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57Fe Mössbauer effect studies of ErFe11Ti and ErFe11TiH compounds

100%

Gaczyński P. , Tereshina I. , Rusakov V. , Nikitin S. , Drulis H.

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tom Vol. 48,suppl.1

25-29

EN

Ferromagnetic compounds ErFe11TiHx (x = 0, 1) have been investigated by 57Fe Mössbauer spectroscopy in the temperature range 20–300 K. Mössbauer spectra were analyzed in terms of a model which takes into account the local environment of Fe atoms on three crystallographic sites (8f, 8j and 8i) and an influence of the random distribution of titanium on the 8i site. The 14 sextets with different intensities have been considered. The temperature dependencies of hyperfine interaction parameters and subspectra contributions were derived from experimental spectra. The hyperfine fields and the isomer shift increasing upon hydrogenation are discussed in terms of the hydrogen-induced Wigner-Seitz unit cell expansion and the s-electrons transfer from Fe atoms to the adjacent hydrogen atoms.

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Process mineralogy of Bayan Obo rare earth ore by MLA

100%

Xu C. , Chi R. a. , Zhang Y. , Zhong C. , Ruan Y. , Lyu R. , Zhou F.

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tom Vol. 56, iss. 4

737--745

EN

The maximum recovery of rare earth resource from the Bayan Obo ore deposit is a difficult task, especially without the sufficient data of mineralogy. In this paper the mineralogy of Bayan Obo ore deposit by comprehensively research with the application of mineral liberation analyzer (MLA) is reported. The MLA was applied to quantitatively analyze the complicated element/mineral compositions, the REE occurrence, the size distribution and the degree of liberation of the Bayan Obo ore. Mineralogical analysis of the rare earth ore has shown that REEs are present mainly as bastnaesite and monazite-(Ce) to a small extent as parisite-(Ce). 5.85% of the REEs, 34.99% of iron and 0.12% of niobium occur in the ore sample. There are 76.99% of iron occurred in hematite and the remaining iron is mainly distributed in magnetite and goethite. The degree of liberation of bastnaesite and monazite(Ce) was 79.65% and 75.67% respectively when the grinding fineness was 83.57% passing 75 μm sieves. Un-liberated or partly liberated rare earth minerals are associated closely mainly with other rare earth minerals and gangues. These theoretical data could be employed to further comprehensively utilize the rare earth ore.

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Crystal Structure of the New Ternary Th2Ni17-Type Related Compounds in the R-Mn-Al Systems (R=Gd, Tb, Dy, Ho, Er)

88%

Kotur B. , Palasyuk A. M.

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tom Vol. 75, nr 5

633--637

EN

New hexagonal ternary phases R2-yMnzMnxAl17-x have been obtained in the Mn-rich regions of the R-Mn-Al (R = Gd, Tb, Dy, Ho, Er) systems: Gd2-yMnxAl17-x (0_y_0.15, 13.0 _x_ 15.1); Tb2-yMnxAl17-x (0_ y_0.23, 13.2_x_15.2); Dy2-yMnxAl17-x (0_y<~0.2, 11.9_x _14.6); Ho2-yMnxAl17-x (0_y<~0.2, 11.5_x_14.2) and Er2-yMnzMnxAl17-x (0_y_0.27, 0_ z_0.54, 11.3_x_14.1). Th2Ni17-type of structure occurs in alloys with the content of R = 10.5 at.% (ideal R2X17 stoichiometry). When R < 10.5 at.%, two ways of structure constitution are possible: i) formation of the Th2Ni17- type structure with defective 2(b) atomic position (solid solution of subtraction); ii) formation of the Th2Ni17-related type structure with the substitution of part of R atoms by the Mn-Mn pairs (solid solution of multiple substitution).

4

Effect of Fe Content on the Mechanical Properties and Thermal Conductivity of the Al-RE Alloys

88%

Yoo H.-S. , Kim Y.-H. , Son H.-T.

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tom Vol. 65, iss. 3

1029--1033

EN

In this study, we investigated the effect of Fe addition (0, 0.25, 0.50 and 0.75 wt.%) on the microstructure, mechanical properties and electrical conductivity of as-cast and as-extruded Al-RE alloys. As the Fe element increased by 0 and 0.75wt.%, the phase fraction increased to 5.05, 5.76, 7.14 and 7.38 %. The increased intermetallic compound increased the driving force for recrystallization and grain refinement. The electrical conductivity of Al-1.0 wt.%RE alloy with Fe addition decreased to 60.29, 60.15, 59.58 and 59.13 % IACS. With an increase in the Fe content from 0 to 0.75 wt.% the ultimate tensile strength (UTS) of the alloy increased from 74.3 to 77.5 MPa. As the mechanical properties increase compared to the reduction of the electrical conductivity due to Fe element addition, it is considered to be suitable for fields requiring high electrical conductivity and strength.

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Tlenkowe przewodniki superjonowe bivox domieszkowane pierwiastkami ziem rzadkich (La, Pr).

75%

Paściak G. , Chmielowiec J. , Bujło P.

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tom Vol. 44, nr 18

122-127

PL

Materiały z rodziny B1VOX (ang. Bismuth Vanadium Oxide) charakteryzują się dużą przewodnością jonową w stosunkowo niskich temperaturach i dlatego są potencjalnymi kandydatami na materiał elektrolityczny w urządzeniach elektrochemicznych takich jak: ogniwa paliwowe IT-SOFC (Intermediate Temperaturę Solid Oxide Fuel Celi) oraz pompy, separatory i czujniki tlenu. Stosując dodatki podstawiające atomy Bi i V w strukturze Bi4V2O11 można -stabilizować poszczególne odmiany polimorficzne materiału, a także modyfikować jego przewodność. Publikacja przedstawia badania autorów dotyczące wpływu dodatków pierwiastków ziem rzadkich -La i Pr na stabilność termodynamiczną i przewodność elektrolitu Bi4V2O11.

EN

BIVOX (Bismuth Vanadium Oxide) family materials are characterized by high ionic conductivity at relatively low temperature that's why are potential candidates for electrolytic materials used in electrochemical devices as: IT-SOFC (Intermediate Temperature Solid Oxide, Fuel Cell), oxygen pumps, separators and sensors. Applying additives, which substitute Bi and V atoms in the Bi4V2O11structure, one can stabilize individual polymorphic modifications as well as modify theirs conductivity. Present paper presents description of research concerning investigations of the influence of additives - rare-earth elements as La and Pr - on thermodynamic stability and ionic conductivity of Bi4 V2 O11 electrolyte.

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Structural and Mössbauer effect studies of Dy(Fe0.4Co0.6-x Alx)2 intermetallics

75%

Stoch P. , Pszczoła J. , Suwalski J. , Pańta A.

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tom Vol. 48,suppl.1

75-77

EN

The magnetic hyperfine fields observed at the 57Fe nuclei (77 K) in the Dy(Mn1-xFex)2 and Dy(Fe1-xCox)2 intermetallics form a Slater-Pauling curve. In order to study the effect of cobalt atoms on crystal structure and hyperfine interactions, the new Co/Al substituted series Dy(Fe0.4Co0.6-xAlx)2 was prepared and data of X-ray powder analysis are presented (300 K). From the 57Fe Mössbauer measurements at 77 K the hyperfine parameters were obtained. The magnetic hyperfine fields form a branch of the Slater-Pauling curve.

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Mineralogical characteristic and beneficiation evaluation of rare earth carbonate wall rock

75%

Gao C. , Yan G. , Wang H. , Luo H. , Zhang L. , Yang H. , Xu J.

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tom Vol. 59, iss. 1

art. no. 161300

EN

In order to rationalize the development and utilization of the wall rock discarded during rare earth mining, chemical analysis, inductively coupled plasma-atomic emission spectroscopy, X-ray diffraction analysis, artificial panning, optical microscope analysis, mineral liberation analysis and energy-dispersive spectroscopy were used to study the process mineralogy of the wall rock. The results show that the main useful elements in the rare earth wall rock were iron, light rare earth elements, fluorine and niobium. Iron was mainly occurrence as magnetic iron in magnetite, rare earth elements in bastnaesite and monazite, fluorine as a independent mineral in fluorite and niobium in columbite. The main useful minerals were finely disseminated, with magnetite (48.16%), bastnaesite (49.04%), monazite (42.18%), fluorite (39.30%) and columbite (63.26%) distributed in -0.030 mm particle size. The useful minerals were evaluated separately for beneficiation based on the process mineralogical characteristics of the rare earth wall rock, and the results showed that magnetite, rare earth and fluorite resources could be effectively recovered using magnetic separation, flotation, gravity concentration and leaching enrichment methods. The sequential recovery of iron, rare earth, fluorine and niobium elements produces iron concentrate (65.40% TFe at recovery of 38.03%), rare earth concentrate (50.66% REE at recovery of 62.73%), fluorite concentrate (95.23% CaF2 at recovery of 40.34%) and niobium iron ore concentrate (1.63% Nb2O5 at recovery of 5.56%). This study provides recommendations for the rational development and utilization of rare earth wall rock and provides reasonable levels of recovery predictions.

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Wpływ zawartości Sm na właściwości magnesów Sm-Fe-N wytwarzanych metodą HDDR

51%

Kaszuwara W. , Leonowicz M.

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tom T. 21, nr 3-4

143-154

PL

Metodę HDDR (hydrogenation, disproportionation, desorption, recombination) stosuje się do otrzymywania drobnokrystalicznych proszków materiałów typu RE-M (metal ziem rzadkich-metal przejściowy) o właściwościach magnetycznie twardych. W pracy badano wpływ zawartości Sm na właściwości magnesów Sm-Fe-N uzyskiwanych metodą HDDR, z uwzględnieniem zmian temperatury rekombinacji, tj. najważniejszego z parametrów tego procesu. Opisano wzajemny wpływ obu wymienionych czynników na strukturę fazową i właściwości magnesów.

EN

Hydrogenation disproportionation desorption recombination (HDDR) method has been used for the processing of rare earth-transition metal (RE-M) powders with hard magnetic properties. In this study the effect of Sm content on the properties of HDDR processed Sm-Fe-N magnets versus recombination temperature has been analysed. The influence of both these variables on the phase structure and magnetic properties is presented.

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Radioactive mineralization in pegmatites, of Dara-Um Swassi, Area North Eastern Desert, Egypt

51%

Shalaby M. H. , Osman A. M. , Ali M. M. , Ahamed F. Y. , Ali B. H.

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