Iron Carbide

Iron Carbide Iron carbide is a high melting point, non-pyrophoric, strongly magnetic synthetic compound obtained in granular or powder form. It is composed of three atoms of Fe and one atom C and its chemical formula is Fe3C. The commercial iron carbide consists of around 90 % total iron and around 6 % to 6.5 % of total carbon. The primary use of the product is as a metallic charge during steelmaking for substitution of hot metal, direct reduced iron, or steel scrap. Iron carbide is an intermetallic compound of iron and carbon. It is, more precisely, intermediate transition metal carbide. Its stoichiometric composition consists of 6.67 % carbon and 93.3 % iron (Fe) by weight. It has an orthorhombic crystal structure (Fig 1). It is a hard, brittle material and normally classified as a ceramic in its pure form. It is a frequently found and important constituent in ferrous metallurgy. While iron carbide is present in most steels and cast irons, it is produced as a raw material by the iron carbide process, which belongs to the family of alternative ironmaking technologies. Fig 1 Crystal of iron carbide Iron carbide is a premium quality feed for steelmaking in electric arc furnaces and basic oxygen furnaces. It is available as dark gray granules or powder. It offers matchless metallurgical advantages and outstanding cost savings. It has a density of 7.64 kg/cu m and is thus slightly denser than the liquid iron, which has a density of 6.98 kg/cu m. The iron carbide is composed of three atoms of Fe and one atom C and is also known as cementite. Cementite is an intermetallic compound which is hard, brittle, and metastable because it tends to decompose in ferrite (or austenite) and graphite according to the reaction Fe3C = 3 Fe + C. In fact, this transformation is not...

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...

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...

HYL Process for Direct Reduction of Iron Ore Apr22

HYL Process for Direct Reduction of Iron Ore...

HYL Process for Direct Reduction of Iron Ore HYL process is designed for the conversion of iron ore (pellet/lump ore) into metallic iron, by the use of reducing gases in a solid-gas moving bed reactor. Oxygen (O2) is removed from the iron ore by chemical reactions based on hydrogen (H2) and carbon monoxide (CO) for the production of highly metallized direct reduced iron (DRI)/hot briquetted iron (HBI). HYL process is presently marketed under ‘Energiron’ trademark. HYL process for direct reduction of iron ore was the fruition of research efforts begun by Hojalata y L.mina, S.A. (later known as Hylsa), at the beginning of the 1950s. After the initial evaluation of the concept, it was decided to install a process using a tunnel furnace and several runs were undertaken. The first batch was made by using an ancient furnace (which had been built to heat plate) on the 5th of July, 1950. One part of crushed ore of size ranging from 12 mm to 25 mm was mixed with 40 % coke breeze and 15 % limestone of the same granulometry as the ore. This mixture was put into clay crucibles and into 2 iron pipes, each one with a diameter of 100 mm and a length of 1 meter. 20 kg of good quality of DRI was produced. The first gas based plant, with a design capacity of 50 tons per day, was unable to reach acceptable levels of metallization. During the 18 months of its operation, it underwent several changes, including the installation of a natural gas reformer with the object of improving the reducing gas. Finally, its operation was suspended during early 1955. After this discouraging attempt, several experiments were carried out and a pilot plant was assembled to put the new...

Midrex Process for Direct Reduction of Iron Ore Apr09

Midrex Process for Direct Reduction of Iron Ore...

Midrex Process for Direct Reduction of Iron Ore Midrex is an ironmaking process, developed for the production of direct reduced iron (DRI). It is a gas-based shaft furnace process is a solid state reduction process which reduces iron ore pellets or lump ore into DRI without their melting using reducing gas generally formed from natural gas. The principle of the reduction process using reducing gas is shown in Fig 1. Fig 1 Principle of reduction process using reducing gas The history of the Midrex process goes back to 1966 when Donald Beggs of the Surface Combustion Corporation conceives the idea for the Midrex direct reduction process.  The original process was developed by the Midland-Ross Co., which later became Midrex Technologies, Inc. It is now a wholly owned subsidiary of Kobe Steel. A pilot plant was built in Toledo, Ohio in 1967. The first commercial plant, having a production capacity of 150,000 tons per year, was built in Portland, Oregon, in 1969. The genius of the Midrex process is its simplicity. Donald Beggs’ concept of combining stoichiometric natural gas reforming with shaft furnace direct reduction of iron ore was a breakthrough innovation which has stood the test of time. Since 1969, DRI production through Midrex process has crossed 500 million tons. Production from many of the Midrex plants exceeds their design capacity. Each year since 1987, DRI production through Midrex process is over 60 % of the total global production of DRI. The process was immature in 1978, when Kobe Steel began the construction of a plant with a production capacity of 400,000 tons/year in the State of Qatar. Kobe Steel significantly modified the design, exploiting the company’s technologies developed through blast furnace operation, and stabilized the then new process. On the other hand, Midrex...