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Structural properties of Mn-substituted hercynite

Jastrzębska I., Bodnar W., Witte K., Burkel E., Stoch P., Szczerba J.

Nukleonika

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2017

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Vol. 62, No. 2

95--100

EN

In this work spinel series with the general formula Fe1–xMnxAl2O4 (where x = 0, 0.3, 0.5 and 0.7) were synthesized and characterized with respect to their structure and microstructure. X-ray diffractometry (XRD) was used to identify the phase composition that revealed a single phase spinel material. Rietveld refinements of the XRD patterns were carried out in order to determine the lattice and oxygen positional parameters of the spinel compounds. Mössbauer effect measurements were performed at room temperature to determine the local chemical environment of the Fe ions, their valences, and degrees of spinels inversion. It was shown that an increase in the Mn content led to a decrease in the ratio of Fe2+ to Fe3+. The results obtained from Mössbauer spectroscopy (MS) were used to establish the chemical formulas of the synthesized spinels. Finally, the microstructure that was observed using scanning electron microscopy (SEM) showed a compact microstructure with an octahedral crystal habit.

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Crystal structure and Mössbauer study of FeAl2O4

Jastrzębska I., Szczerba J., Stoch P., Błachowski A., Ruebenbauer K., Prorok R., Śnieżek E.

Nukleonika

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2015

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Vol. 60, No. 1

47--49

EN

In this work the synthesis of hercynite from Fe2O3 and Al2O3 powders was carried out by arc-melting method under the protective argon atmosphere. The obtained material was characterized with the use of powder X-ray diffractometry (XRD) and Mössbauer spectroscopy (MS). A Mössbauer effect in hercynite obtained by the arc-melting method indicated the cations distribution in the spinel structure among the tetrahedral and octahedral interstices. The presence of Fe2+ ions was detected in both tetrahedral and octahedral sites while Fe3+ ions occupied only the octahedral interstices. The approximate formula of the obtained iron-aluminate spinel was as follows (Fe2+ 0.77Al3+0.23)(Fe3+0.07Fe2+0.05Al0.88)2O4.

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Synteza hercynitu (FeAl2O4)

Szczerba J., Stoch P., Jabłońska A., Guzdek P.

Materiały Ceramiczne

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2005

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R. 57, nr 1

38-41

PL

Hercynit (FeAI2O4), minerał z grupy spineli, znajduje ostatnio zastosowanie jako składnik poprawiający właściwości materiałów magnezytowo-spinelowych dla przemysłu cementowego, szczególnie pracujących w strefie spiekania pieca obrotowego. Przedstawiono rezultaty badań nad syntezą hercynitu drogą topienia mieszaniny FeO2O3 i AI2O3 w piecu łukowym. Stwierdzono, że w strukturze otrzymanego hercynitu część żelaza zachowuje postać Fe3+, zastępując Al3+ w pozycjach teteraedrycznych. Otrzymany hercynit ma wzór Fe"(Fe'''O,5AI1,5)O4.

EN

Spinel group mineral, hercynite FeAI2O4, is used as a component improving the properties of the MgO refractories during they work in sintering zone of rotary kilns in cement industry. Synthesis of hercynite, by the melting Fe2O3 and AI2O3 mixture in the arc furnace, has been studied. Behavior of Fe2O3 during synthesis was investigated using Mossbauer spectroscopy. It has been established that a part of the iron persists in the hercynite structure as Fe3+, substituting Al3+ in tetrahedral position. Hercynite obtained has the formula Fe-"(Fe'"0.5AI1.5)O4.