidation which takes place during hot rolling. The oxidation and scale formation of steel is an unavoidable phenomenon during the process of hot rolling which involve reheating of steel in a reheating furnace, multi-pass hot rolling and air-cooling in the inter-pass delay times and after rolling. Scale formed during the heating of steel to rolling temperatures in the reheating furnace is known as primary scale. This primary scale is removed before hot rolling. It is usually done for producing steel products with high surface quality and for reducing roll wear. However, secondary scale continues to form on the descaled steel surface during the inter-pass delay time in the roughing and intermediate rolling mills. The colour of primary mill scale is generally bluish black while that of the secondary scale is blue.  The secondary scale gives the steel an appearance which is similar to that of a lacquer coating finish and is often mistaken for a blue coloured primer. The primary scale is composed of three well defined layers of iron oxides. Adjacent to the steel is the thickest layer consisting of wustite having an approximate composition of FeO. The intermediate layer consists of magnetite (Fe3O4) while the outermost layer is hematite (Fe2O3). The thicknesses of these layers depend on several factors linked to the rolling of the steel and the availability of oxygen at the steel surface. The layer at the surface of the steel is richest in oxygen and constitutes 0.5 % to 2 % of scale thickness. The layer at the metal surface is richest in iron and constitutes about 85 % of the scale thickness. The intermediate layer of scale constitutes around 13 % to 14.5 % of scale thickness....