Evaluation of Softening, Shrinking and Melting Reduction Behavior of Raw Materials for Blast Furnace

Nishimura, Tsunehisa; Higuchi, Kenichi; Naito, Masaaki; Kunitomo, Kazuya

doi:10.2355/isijinternational.51.1316

Cited by 66 publications

(41 citation statements)

References 8 publications

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“…BF is conceptually divided into zones, according to the temperature, chemical reactions and the oxidation state of iron, such as lumpish zone and cohesive zone . The shape and position of the cohesive zone in blast furnace has a pronounce effect on the gas flow pattern, which in turn alters the efficiency and productivity of the blast furnace process . The high temperature properties of ferrous burden largely control the shape, width, and position of cohesive zone.…”

Section: Introductionmentioning

confidence: 99%

Influence of High Temperature Interaction on the Softening and Melting Behaviors of Iron Bearing Materials in the Blast Furnace

Wang

et al. 2018

steel research int.

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The cohesive zone in the blast furnace is largely affected by the softening and melting behaviors of ferrous burden. The Visual High Temperature Method (VHTM) has been employed, in present work, to explore the softening and melting behavior of sinter, two different types of lump ores, and one acid pellet. All iron bearing materials are observed to swell before they shrink. This observation is more dominant in case of dense structured lump ore B. The shrinking temperature intervals are different from one another. This contributes to the gas permeability of ore layer in the cohesive zone because “ore window” is formed. In addition to this, the softening and melting behavior of mixed burdens (consist of sinter and other acid materials) have also been studied. Results display that the softening and melting behavior of all materials are improved. This observation is more dominant for lump ore A. It is attributed to high temperature interactions between sinter and acid iron bearing materials. The high temperature interactivity is largely influenced by the chemical compositions, pore structure, and contact condition. Experimental results of two groups of integrated burdens verify the importance of high temperature interaction for improving the softening and melting characteristics of iron bearing materials.

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Section: Introductionmentioning

confidence: 99%

Influence of High Temperature Interaction on the Softening and Melting Behaviors of Iron Bearing Materials in the Blast Furnace

Wang

et al. 2018

steel research int.

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“…Another weakness is that some softening studies comprise only an individual pellet 16,17) or a couple of pellets 2,3,[9][10][11][12][13][14][15]18) instead of a packed bed of pellets. 7,8,[19][20][21][22][23][24][25][26][27][28][29][30] Studies 2,7,[21][22][23][24][25][26][27][28][29] have been carried out for iron ore pellets under load dynamically from ambient temperature to elevated temperatures using a simulated BF gas. Recently, Guha and Sinha 29) presented a modified softening-melting test with a possibility to use a gas composition varying with temperature/time to better simulate the actual conditions in a BF.…”

Section: Introductionmentioning

confidence: 99%

Evaluating the Reduction-Softening Behaviour of Blast Furnace Burden with an Advanced Test

et al. 2016

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A ferrous burden loses its permeability in the cohesive zone of a Blast Furnace (BF), where the iron burden materials soften and melt. A tailor-made, high-temperature furnace named ARUL (Advanced Reduction under Load) was used here to study the reduction-softening behaviour of acid and olivine pellets and basic sinter under simulated BF gas, temperature and pressure conditions.The ARUL test showed the best reduction-softening properties for the basic sinter. The sinter sample resisted up to 1 329°C and achieved a reduction degree of 90.2% until a gas-impermeable structure was formed in a packed bed, whereas the acid pellet lost its permeability at 1 160°C and only reduced to a reduction degree of 48.7%. The olivine pellet had intermediate reduction-softening properties with a final temperature of 1 252°C and a final reduction degree of 68.7%. The differences between the test materials were assessed as being caused mainly by different chemistry, but it was also revealed that the sinter sample remained its macro-porosity markedly better in relation to the pellets, providing routes for reducing gases.The experimental results were compared to the phase diagrams calculated with the computational thermodynamic software FactSage. Phase diagrams for the 5-component FeO-SiO 2 -CaO-MgO-Al 2 O 3 systems with constant CaO, MgO and Al 2 O 3 contents were used to estimate the formation of liquid phases in the test materials. The computed phase diagrams gave an estimate of the liquid formation; however, some limitations were also found in the utilization of the computations because of the need to define the system in certain simplicity.

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“…While, the high temperature properties of blast furnace slags play an important role on the softening and melting behavior of raw materials in blast furnace. 1,2) Many researchers have found that the chemical composition, such as CaO/SiO2, Al2O3 and MgO content, have great influence on the fluidity and viscosity of blast furnace slags. [3][4][5] On the other hand, researchers also found that the sinter of high basicity would interact with lump ores or pellets at high temperature, the softening and melting properties of lump ores or pellets would be improved by the high temperature interaction.…”

Section: Introductionmentioning

confidence: 99%

Influence of High Temperature Interaction between Sinter and Lump Ores on the Formation Behavior of Primary-slags in Blast Furnace

Liu

Huang

et al. 2014

ISIJ Int.

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The primary-slags formation behaviors of sinter, lump ores and integrated burdens were studied to explore the high temperature interaction between sinter and lump ores in blast furnace. The results showed that the softening and melting properties of lump ores, viscosity and fluidity index of primaryslags of lump ores would be improved by the high temperature interaction. Particularly, the high temperature interaction was influenced by the chemical composition and porosity of iron ore samples. The high temperature interaction between sinter and lump ore L-2 (a typical limonite lump ore from Australia) was much stronger. Though the high temperature properties of lump ore L-2 was much worse than lump ore L-1 (a typical hematite lump ore from South Africa), the high temperature properties of integrated burden B (consist of sinter and lump ore L-2) was not worse than that of integrated burden A (consist of sinter and lump ore L-1) due to the strong high temperature interaction. In addition, the suitable MgO/Al2O3 weight ratio was calculated based on the assumption that the only phases of slags were akermanite and gehlenite, which showed a decreasing tend with the increase of CaO/SiO2 weight ratio.

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Evaluation of Softening, Shrinking and Melting Reduction Behavior of Raw Materials for Blast Furnace

Cited by 66 publications

References 8 publications

Influence of High Temperature Interaction on the Softening and Melting Behaviors of Iron Bearing Materials in the Blast Furnace

Influence of High Temperature Interaction on the Softening and Melting Behaviors of Iron Bearing Materials in the Blast Furnace

Evaluating the Reduction-Softening Behaviour of Blast Furnace Burden with an Advanced Test

Influence of High Temperature Interaction between Sinter and Lump Ores on the Formation Behavior of Primary-slags in Blast Furnace

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