The Preparation of Rare Earth Metals

Spedding, F. H.; Daane, A.H.

doi:10.2172/4393111

Cited by 7 publications

(9 citation statements)

References 4 publications

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“…In the case of UH3 (c)^Abraham and Flotow [44] and Spedding [45] measured the heat of formation of UH3 calorimetrically ; their data were confirmed by decomposition pressure data. The value for Zrll2 is calculated by extrapolation from the data in [26].…”

Section: Heavy Metal Hydridesmentioning

confidence: 81%

Preliminary report on the thermodynamic properties of selected light-element and some related compounds:

1962

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This is the seventh semi-annual report on the current experimental, theoretical, and evaluative program, at the National Bureau of Standards, on the thermodynamic properties of selected light-element compounds of primary interest in high-temperature research. In this connection the chemical elements principally involved are H, Li, Be, B, C, N, 0, F, At, Cl, and Zr, with more secondary interest in the compounds of Mg, Si, K, Ti, Br, I, W, Hg, and Pb. The emphasis in the NBS work has been on the simpler compounds of these elements.This report includes some recent NBS measurements under the program: The heat of formation of nitronium perchlorate, and the high-temperature heat capacity of aluminum carbide. As discussed in the report, precise measurements are essentially completed on the heat of combustion of aluminum in fluorine and on the low-temperature heat capacities and absolute entropies of LiH, and LiAlH^; however, these data are not yet presented, pending the resolution of small discrepancies needed to put the results on a final basis. Tables of thermodynamic functions are given for four gases omitted from earlier reports (H 2 > 02> H , and electron gas), and, on the basis of improved data, for the condensed phases of two substances (BeF 2 and At^C^) . A contribution from those areas in which elaborate apparatus development is still progressing is a description in the report of a new fast-opening large-aperture shutter for high-speed photography. This development will be important in the study of combustions at very high temperatures and pressures.Also included are several up-to-date literature surveys in the field.One describes recent additions to the literature on the chemistry of numerous light-element compounds. A second describes alloys and intermetallic compounds of aluminum and beryllium with titajaium and zirconium; while a third survey covers low-temperature heat capacities aud entropies of various substances, particularly the oxides of eight light elements. The fourth report is a comprehensive and critical assembly of the available values for the heats of formation of a large number of compounds. IntroductionNitronium perchlorate is a v;hite, crystalline material, stable at temperatures up to 120°C. It is extremely hygroscopic, reacting rapidly with water to form nitric and perchloric acids. Aqueous solutions of potassium hydroxide were used in this investigation, as the potassium salts of the acids provided more suitable reference substances. The heats of solution of KN0_(c) and KClO/c) in KOH(aq) were also determined. Constants and Conversion FactorsThe results of this investigation are given in joules and calories, with 1 cal = 4*1840 joules. All weights are corrected to vacuum. The molecular weights are calculated from the 1957 International Table of Atomic Weights [l]. For N02C10/(c) an estimated heat capacity of 36 cal/deg mole was used; other auxiliary data were taken where possible from [2].3. MaterialsThe KNO^(c) and KC10/(c) were reagent-grade materials, dried at 120°...

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Section: Heavy Metal Hydridesmentioning

confidence: 81%

Preliminary report on the thermodynamic properties of selected light-element and some related compounds:

1962

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“…So, Spedding F. and A. Dahan [4] for the electrochemical production of rare earth metals used molten fluoride system (REM-lithium fluoride-alkali metal fluoride). As for Iosisuke H. [5], he proposed the fluoride-oxide electrolyte for production of high melting point REM (Gd, Sm, Dy, Y).…”

Section: Introductionmentioning

confidence: 99%

The Electroreduction of Gadolinium and Dysprosium Ions in Equimolar NaCl-KCl Melt

Kushkhov¹,

Uzdenova²,

Saleh³

et al. 2013

AJAC

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The mechanism of rare earth metals (Gd and Dy) chloride complexes electroreduction on the tungsten electrode in equimolar NaCl-KCl melt at 973 K has been studied by linear and cyclic voltammetry. Some kinetic parameters of processes were calculated. It was shown that the tungsten electrode was indifferent to gadolinium and dysprosium which were reduced on the surface. We found that the discharge mechanism of gadolinium and dysprosium chloride complexes was described by three-electron step when the steady-state conditions of polarization were limited by the mass transfer stage. The conditions of nonstationary polarization made the slowness of the charge transfer stage. The diffusion coefficient of gadolinium and dysprosium ions was calculated, the diffusion coefficient of ions was (0.9, and for ions, it was (1.60 ± 0.2) × 10 −5 сm 2 ·s DyCl −

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“…The measured enthalpy of the sample, the reproducibility, the calculated enthalpy from empirical equations based on the observed enthalpy as a function of temperature and the devi ation of the observed enthalpy from the calculated enthalpy at each temperature are given in Table 3» The calculated The observed enthalpy for lanthanum is shown as a func tion of temperature from 0° to 1100°C in Figure 10 The entropy is obtained utilizing the following integra tion: The transition temperature for the hcp-fcc transition was taken as 310°C based on this work and on that of Barson et al (1957) who studied the thermal expansion of some of the rare earths. The fcc-bcc transition was reported by Spedding and Daane (1954) to be 868®C from thermal analysis studies, and verified by Spedding ,gt ai.…”

Section: Aluminummentioning

confidence: 67%

“…( ) 1954) and Spedding and Powell (1954), were used in this laboratory to separate the rare earths from their ores and from each other. The lanthanum and praseodymium samples, weighing 13.3877 and 21.3845 grams respectively, were prepared by metalothermic reduction of the anhydrous fluorides with calcium as described by Daane (1954, 1956).…”

Section: Methodsmentioning

confidence: 99%

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High temperature thermodynamic properties of some of the rare earths

Berg

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The Preparation of Rare Earth Metals

Cited by 7 publications

References 4 publications

Preliminary report on the thermodynamic properties of selected light-element and some related compounds:

Preliminary report on the thermodynamic properties of selected light-element and some related compounds:

The Electroreduction of Gadolinium and Dysprosium Ions in Equimolar NaCl-KCl Melt

High temperature thermodynamic properties of some of the rare earths

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