Thermodynamic Properties of Lanthanide Fluorides and Chlorides in the Gaseous and Condensed States

Chervonnyi, A. D.

doi:10.1016/b978-0-444-54316-5.00002-8

Cited by 5 publications

(14 citation statements)

References 375 publications

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“…The quantum-chemical calculations performed by Su et al 14 for YbX using the unrestricted coupled cluster singles and doubles method with perturbative treatment of triple excitations (UCCSD(T)) lead to much higher values as compared to the experimental ones. 12 Recently Smirnov and Solomonik 15 applied the composite quantum-chemical approach including the R/RCCSD(T) method and obtained the atomization energies for the LaX, YbX, and LuX molecules, which are closer to those recommended in ref 12. Thus, the available information on the atomization energies of the LnX molecules is contradictory and it does not allow a reliable estimation of the energies of LnBr and LnI molecules, which were not experimentally studied so far.…”

Section: ■ Introductionmentioning

confidence: 57%

“…26 the statistical weight of the main electronic state of the YbBr and YbI molecules was assumed to correspond to that of Yb + ion (J = 1/2); 27 the contribution of exited electronic states to the reduced Gibbs energies was assumed to be equal to that of Yb + (5 J•mol −1 •K −1 for the temperature range of (298 to 1500) K). 12 Using the above functions those of the SmBr, EuBr, SmI, and EuI molecules were estimated by a comparative method. 28 Namely, we transferred the SmCl/EuCl/YbCl ratio 12 for reduced Gibbs energies to corresponding bromides and iodides.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

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Atomization Energies of LnX Molecules (Ln = Sm, Eu, and Yb; X = Cl, Br, and I)

et al. 2014

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The gas phase equilibria Ba + LnX = BaX + Ln (Ln = Sm, Eu, Yb; X = Cl, Br, I) were investigated by Knudsen effusion mass spectrometry using a low energy of ionizing electrons to avoid fragmentation processes. The BaX molecules were used as references with well-established bond energies. The atomization enthalpies Δat H 0 ° of the LnX molecules were determined to be 427 ± 9 (SmCl), 409 ± 9 (EuCl), 366 ± 9 (YbCl), 360 ± 10 (SmBr), 356 ± 13 (EuBr), 316 ± 9 (YbBr), 317 ± 10 (SmI), 293 ± 10 (EuI), and 283 ± 10 (YbI) kJ·mol–1.

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Section: ■ Introductionmentioning

confidence: 57%

Section: ■ Results and Discussionmentioning

confidence: 99%

Atomization Energies of LnX Molecules (Ln = Sm, Eu, and Yb; X = Cl, Br, and I)

et al. 2014

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“…3 (2) , it is likely that Cr is chlorinated in a SmCl 3 -contaning molten salt at 1100 K as follows: Figure 4 shows the vapor pressures of the metal chlorides calculated using thermodynamic data. 27,30,31) The vapor pressure of CrCl 2 is 8.0 × 10 −4 atm at 1100 K, 31) which is much lower than that of TiCl 4 and FeCl x . Consequently, any CrCl 2 generated may accumulate in the molten salt when chlorinated at around 1100 K.…”

Section: Chlorination Of Off-grade Spongementioning

confidence: 99%

“…Therefore, the Gibbs energy change of solid/liquid transformation has to be considered. According to the literature, 30) the melting point of SmCl 2 is 1132 K, and its Gibbs energy of fusion has small positive value at 1100 K: (2) = −137 kJ at 1100 K Consequently, even in a molten salt system, Ti in scrap is po- Fig. 3 Chemical potential diagrams at 1100 K for the (a) Ti-Sm-Cl system, 17,27) (b) Fe-Sm-Cl system, 17,27,28) (c) Ni-Sm-Cl system, 27,29) and (d) Cr-Sm-Cl system.…”

Section: Chlorination Of Off-grade Spongementioning

confidence: 99%

Chlorination-Volatilization Behavior of Titanium Metal Scraps during Recycling Using Reaction-Mediating Molten Salt

2016

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In order to develop an ef cient and environmentally friendly process for recycling both titanium scrap and FeCl x (x = 2, 3) waste, the chlorination-volatilization of titanium metal scraps utilizing a MgCl 2 -SmCl 3 reaction-mediating molten salt was examined. After the thermodynamic analyses on the chlorination behavior of representative elements such as the alloying elements and oxygen, fundamental experiments were carried out at 1100 K by reacting off-grade Ti sponge, Ti-6Al-4V alloy rod, and Ti rod with MgCl 2 -SmCl 3 molten salt. The results indicated that TiCl 4 could be effectively produced and volatilized from off-grade sponge and Ti-6Al-4V alloy. It was also con rmed that Fe and Ni in the Ti scrap remain in the molten salt as metal, whereas the Al and V in Ti alloy are chlorinated by SmCl 3 and their chlorides volatilized. Oxygen introduced into the reaction system was found to form TiOCl in the molten salt, and therefore does not consume the SmCl 3 mediator in the molten salt. These ndings con rm that chlorination using a reaction-mediating molten salt is an effective means of recycling both titanium scrap and FeCl x waste.

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“…Figure 4 shows the chemical potentials of chlorine, Á® Cl 2 (¼ RT ln p Cl 2 ), corresponding to Ln/LnCl 2 and LnCl 2 /LnCl 3 equilibria at 1100 K, which were calculated using thermodynamic data available in the literature. 30,41) In Fig. 4 by FeCl x .…”

Section: Thermodynamics Of Lanthanoid Chloridesmentioning

confidence: 99%

Reaction-Mediator-Based Chlorination for the Recycling of Titanium Metal Scrap Utilizing Chloride Waste

2015

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In this study, a novel chlorination technique for metallic titanium (Ti) was devised in order to establish a recycling process that uses both Ti metal scrap and iron chloride (FeCl x ) waste, and its feasibility was demonstrated. Direct reaction between Ti and FeCl x has drawbacks such as slow kinetics of Ti chlorination and high volatilization of FeCl x . To overcome these, the authors proposed a chlorination technique utilizing a reaction mediator in molten salt. Based on thermodynamic analyses of lanthanoid chlorides, some fundamental experiments were carried out with samarium trichloride (SmCl 3 ) as a reaction mediator. It was experimentally demonstrated that SmCl 3 in molten magnesium chloride (MgCl 2 ) can smoothly chlorinate Ti metal into gaseous titanium tetrachloride (TiCl 4 ), and the by-product SmCl 2 in the molten salt can be regenerated into SmCl 3 by FeCl 2 . Thus, SmCl 3 in a molten salt works efficiently as a reaction mediator, and the newly proposed chlorination technique has the potential to make the Ti recycling process more efficient and environmentally friendly.

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Thermodynamic Properties of Lanthanide Fluorides and Chlorides in the Gaseous and Condensed States

Cited by 5 publications

References 375 publications

Atomization Energies of LnX Molecules (Ln = Sm, Eu, and Yb; X = Cl, Br, and I)

Atomization Energies of LnX Molecules (Ln = Sm, Eu, and Yb; X = Cl, Br, and I)

Chlorination-Volatilization Behavior of Titanium Metal Scraps during Recycling Using Reaction-Mediating Molten Salt

Reaction-Mediator-Based Chlorination for the Recycling of Titanium Metal Scrap Utilizing Chloride Waste

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