Structural properties of Mn-substituted hercynite

Jastrzębska, Ilona; Bodnar, Wiktor; Witte, Kerstin; Burkel, E.; Stoch, P.; Szczerba, Jacek

doi:10.1515/nuka-2017-0013

Cited by 9 publications

(3 citation statements)

References 24 publications

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“…Typically for spinels is the broad contribution of Fe 2+ consisting of three subcomponents. This is explainable by the quadrupole splitting distribution due to different nearest-neighbor contributions next to the Fe 2+ -probe nuclei as observed previously in literature [40][41][42][43][44][45]. At 0.91 mm/s a characteristic isomer shift for the Fe 2+ -tetrahedral coordination is visible [46].…”

Section: Mössbauer Spectroscopysupporting

confidence: 77%

Proposition of a Thermogravimetric Method to Measure the Ferrous Iron Content in Metallurgical-Grade Chromite

Sommerfeld

Friedrich

2022

Minerals

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The oxidation state of iron in minerals is an important part of analysis. Especially for minerals used as a raw material for metallurgical processes, the oxidation state has a significant impact on the process. One crucial impact is the varying carbon requirement in smelting furnaces, which can be significantly different if the oxidation state is not assessed correctly. Compared to methods usually used to determine the oxidation state, a relatively simple and fast thermogravimetric method is proposed in this article. As a sample, a detailed analyzed chromite sample from Turkey is used. Bulk chemical analysis, Raman spectroscopy, X-ray diffraction, and QEMSCAN® are used to determine the preconditions of the sample. Mössbauer spectroscopy is used as a reference method to determine the oxidation state of iron in the sample. Uncertified wet chemical methods are investigated as well in this paper and the results are compared with the reference measurement. Using a thermochemical simulation tool, parameters for the thermogravimetric method are investigated and the limitation of this method is examined. The mean ferrous ratio in the sample determined by the proposed method is 75.205%, which is only slightly lower than the ferrous ratio of 76% determined by Mössbauer spectroscopy.

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Section: Mössbauer Spectroscopysupporting

confidence: 77%

Proposition of a Thermogravimetric Method to Measure the Ferrous Iron Content in Metallurgical-Grade Chromite

Sommerfeld

Friedrich

2022

Minerals

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“…The material taken for the image analysis was ceramic oxide material, produced via the arc melting technique [ 25 ] that was previously used successfully for the synthesis of numerous high-temperature spinel compounds [ 26 , 27 , 28 ] and high-temperature materials [ 29 , 30 ]. The starting materials were analytical grade powders of Fe 2 O 3 , CuO, and Al 2 O 3 (Sigma Aldrich) mixed in the molar proportions 0.25:0.5:1 and homogenized in a ball mill.…”

Section: Methodsmentioning

confidence: 99%

Traditional vs. Automated Computer Image Analysis—A Comparative Assessment of Use for Analysis of Digital SEM Images of High-Temperature Ceramic Material

Jastrzębska

Piwowarczyk

2023

Materials

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Image analysis is a powerful tool that can be applied in scientific research, industry, and everyday life, but still, there is more room to use it in materials science. The interdisciplinary cooperation between materials scientists and computer scientists can unlock the potential of digital image analysis. Traditional image analysis used in materials science, manual or computer-aided, permits for the quantitative assessment of the coexisting components at the cross-sections, based on stereological law. However, currently used cutting-edge tools for computer image analysis can greatly speed up the process of microstructure analysis, e.g., via simultaneous extraction of quantitative data of all phases in an SEM image. The dedicated digital image processing software Aphelion was applied to develop an algorithm for the automated image analysis of multi-phase high-temperature ceramic material. The algorithm recognizes each phase and simultaneously calculates its quantity. In this work, we compare the traditional stereology-based methods of image analysis (linear and planimetry) to the automated method using a developed algorithm. The analysis was performed on a digital SEM microstructural image of high-temperature ceramic material from the Cu-Al-Fe-O system, containing four different phase components. The results show the good agreement of data obtained by classical stereology-based methods and the developed automated method. This presents an opportunity for the fast extraction of both qualitative and quantitative from the SEM images.

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“…Spinel phase MgAl 2 O 4 showed relatively high resistance to Pb-rich copper slag at high temperatures, as only about 0.7% of Pb and 0.6% of Cu were detected in the spinel grains at 1100 • C, while at 1400 • C only Cu was observed at the level of 1.3%, and no Pb was detected. Spinel accepted above 5% of Fe at 1400 • C (and 0.7% at 1100 • C), and this behavior is characteristic for spinel structure, which tolerates ions with radii 40-80 pm (ferrous ions: r Fe2+,IV = 61.5 pm, r Fe2+,VI = 74 pm; ferric ions: r Fe3+,IV = 49 pm, r Fe3+,VI = 64.5 pm) [67][68][69][70][71]. Arsenic ions were not registered in any analyzed region.…”

Section: Microstructure Analysis Of the Raw Material-slag Mixtures Af...mentioning

confidence: 99%

Corrosion Resistance of MgO and Cr2O3-Based Refractory Raw Materials to PbO-Rich Cu Slag Determined by Hot-Stage Microscopy and Pellet Corrosion Test

et al. 2022

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Chemical resistance of commercial refractory raw materials against Cu slag is critical to consider them as candidates for the production of refractories used in Cu metallurgy. In this study, we show the comparative results for the corrosion resistance of four commercial refractory raw materials—magnesia chromite co-clinkers FMC 45 and FMC 57, PAK, and fused spinel SP AM 70—against aggressive, low-melting PbO-rich Cu slag (Z1) determined by hot-stage microscopy (up to 1450 °C) and pellet test (1100 and 1400 °C). Samples were characterized after the pellet test by XRD, SEM/EDS, and examination of their physicochemical properties to explore the corrosion reactions and then assess comparatively their chemical resistance. Since many works have focused on corrosion resistance of refractory products, the individual refractory raw materials have not been investigated so far. In this work, we show that magnesia chromite co-clinker FMC 45 exhibits the most beneficial properties considering its application in the production of refractories for the Cu industry. Forsterite (Mg2SiO4) and güggenite (Cu2MgO3) solid solutions constitute corrosion products in FMC 45, and its mixture with slag shows moderate dimensional stability at high temperatures. On the other hand, the fused spinel SP AM 70 is the least resistant to PbO-rich Cu slag (Z1); it starts to sinter at 970 °C, followed by a fast 8%-shrinkage caused by the formation of güggenite solid solution in significant amounts.

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Structural properties of Mn-substituted hercynite

Cited by 9 publications

References 24 publications

Proposition of a Thermogravimetric Method to Measure the Ferrous Iron Content in Metallurgical-Grade Chromite

Proposition of a Thermogravimetric Method to Measure the Ferrous Iron Content in Metallurgical-Grade Chromite

Traditional vs. Automated Computer Image Analysis—A Comparative Assessment of Use for Analysis of Digital SEM Images of High-Temperature Ceramic Material

Corrosion Resistance of MgO and Cr2O3-Based Refractory Raw Materials to PbO-Rich Cu Slag Determined by Hot-Stage Microscopy and Pellet Corrosion Test

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