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COREX (Two stage): Operating commercially
FINEX (Two stage): Operating commercially
HISMELT(Single stage):NotbeingOperatingcommercially at present.
Single stage: Reduction & melting in the same vessel
Two stage : Reduction in one vessel; melting in the 2nd vessel
COREX PROCESS
• Corex is a smelting reduction process combining a melter gasifier with a reduction shaft.
• The process takes lump iron ore or pellets, non-coking coal, and oxygen as main inputs. Similar to the blast furnace process, the reduction gas moves in counter flow to the descending burden in the reduction shaft. Then, the reduced iron is discharged from the reduction shaft by screw conveyors and transported via feed legs into the melter gasifier.
• The gas containing mainly of CO and H2, which is produced by the gasification of coal with pure O2 leaves the melter gasifier at temperatures between 1000 and 1050 °C.
• Undesirable products of the coal gasification such as tar, phenols, etc. are destroyed and not released to the atmosphere.
• The gas is cooled to 800-850C and cleaned from dust particles. After reduction of the iron ore in the reduction shaft, the top gas is cooled and cleaned to obtain high caloric export gas.
• The main product, the hot metal can be further treated in either EAF or BOF or can be cast and sold as pig iron.
MAIN FEATURES
• Dry fuel consumption with and without off-gas recycling is reported to be
770 kg/t-HM and 940 kg/t-HM.
• With a combined cycle power plant and off-gas recycling combined, the net thermal and electrical energy consumption for a 1 million t/y capacity plant is reportedto be 450 and 45 MW, respectively.
• CO2 emissions per ton of combined product (hot metal + DRI) are lower by ~20% compared to blast furnace route.
• Total CO2 emissions for steel produced with 60% hot metal from Corex and
40% DRI is reported to be around 3.78 t/t-steel.
• Reported capital costs were in the range of €195 per ton of annual production.
• Capital and operational costs for producing steel with 60% Corex hot metal and 40% DRI is reported to be $373.5 and $218.3 per ton of steel, respectively.
FINEX PROCESS
• Finex is a fluidized-bed smelting reduction process, and is considered to be a more advanced form of Corex process.
• Its core plant consists a melter-gasifier, which melts the DRI and gassifies the coal, and a series of successive fluidised beds that reduce ore fines to DRI. The technology utilizes fine ore and non-coking coal.
• Iron ore is first pre-reduced in fluidized-bed reactors by reducing gas coming from melter gasifier.
• Subsequently, hot metal is produced in the melter gasifier.
• Coal and oxygen are supplied in the melter gasifier.
MAIN FEATURES
• Coal consumption of the process is less than 700 kg-coal/t-HM.
• An additional energy reduction of 1.3 GJ/t-HM is reported by utilizing off-gases after CO2 removal.
• The process is reported to have 4% less CO2 reductions, as compared to blast furnace route.
• According to the company, the capital and operational costs of Finex are 15 – 20% lower than conventional BF route.
HISMELT PROCESS
• HIsmelt is short for high intensity smelting.
• It is a direct smelting process for making liquid iron straight from the iron ore.
• The process has been developed to treat iron ore fines with minimum pretreatment, making the process more flexible in terms of the quality of iron ore it can treat.
• The process allows the use of non coking coal and iron ore fines with significant impurities.
• The core of the HIsmelt process is the smelt reduction vessel (SRV) which has a refractory lined hearth and water cooled upper shell.
• The process is carried out in this vessel.
• The refractory hearth contains the molten iron bath and liquid slag.
• The main product of the process is liquid iron or hot metal which can be used in steel melting shop or cast in pig casting machine to produce pig iron.
• The byproduct of the process is slag and the off gas.
MAIN FEATURES
• The method of solid injections using high speed lances ensure that the capture efficiency in the melt is high and even ultra fines can be used directly.
• The ‘natural’ 5 % to 6 % FeO level in the slag in conjunction with the metal carbon at 4 % creates conditions for strong partition of phosphorus from metal to slag. Typically around 80 % to 90 % of phosphorus goes to slag.
• Coal performance has virtually no dependence on particle morphology, since the coal is ground fine for injection
• No toxic emissions. Brings emissions of dioxins and furans to a nil level.
• Reduction in CO2 emissions by 20 %
• Reduction of Sox emissions by 90 %
• Reduction in NOx emissions by 40 %