Reduction of Reducing Agent Rate in Blast Furnace Operation by Carbon Composite Iron Ore Hot Briquette

Kasai, Akito; Hitoshi, Toyota; Nozawa, Kazuki; Kitayama, Shuji

doi:10.2355/isijinternational.51.1333

Cited by 49 publications

(31 citation statements)

References 7 publications

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“…[6][7][8][9] Many of the results of these studies suggest that the use of carbon composite iron ore in blast furnaces will improve the efficiency of reduction reaction, and thus proves also, as it is reported, the result of its use in a commercially operated blast furnace. [10][11][12] As one of the manufacturing methods of such carbon composite ore, there is a method of manufacturing cement bonded carbon composite iron ore using cement as a binder. 13,14) In the past, tests were carried out of blending a large quantity of cement bonded carbon composite iron ore. 15) But such tests were without any changes of various blast furnace data, such as the carbon consumption rate and on the manufacturing conditions of optimal carbon composite ore.…”

Section: Introductionmentioning

confidence: 99%

Decrease in Carbon Consumption of a Commercial Blast Furnace by Using Carbon Composite Iron Ore

et al. 2012

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Increasing coke gasification rate can lowers the temperature of the thermal reserve zone, resulting in a decrease of carbon consumption and a reduction of the reducing agent rate of blast furnaces. To achieve this increase, the enhancement of coke reactivity itself or the close arrangement of iron ore and carbonaceous materials has been investigated in Japan. Against this, RCA, "Reactive Coke Agglomerate," having a high carbon content, has been developed, and it was found that the agglomerate mixed-in sinter layer had two functions: one having high reducibility itself and the other enhancing the reduction of the surrounding sinter. As a result of the two functions, a significant decrease of the temperature of the thermal reserve zone and an increase of gas utilization by using the agglomerate mixed-in sinter layer in a BIS test was achieved. As for the strength after reaction, disintegration was fairly small in comparison with that of the sinter both in the laboratory scale test and in a basket test using a plant's vertical probe. Long-term plant trials have been conducted at the Oita Works No. 2 Blast Furnace with a maximum use of 54 kg/tHM. It was found that RCA could lower the temperature of the thermal reserve zone and carbon consumption in a commercial blast furnace. Carbon consumption was decreased along the relationship of 0.36 kgC/tHM per 1 kgC/tHM of input carbon from RCA.

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Section: Introductionmentioning

confidence: 99%

Decrease in Carbon Consumption of a Commercial Blast Furnace by Using Carbon Composite Iron Ore

et al. 2012

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“…[1][2][3] Using high reactivity coke or mixing small coke in ore layers can lower the starting temperature of the solution loss reaction, which is nearly consistent with the TRZ temperature. 4,5) In TRZ FeO is under reduction and the CO/(CO + CO 2 ) concentration ratio is approaching to the equilibrium curve of FeO-Fe in Fe-C-O diagram. Lowering TRZ temperature means that FeO reduction temperature is also decreased and accordingly CO gas utilization is shifted to higher efficiency side.…”

Section: Introductionmentioning

confidence: 99%

Morphology Change and Carburization Characteristic of Iron Ore-Coal Composite During Reduction under a Simulated Condition of Blast Furnace

et al. 2019

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Ironmaking process by Blast Furnace (BF) method contributes about 70% of CO 2 emission and energy consumption in steel works. To aim at the sustainable development and environmental protection, decreasing CO 2 emission and energy consumption is always an indispensable task. Using iron ore-coal composite as the raw material of BF is a promising way to mitigate the above issue.In this study, we conducted an experiment procedure which is to simulate the reduction of an iron orecoal composite travelling from the top zone to the cohesive zone of BF. Reduction behavior, morphology changes and carburization characteristic of the composites with the variables of C/O (Carbon to Oxygen) ratio were investigated.As C/O ratio was increased from 0 to 0.6, the reduction rate of composite was accordingly enhanced. It was found that the composite is swelling severely when C/O ratio was lower than 0.4. The swelling occurred in the temperature range from 800°C to 1 100°C which was just under the stage of reduction from wustite to iron. The composite is shattering obviously starting from 1 160°C when C/O ratio was higher than 0.4. It is because the remained free carbon is surplus in reduced iron, causing shattering and powdering. Hence, C/O = 0.4 was suggested to the composite for being charged into BF.

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“…Carbon composite iron ore hot briquette (CCB), as a new type of BF burden for low-carbon and low-temperature ironmaking, is put forward by the researchers in Japan. [9][10][11][12][13][14][15] CCB exhibits great reducibility due to the fact that the coal and iron ore in CCB adjoined closely accelerates the carbon gasification and iron oxides reduction. 16) Previous literature illustrated that carbon composite iron ore could lower the temperature of the thermal reserve and carbon consumption in a commercial BF.…”

Section: Introductionmentioning

confidence: 99%

Volumetric Shrinkage Characteristics and Kinetics Analysis of Vanadium Titanomagnetite Carbon Composite Hot Briquette during Isothermal Reduction

et al. 2018

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The volumetric shrinking characteristics and kinetics of vanadium titanomagnetite carbon composite hot briquette (VTM-CCB) during isothermal reduction were investigated in this paper. It was found that the volumetric shrinking occurs as a combination of a loss of carbon and oxygen from VTM-CCB as well as sintering of iron oxide, suppression of growth of iron whiskers, formation of molten phases, and residual solid carbon content. In the temperature range from 900°C to 1 100°C, the carbon gasification is viewed as the primary factor for the shrinking behavior. In the temperature range higher than 1 100°C, the shrinking of VTM-CCB is mainly caused by the formation of molten slag, liquid iron, and residual solid carbon. It also should be pointed out that, in the higher temperature range, the volumetric shrinkage of VTM-CCB decreased with increasing FC/O ratio, which is mainly due to the fact that a higher FC/O ratio leads to a decreasing of molten slag generation proportion and a suppression of aggregation growth of liquid iron by the increasing of residual solid carbon. Based on the kinetics analysis, The formula for the shrinkage of VTM-CCB during reduction can be obtained, and the value of shrinking activation energy of VTM-CCB decreased obviously from 337.86 kJ/mol to 84.85 kJ/mol with increasing FC/O ratio from 0.8 to 1.4.

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Reduction of Reducing Agent Rate in Blast Furnace Operation by Carbon Composite Iron Ore Hot Briquette

Cited by 49 publications

References 7 publications

Decrease in Carbon Consumption of a Commercial Blast Furnace by Using Carbon Composite Iron Ore

Decrease in Carbon Consumption of a Commercial Blast Furnace by Using Carbon Composite Iron Ore

Morphology Change and Carburization Characteristic of Iron Ore-Coal Composite During Reduction under a Simulated Condition of Blast Furnace

Volumetric Shrinkage Characteristics and Kinetics Analysis of Vanadium Titanomagnetite Carbon Composite Hot Briquette during Isothermal Reduction

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