Low Temperature Reduction Degradation Characteristics of Sinter, Pellet and Lump Ore

Wu, Shengli; Liu, Xiaoqin; Zhou, Qi Tony; Xu, Jian; Liu, Chengsong

doi:10.1016/s1006-706x(11)60098-8

Cited by 30 publications

(23 citation statements)

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“…Also, the maximum expansion ratio of lump ores was observed to be higher than that of sinter S and pellet P. In general, the expansion of iron ore is primarily governed by two processes, that is, thermal expansion and expansion caused by reduction of iron oxide. Expansion is mainly affected by microstructure and chemical compositions of iron ores . Reduction degrees of four single iron materials are shown in Figure .…”

Section: Resultsmentioning

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: Resultsmentioning

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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“…All these factors have great influence on the disintegration behaviors of iron ores, leading the disintegration degree of lump ores much heavier in COREX shaft furnace. 9) In the present work, the reduction disintegration behavior of lump ore samples in COREX shaft furnace was studied. The RDI -6.3 of lump ore samples under different temperature, gas composition, and reduction time were measured to study the influencing factors and disintegration mechanism of lump ores.…”

Section: Introductionmentioning

confidence: 99%

“…[3][4][5] The disintegration of iron ores mainly occurs during the reduction process from hematite to magnetite in the temperature zone of 400°C-700°C, and some researchers indicate that the main reason for the disintegration is the stress concentration caused by the volume expansion of magnetite. [6][7][8][9][10] But these studies mainly focus on the disintegration behaviors of iron ores under the blast furnace conditions, especially for sinters and pellets. [11][12][13] However, compared with the blast furnace process, the residence time of iron ores in the low temperature zone of the COREX shaft furnace is much longer, and the CO and H 2 proportion in reducing gas of COREX shaft furnace is also quite higher.…”

Section: Introductionmentioning

confidence: 99%

Reduction Disintegration Behavior of Lump Ore in COREX Shaft Furnace

Liu

2015

ISIJ International

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The heavy disintegration of lump ores would produce plenty of small particles in COREX shaft furnace, which would decrease the gas permeability and productivity of the shaft furnace, thus the proportion of lump ores in the burden of COREX shaft furnace is limited to a low level. In this work, the reduction disintegration behavior of lump ore samples was studied by simulating the reduction process of COREX shaft furnace. The influence of temperature, reduction time and gas composition on the reduction disintegration index (RDI -6.3 ) of lump ore samples were also evaluated. The results showed that the disintegration behavior of lump ores in COREX shaft furnace could be generally divided into three steps and the disintegration mainly occurred in the second step, which was in the temperature zone from 450°C to 650°C with low reduction degree. Meanwhile, the RDI -6.3 of lump ore samples all presented the tendency of "inverted V-shape" in the temperature range from 450°C to 650°C under different reduction time. However, the mutual promotion of reduction reaction and carbon deposition reaction (CDR) was attributed to the main reason for the heavy disintegration of lump ores in COREX shaft furnace. In addition, increasing H 2 concentration in reducing gas and rapid reducing at higher temperature would decrease the disintegration degree of lump ores in COREX shaft furnace.

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“…Several researchers have investigated the mechanical wear/degradation of partially reduced iron ore, especially iron ore lump and sinter, at varied temperatures and using different compositions of the reduction gas. Generally, the ISO 4696‐1 standard is used to determine the reduction disintegration index (RDI) of iron ore (lump, sinter, and pellets) by isothermally reducing it at 500 °C for 60 min using a gas mixture of 20% CO, 20% CO 2 , 58% N 2 , and 2% H 2 .…”

Section: Introductionmentioning

confidence: 99%

“…It has been reported that the maximum wear/degradation of iron ore occurs in the temperature range of 400–600 °C, which is associated with the stress concentrations caused by the volume expansion during the reduction of hematite to magnetite . Furthermore, a higher mass percent of particles smaller than 0.5 mm is produced (≈0.8–3 times higher) due to the reduction degradation of iron ore pellets at 550 °C compared to lump ore and sinter .…”

Section: Introductionmentioning

confidence: 99%

Characterization of Dust Generated during Mechanical Wear of Partially Reduced Iron Ore Pellets

Nabeel

Karasev

Glaser

et al. 2017

steel research int.

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During reduction in a blast furnace (BF), the iron ore pellets undergo structural changes, which facilitate dust generation due to the mechanical wear/disintegration of the pellets. The generated dust decreases the permeability and productivity of the BF process. Thus, this study investigates the mechanical wear of iron ore pellets reduced at 500 8C (P500) and 850 8C (P850) and compares the results to the wear of unreduced pellets (P25). Moreover, the dust generated during the wear experiments is also characterized. It is found that pellets reduced at 500 8C exhibit a %16-35% higher wear rate than reference unreduced pellets. For the pellets reduced at 850 8C, the mechanical wear is inhibited by a formation of a metallic layer at the outer surface of the pellets. Further, the dust generated due to mechanical wear of reduced pellets contain 3-6 times higher amount of coarse particles (>20 mm) as compared to the dust from unreduced pellets. The obtained results are explained on the basis of the structural changes, which take place during the reduction of pellets.

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Low Temperature Reduction Degradation Characteristics of Sinter, Pellet and Lump Ore

Cited by 30 publications

References 0 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

Reduction Disintegration Behavior of Lump Ore in COREX Shaft Furnace

Characterization of Dust Generated during Mechanical Wear of Partially Reduced Iron Ore Pellets

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