Characterization of Prebake Anodes by Micro X-ray Computed Tomography

Rørvik, Stein; Lossius, Lorentz Petter

doi:10.1007/978-3-319-51541-0_148

Cited by 7 publications

(4 citation statements)

References 6 publications

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“…Comparing with the XCT measurements of other carbon refractory materials, the measured total porosity was higher than for the carbon anodes (1.96-3.46%) investigated by Rørvik et al [27], while the continuous porosity was much lower than for amorphous carbon blocks (6-7%) investigated by the Steenkamp et al [28]. However, it should be noted that those measurements were performed for XCT investigations with different voxel sizes (7.3 × 7.3 × 7.3 µm 3 [28] and 27 × 27 × 27 µm 3 [27]) than in this study. Results showed that even using this relatively high resolution (16 × 16 × 16 µm 3 ), we are able to observe the elements of continuous pore structure, which serve as a preferred flow path for molten metal infiltration.…”

Section: Discussionmentioning

confidence: 45%

“…z.o.o., Racibórz, Poland) using other methods, i.e., mercury intrusion porosimetry (16.62 ± 1.09%) or helium porosimetry (18.66 ± 0.70%) [41]. Comparing with the XCT measurements of other carbon refractory materials, the measured total porosity was higher than for the carbon anodes (1.96-3.46%) investigated by Rørvik et al [27], while the continuous porosity was much lower than for amorphous carbon blocks (6-7%) investigated by the Steenkamp et al [28]. However, it should be noted that those measurements were performed for XCT investigations with different voxel sizes (7.3 × 7.3 × 7.3 µm 3 [28] and 27 × 27 × 27 µm 3 [27]) than in this study.…”

Section: Discussionmentioning

confidence: 78%

“…Based on the XCT measurements, methods for determining parameters describing pore structure-tortuosity [23] and constrictivity [24]-were developed. Only for carbon and graphite refractory materials, XCT has been used to investigate the pore structure of micropore carbon materials [25], microstructure and tortuosity analysis of carbon anodes for aluminum smelting [26,27] and for porosity investigations of carbon blocks and ramming paste used for silicomanganese production [28].…”

Section: Introductionmentioning

confidence: 99%

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Investigation of Molten Metal Infiltration into Micropore Carbon Refractory Materials Using X-ray Computed Tomography

et al. 2021

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The lifetime of a blast furnace (BF), and, consequently, the price of steel, strongly depends on the degradation of micropore carbon refractory materials used as lining materials in the BF hearth. One of the major degradation mechanisms in the BF hearth is related to the infiltration and dissolution of refractory materials in molten metal. To design new and more resilient materials, we need to know more about degradation mechanisms, which can be achieved using laboratory tests. In this work, we present a new investigation method of refractory materials infiltration resistance. The designed method combines a standard degradation test (hot metal penetration test) with X-ray computed tomography (XCT) measurements. Application of XCT measurements before and after molten metal infiltration allows observing changes in the micropore carbon refractory material’s microstructure and identifying the elements of the open pore structure that are crucial in molten metal infiltration.

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Section: Discussionmentioning

confidence: 45%

Section: Discussionmentioning

confidence: 78%

Section: Introductionmentioning

confidence: 99%

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Investigation of Molten Metal Infiltration into Micropore Carbon Refractory Materials Using X-ray Computed Tomography

et al. 2021

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“…Porosity was also investigated using an optical microscope (high-end Leica/Reichert MeF3A metallurgical optical reflected light microscope) and a custom written macro for the NIH software as described by Rørvik and Øye. 39 The porosity size range of the measurements using this method was 5-10000 μm diameter. Two parallel samples were tested for all these analyses.…”

Section: Methodsmentioning

confidence: 99%

Comparing Anodic Bubble Behavior of Anodes from Anisotropic and Isotropic Cokes in Laboratory Scale Aluminum Electrolysis Cells

Sommerseth

Thorne

Ratvik

et al. 2019

J. Electrochem. Soc.

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During production of aluminum in Hall-Héroult cells, carbon anodes electrochemically oxidize to form mainly CO2. The CO2 bubbles block the anode working surface during growth and coalescence, leading to cell voltage loss and voltage oscillations. Lower grade isotropic petroleum cokes are currently being introduced to anodes worldwide, but little is known about effects of coke quality on the unavoidable voltage losses linked to bubble formation. To investigate this, a pilot carbon anode series was made with various blended ratios of isotropic to anisotropic coke. The anodes were characterized with respect to voltage oscillations related to bubble formation and release, wettability towards electrolyte and surface roughness before and after electrolysis. Results showed that voltage noise caused by gas bubbles was reduced for anodes containing isotropic coke. For blended anodes of isotropic and anisotropic coke, the potential oscillation amplitude was reduced by ~0.19 V compared to a 100 % anisotropic coke anode. The percentage of the anode surface screened by gas bubbles was also reduced as isotropic coke was introduced. Increased wettability between electrolyte and two anodes containing isotropic coke was observed after anode polarization. The reduced bubble screening on the anode surface was attributed to better wetting between anode and electrolyte.

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Measurement of Anode Anisotropy by Micro X-Ray Computed Tomography

Rørvik

Lossius

2019

Light Metals 2019

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Micro X-ray Computed Tomography (CT) is an instrumental method for recording inner structure 3D images without damaging the observed volume. A methodology has been developed by SINTEF for CT of carbonaceous materials, yielding detailed structural views and quantification of the pore, void and grain distribution within volumes of 10 mm to 130 mm diameter. Example results are shown from a study of anode anisotropy. A series of vertical cores from a prebaked anode was analysed, selected due to clear difference in top, middle and bottom level structure. The CT data was calibrated and connected to the physical position in the anode. The data was analysed with various methods that quantify the degree of anisotropy. The analysis show that the anodes have a 10-15 cm wide zone of high anisotropy, while the top and bottom of the anode are more isotropic. Some possible reasons for mid-height anisotropy are discussed.

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Characterization of Prebake Anodes by Micro X-ray Computed Tomography

Cited by 7 publications

References 6 publications

Investigation of Molten Metal Infiltration into Micropore Carbon Refractory Materials Using X-ray Computed Tomography

Investigation of Molten Metal Infiltration into Micropore Carbon Refractory Materials Using X-ray Computed Tomography

Comparing Anodic Bubble Behavior of Anodes from Anisotropic and Isotropic Cokes in Laboratory Scale Aluminum Electrolysis Cells

Measurement of Anode Anisotropy by Micro X-Ray Computed Tomography

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