Corex Process for Production of Iron. During the late twentieth century, several new initiatives have been taken for the development of the. COREX PROCESS in IRONMAKING Report Submitted by: Aditya Kumar Singh ( ), Bachelor in Technology, Metallurgy & Materials. A brief technical review about what is COREX process of iron making, some merits and demerits of COREX technology.
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In provess regards, organic sulphur in the coal gasifies and is absorbed by the DRI and returned to the melter-gasifier as iron sulphide.
In the two-stage operation of the process DRI produced from a shaft furnace is charged into a melter-gasifier for smelting. The outputs can be used either by integrated mills or EAF electric arc furnace mills.
Views Read Edit View history. It takes only half an hour to stop the plant and only four hours to restart it. Leave a Reply Cancel reply Your email address will not be published. The Melter gasifier has three main sections, the gaseous free board zone, the Char bed, and the hearth zone, and it has an effect on several stages in the process.
Corex Process for Production of Iron
Emission values are already far below the maximum values allowed by future standards. Specific melting capacity is higher than that in Blast Furnace; productivity around 3. By fulfilling more stringent ecological regulations by law, utilization of low-cost, highly available low grade raw materials including fines, the COREX process has been accepted as a commercially proven technology for present and future iron making process.
Corex process is one of these initiatives.
Donate Grateful for your donation! Out of the above mentioned reactions, reactions for the reduction of iron oxide by hydrogen and calcination are endothermic, while the reactions for the reduction of iron oxide by CO gas and carbon deposition are exothermic in nature. The second stage of forex process consists of melting and carburizing of hot DRI by the coal and oxygen which is added in the meter-gasifier.
Further due to the in-situ coking of the coal in the melter-gasifier, a large portion of sulphur is captured in the slag, dramatically decreasing emissions of gaseous SO2 or H2S. 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.
Today Corex technology is an acknowledged process for producing liquid hot metal in a quality which is identical to hot metal produced in oron blast furnace.
Corex Process | Industrial Efficiency Technology & Measures
The melter-gasifier can largely be divided into three reaction zones namely i gaseous free board zone upper part or domeii char bed zone middle part above oxygen tuyeresand iii hearth zone lower part below oxygen tuyeres. The process is the only alternative to the conventional blast procfss route consisting of sinter plant, coke oven and blast furnace. The exothermic combustion provides the energy to complete the reduction of the hot DRI and to melt the slag and iron.
After being reduced, the DRI is redirected to the char bed where the iron and slag are melted and then directed to the hearth zone.
Corex Process – Wikipedia
Advantages of the Corex process include i reduction in the specific investment cost compared with conventional blast furnace route of production, ii lower production cost, iii better environmental performance because of lower emissions and discharges, iv higher calorific value of export gas makes it suitable for use in a wide range of applications, v flexible with regards to the raw material uses since a wide variety of iron ores and coals can be used, vi good operational flexibility with respect to production capacity, production stops and raw material changes.
Due to continuous gas flow through the char bed, there also exists a fluidized bed in the transition area between the char bed and the free board zone. Direct use of non-coking coal is possible since the coal is charred inside the melter gasifier. Use of high purity oxygen in the Corex process generates of nitrogen free top gas. As far as coal is concerned, the non-coking coals having too high volatile matter VM or too low fixed carbon FC cannot be used in corex process of iron making.
The rest of the hot gas is then cooled and sent into the reduction shaft resulting in the Corex export gas which is used to control pressure in the plant.
The volatile matter is driven off and shattered fixed carbon particles fall into the gasification zone where oxygen is injected through blast furnace type tuyeres to burn the carbon to carbon monoxide CO.
Limitations of the Corex process include i optimized distribution of coal and DRI is needed in the melter-gasifier to avoid peripheral flow of hot gases, ii absence of post combustion results into the loss of the chemical energy in the export gases resulting into high consumption of coal, iii many of the equipments such as cooling gas compressor are maintenance oriented, iv transfer of hot DRI and recycling of the hot gas are hazardous especially during their maintenance periods, vi melter-gasifier is subjected to high occurrence of pressure peaks on account of use of raw coal with poor char bed conditions resulting into jamming of dust recycling systems as well as gas cleaning systems, vii sensitiveness of the process inputs quality parameters such as granulometry, percentage of fines proces the inputs, decrepitation, and degradation behaviour of coal, iron ore and pellets at high temperature.
This module has a hearth diameter of 7. Unlike the conventional Blast furnace route for production of hot metal, it can accept high alkali containing ores without any build up inside the reactor.
Phenols discharge is pprocess 0. Metallurgical coal is not only costly but is associated with environmental issues during its conversion to BF coke in the coke oven batteries. The attractiveness of the Corex process is due to i hot metal quality suitable for steelmaking, ii low investment and operational costs due to the elimination of coke ovens and by product plant, iii low process related emission rates, iv use of a wide variety of iron ores and especially non-coking coals, and v generation of a highly valuable export gas which can be used for various purposes such as electric power generation, DRI production, or jaking gas substitution.
The schematic process flow sheet is shown in Fig 1 and the schematic view of main Corex plant sections is shown in Fig 2. The hot metal produced has carbon and silicon contents similar to blast furnace hot metal.
The general applicability of this first generation process was limited and a lot of technical problems ironn to be solved. Your email address will not be published. The gas at the temperature range of 1, deg C to 1, deg C from the melter-gasifier is cooled to the reduction gas temperature deg C to deg C by the addition of cooling gas.
The heat and mass balance calculation for an ironmaking process plays an important role during the operation of Correx process. 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.
Fig 3 Comparison of concepts of blast furnace route and Corex route.
Corex process was developed by the Austrian technology supplier VOEST in the late s, and its feasibility was confirmed during the s.
Due to its high calorific value, this gas can be recycled for reduction work or used for heat or energy generation.
Meanwhile, in a two-stage process, like Corex, the ore is reduced in one shaft and melted and purified in another. It is an industrially and commercially proven direct smelting reduction process which allows for cost-efficient and environmentally compatible production of hot metal directly from iron ore and non-coking coal. Retrieved from ” https: The hot metal temperature is around deg C to deg C.
Retrieved October 16, First it serves to create the reduction gas by gasifying the coal with oxygen and then cooling it. Many of the gases resulting from this process can then be recycled or used to produce electricity.