Occurrence State and Behavior of Carbon Brick Brittle in a Large Dissected Blast Furnace Hearth

Guo, Ziyu; Zhang, Jianliang; Jiao, Kexin; Zong, Yanbing; Wang, Zhongyi

doi:10.1002/srin.202100273

Cited by 11 publications

(7 citation statements)

References 26 publications

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“…It can also be obtained from Figure , especially the small particles accounted for a large proportion in S4. It was worth noting that some small coke particles may float to the tuyere until they were burned where η is the coke consumption rate (%), d lower coke is the coke diameter in the lower parts of the blast furnace (mm), and d upper coke is the coke diameter in the upper parts of the blast furnace (mm).…”

Section: Discussion and Analysismentioning

confidence: 99%

Graphitization and Performance of Deadman Coke in a Large Dissected Blast Furnace

et al. 2021

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The graphitization and performance of deadman coke in the blast furnace hearth have an essential influence on the longevity of the blast furnace. In this paper, coke samples were obtained from various heights in a hearth during the overhaul of the blast furnace. The voidage, particle size, graphitization degree, microstructure, and structure evolution of multiple cokes were analyzed through digital image processing, XRD, Raman spectra, scanning electron microscopy, and energy-dispersive X-ray spectroscopy (SEM-EDS). The graphitization results were compared with feed coke, tuyere coke, cohesive zone coke, and deadman coke in reference, and the main findings were analyzed. The following results were obtained. First, the voidage of deadman coke increased and then decreased with the increase of the depth while the particle size continued to decrease. In addition, the consumption rate of coke as a carburizer, reductant, and heart source was 8.47, 30.95, and 60.58%, respectively. Second, the graphitization degree of deadman coke was extremely high and showed a trend of first increasing and then decreasing. Finally, the evolution mechanism of coke graphitization was proposed. Molten iron, alkali metal, temperature, and mineral were the crucial factors that affect the graphitization of coke. The turning point of the graphitization degree was related to the buoyancy of the hearth.

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Section: Discussion and Analysismentioning

confidence: 99%

Graphitization and Performance of Deadman Coke in a Large Dissected Blast Furnace

et al. 2021

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“…In previous blast furnace dissections, it was found that alkalis were enriched at different height levels of the blast furnace 27) , and the accumulation times of K and Na in the blast furnace can reach 50 times 28) . Alkalis could cause deterioration of coke performance 11) and damage to carbon bricks [3][4][5] . After a large amount of alkalis enters the hearth, it would worsen the active state of the hearth and increase the erosion of carbon bricks.…”

Section: Trace Elements In Slagmentioning

confidence: 99%

“…As a key area for storing slag and iron in the blast furnace, hearth is the limiting aspect of the long life of the blast furnace. In recent years, a large number of blast furnace anatomical studies have found that the enrichment of trace elements in the hearth plays a crucial role in the safe operation of the blast furnace hearth [3][4][5][6][7][8][9][10] . The cyclic enrichment of harmful elements (K, Na, Zn) in the blast furnace aggravates the erosion of the carbon bricks [3][4][5][6] and also deteriorates the metallurgical properties of the coke 11,12) .…”

Section: Introductionmentioning

confidence: 99%

“…In recent years, a large number of blast furnace anatomical studies have found that the enrichment of trace elements in the hearth plays a crucial role in the safe operation of the blast furnace hearth [3][4][5][6][7][8][9][10] . The cyclic enrichment of harmful elements (K, Na, Zn) in the blast furnace aggravates the erosion of the carbon bricks [3][4][5][6] and also deteriorates the metallurgical properties of the coke 11,12) . The increased sulfur content in molten pig iron promotes the erosion of carbon bricks 13) .…”

Section: Introductionmentioning

confidence: 99%

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Migration Behavior of K, Na, S, Ti in Hearth of a Commercial Blast Furnace

Liu

Zhang

et al. 2022

ISIJ Int.

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In-depth understanding of the existence state and migration behavior of K, Na, S, Ti in the BF hearth is essential to improve the campaign life and optimize the operation process of the blast furnace. In the study, deadman and carbon brick samples were extracted along the radial direction from a large commercial BF during dissection investigation. The microscopic morphology of the samples and the migration behavior of K, Na, S, Ti were analyzed. It was found that a layer of minerals existed on the surface of deadman coke in hearth, and high melting temperature phases such as CaS and TiN as well as slag with high aluminum were existed at the coke-slag-iron interface. K, Na compound present widespread in the deadman coke and carbon brick. The formation of mineral layer reduced the coke dissolution rate, thereby delaying the renewal rate of the deadman. With the dissolution of coke, minerals flow out from the surface of coke and precipitate as alumina and MgAl 2 O 4 spinel, which reduces the voidage of the deadman. Meanwhile, slag is sufficiently desulfurized with the iron to form a large amount of CaS accumulation at the hearth sidewall, which intensifies the iron circulation and increases the erosion of carbon brick. When the slag is in contact with the refractory, the K, Na contained in the slag provides a source of alkalis attack on the carbon bricks, and the Ti in the slag provides the possibility of forming a protective layer containing titanium on the sidewall of the hearth.

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“…Furthermore, the carburization behavior of molten iron on refractories also governs the lifespan of blast furnaces. [ 6 ] Thus, understanding the wetting behavior of molten iron on carbonaceous refractories is indispensable for exploring a path toward low‐carbon emissions and prolonged lifespan in blast furnace smelting.…”

Section: Introductionmentioning

confidence: 99%

Wettability Characteristics of Nanoporous Carbon Bricks Incorporated with Al₂O₃ Phase and Molten Iron in Sustainable and Low‐Carbon Blast Furnace

Liu,

Guo,

Wang

et al. 2024

steel research int.

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Analyzing the wetting behavior between carbon brick and molten iron in a blast furnace is crucial for understanding prolonging the furnace's lifespan. This study investigates the wetting behavior between microporous carbon brick and molten iron. The contact angle between the carbon brick and molten iron is measured at various temperatures and carbon saturation conditions, while the microscopic morphology of the reacted interface is examined. Furthermore, the wetting mechanism of molten iron on the carbon brick surface is elucidated. The findings reveal that both the microporous carbon brick and molten iron remain in a never‐wetting state within the furnace. As the temperature rises from 1150 to 1450 °C, the contact angle decreases from 138° to 128°, whereas the initial carbon content in the molten iron increases from 2.6 wt% to 4.1 wt%. Additionally, the initial contact angles gradually increase from 128.3° to 133.6°, with final equilibrium contact angles of 119.2° to 127.0°, indicating a nonwetting state. The carbon dissolution reaction occurs within the carbon matrix region of the microporous carbon brick prior to carbon saturation in the molten iron. Conversely, the presence of a ceramic phase in the ceramic area hampers both chemical erosion and physical penetration of the molten iron.

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Occurrence State and Behavior of Carbon Brick Brittle in a Large Dissected Blast Furnace Hearth

Cited by 11 publications

References 26 publications

Graphitization and Performance of Deadman Coke in a Large Dissected Blast Furnace

Graphitization and Performance of Deadman Coke in a Large Dissected Blast Furnace

Migration Behavior of K, Na, S, Ti in Hearth of a Commercial Blast Furnace

Wettability Characteristics of Nanoporous Carbon Bricks Incorporated with Al₂O₃ Phase and Molten Iron in Sustainable and Low‐Carbon Blast Furnace

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Occurrence State and Behavior of Carbon Brick Brittle in a Large Dissected Blast Furnace Hearth

Cited by 11 publications

References 26 publications

Graphitization and Performance of Deadman Coke in a Large Dissected Blast Furnace

Graphitization and Performance of Deadman Coke in a Large Dissected Blast Furnace

Migration Behavior of K, Na, S, Ti in Hearth of a Commercial Blast Furnace

Wettability Characteristics of Nanoporous Carbon Bricks Incorporated with Al2O3 Phase and Molten Iron in Sustainable and Low‐Carbon Blast Furnace

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Product

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About

Wettability Characteristics of Nanoporous Carbon Bricks Incorporated with Al₂O₃ Phase and Molten Iron in Sustainable and Low‐Carbon Blast Furnace