Observation of Deadman Samples in a Dissected Blast Furnace Hearth

Zhang, Lei; Zhang, Jianliang; Jiao, Kexin; Zhongping, Zou; Zhao, Yunjian

doi:10.2355/isijinternational.isijint-2019-244

Cited by 17 publications

(14 citation statements)

References 13 publications

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“…The voidage and particle size of coke samples were calculated by eqs 1 and 2. 3 It is worth noting that the numerical error of both voidage and particle size is about 1%.…”

Section: Methodsmentioning

confidence: 99%

“…The deadman occupies 70% of the volume of the blast furnace hearth. 3,4 The performance of hearth coke directly determines the hearth activity, production capacity, and longevity potential of the blast furnace. 5−9 Therefore, it is necessary to study the performance of the hearth coke, particularly its graphitization degree and consumption pathway.…”

Section: Introductionmentioning

confidence: 99%

“…It takes a long time for coke to be renewed in the blast furnace hearth, so the accumulation of coke for a long time leads to the formation of deadman. The deadman occupies 70% of the volume of the blast furnace hearth. , The performance of hearth coke directly determines the hearth activity, production capacity, and longevity potential of the blast furnace. − Therefore, it is necessary to study the performance of the hearth coke, particularly its graphitization degree and consumption pathway. The degree of coke graphitization and consumption pathway are influenced by the target annealing time and temperature, which can reflect the renewal time of the blast furnace.…”

Section: Introductionmentioning

confidence: 99%

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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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“…The voidage and particle size of coke samples were calculated by eqs 1 and 2. 3 It is worth noting that the numerical error of both voidage and particle size is about 1%.…”

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

et al. 2021

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“…Blast furnace overhaul is an important opportunity and effective means for macrocognition of the blast furnace. [ 18–21 ] During the blast furnace hearth dissection of a Chinese commercial blast furnace, many floating refractories were found in residual iron, which is strong support for the theory of brittle carbon bricks and is also one of the important reasons for the abnormal corrosion of carbon bricks. Therefore, it is necessary to systematically study the occurrence state of carbon bricks in the blast furnace, which will help to further clarify the behavior of carbon bricks in the blast furnace hearth.…”

Section: Introductionmentioning

confidence: 89%

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

Guo

Zhang

Jiao

et al. 2021

steel research int.

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The thickness of the carbon bricks is one of the important factors of the longevity of the blast furnace. Herein, a large number of brittle carbon bricks in the hearth sidewall and the continuous rectangle‐shape floating refractory in residual iron are found during the blast furnace hearth dissection. The occurrence state of the carbon brick is characterized through chemical analysis, X‐ray diffraction (XRD), and scanning electron microscope (SEM)–energy‐dispersive X‐ray spectroscopy (EDS). The contents of K, Na, Cl, Zn, and Fe in brittle carbon bricks are relatively high, and a large number of large‐scale Al2O3 phases and nepheline appear in the floating carbon brick. It indicates that K, Na, Cl, Zn, and Fe are major causes for the serious erosion of the carbon brick, and the floating carbon brick may come from brittle carbon bricks on the sidewall. In addition, the source of Al2O3 and the consumption pathway of SiO2 and ZnO in floating refractory in residual iron are analyzed. Finally, the disappearing mechanism of carbon brick is proposed, which is that the carbon bricks floated up to the tuyere and burnt.

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“…The more specifically structure of blast furnace hearth and sample information could be found in my previous work. 15) A series of samples were taken out from core sample and the samples were not completely evenly distributed for the selection of samples position is mainly determined by the appearance of the sample and following the principle of average distribution. These samples were named as D30, D40, etc., which means the sample is 30 mm or 40 mm from the cold side.…”

Section: Samplesmentioning

confidence: 99%

Phase Composition and Properties Distribution of Residual Iron in a Dissected Blast Furnace Hearth

Zhang

Jiao

et al. 2020

ISIJ Int.

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Dissection research is the most meaningful way to understand the internal conditions of blast furnace. Because it can obtain samples from hearth after a blast furnace was shut down. In this paper, a 2 200 m 3 commercial blast furnace was shut down with residual iron remained inside. And then core drilling method was used to obtain a horizontal sample of residual iron, which was located 1 610 mm below the centerline of taphole and had a length of 1 840 mm. A variety of techniques, such as scanning electron microscopyenergy dispersive spectroscopy (SEM-EDS), Optical Microscope, X-ray diffraction (XRD) and Raman spectroscopy were applied to analysis the microscopic morphology, phase composition and properties distribution of residual iron samples at different position. The results show that complex phases appear near the cold side, including Fe, C, Ti 3 N 2 , KAlSi 2 O 6 and Al 2 O 3. And distribution of properties along the core sample from inside to cold side like density, degree of graphitization and thermal diffusion also have a big change. These results are considered to be related to the function of cooling system. KEY WORDS: dissection of blast furnace; Ti 3 N 2 ; KAlSi 2 O 6 ; density; degree of graphitization; thermal diffusion.

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Observation of Deadman Samples in a Dissected Blast Furnace Hearth

Cited by 17 publications

References 13 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

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

Phase Composition and Properties Distribution of Residual Iron in a Dissected Blast Furnace Hearth

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