Thermodynamics of solid phases containing rare earth oxides

Navrotsky, Alexandra; Lee, Wingyee; Mielewczyk‐Gryń, Aleksandra; Ushakov, Sergey V.; Anderko, Andrzej; Wu, Haohan; Riman, Richard E.

doi:10.1016/j.jct.2015.04.008

Cited by 82 publications

(59 citation statements)

References 142 publications

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“…For a detailed overview of the available calorimetric data for REEbearing solids, readers are referred to the recent review of Navrotsky et al (2015). Among the studies reported, most are devoted to synthetic phases important for industrial applications but of little relevance to hydrothermal processes.…”

Section: Thermochemistry and Solubility Of Hydrothermally Formed Ree-mentioning

confidence: 99%

Hydrothermal transport, deposition, and fractionation of the REE: Experimental data and thermodynamic calculations

et al. 2016

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For many years, our understanding of the behavior of the REE in hydrothermal systems was based on semiempirical estimates involving extrapolation of thermodynamic data obtained at 25°C (Haas et al., 1995;Wood, 1990a). Since then, a substantial body of experimental data has accumulated on the stability of aqueous complexes of the REE. These data have shown that some of the predictions of Haas et al. (1995) are accurate, but others may be in error by several orders of magnitude. However, application of the data in modeling hydrothermal transport and deposition of the REE has been severely hampered by the lack of data on the thermodynamic properties of even the most common REE minerals. The discrepancies between the predictions of Haas et al. (1995) and experimental determinations of the thermodynamic properties of aqueous REE species, together with the paucity of data on the stability of REE minerals, raise serious questions about the reliability of some models that have been proposed for the hydrothermal mobility of these critical metals. In this contribution, we review a body of high-temperature experimental data collected over the past 15 years on the stability of REE aqueous species and minerals. Using this new thermodynamic dataset, we re-evaluate the mechanisms responsible for hydrothermal transport and deposition of the REE. We also discuss the mechanisms that can result in REE fractionation during their hydrothermal transport and deposition. Our calculations suggest that in hydrothermal solutions, the main REE transporting ligands are chloride and sulfate, whereas fluoride, carbonate, and phosphate likely play an important role as depositional ligands. In addition to crystallographic fractionation, which is based on the differing affinity of mineral structures for the REE, our models suggest that the REE can be fractionated hydrothermally due to the differences in the stability of the LREE and HREE as aqueous chloride complexes.

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Section: Thermochemistry and Solubility Of Hydrothermally Formed Ree-mentioning

confidence: 99%

Hydrothermal transport, deposition, and fractionation of the REE: Experimental data and thermodynamic calculations

et al. 2016

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“…This dataset comprises mineral data from Holland and Powell [55] and aqueous species from SUPCRT92 [36,57,63,64], with the recently updated internally consistent dataset of Miron et al [58] using the GEMSFITS code package [65]. Experimental data for REE chloride aqueous species were implemented using data from the study of Migdisov et al [35], the HCl dissociation constants of Tagirov et al [59], and the properties of REE(OH) 3 (s) compiled in the study of Navrotsky et al [56]. Data for aqueous REE carbonate and bicarbonate species were included using the theoretical predictions of Haas et al [36], which are currently the only available high temperature thermodynamic data for these species.…”

Section: Thermodynamic Dataset and Activity Modelsmentioning

confidence: 99%

“…Lastly, thermodynamic data for Lu(OH) 3 (s) are not available, as it was omitted in the Navrotsky et al [56] study. Cerium-, Dy-, Er-, and Tm(OH) 3 (s) thermodynamic data from the aforementioned study were derived from thermochemical data reported in Diakonov et al (1998) [76].…”

Section: Uncertainties and Assumptions Of The Modelmentioning

confidence: 99%

Rare Earth Elements in Mineral Deposits: Speciation in Hydrothermal Fluids and Partitioning in Calcite

Perry

Gysi

2018

Geofluids

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is properly cited.Studying the speciation and mineral-fluid partitioning of the rare earth elements (REE) allows us to delineate the key processes responsible for the formation of economic REE mineral deposits in natural systems. Hydrothermal REE-bearing calcite is typically hosted in carbonatites and alkaline rocks, such as the giant Bayan Obo REE deposit in China and potential REE deposits such as Bear Lodge, WY. The compositions of these hydrothermal veins yield valuable information regarding pressure ( ), temperature ( ), salinity, and other physicochemical conditions under which the REE can be fractionated and concentrated in crustal fluids. This study presents numerical simulation results of the speciation of REE in aqueous NaCl-H 2 O-CO 2 -bearing hydrothermal fluids and a new partitioning model between calcite and fluids at different --conditions. Results show that, in a high CO 2 and low salinity system, bicarbonate/carbonate are the main transporting ligands for the REE, but predominance shifts to chloride complexes in systems with high CO 2 and high salinity. Hydroxyl REE complexes may be important for the solubility and transport of the REE in alkaline fluids. These numerical predictions allow us to make quantitative interpretations of hydrothermal processes in REE mineral deposits, particularly in carbonatites, and show where future experimental work will be essential in improving our modeling capabilities for these ore-forming processes.

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“…However, the main concern that arises with the use of REOs as a part of biomedical applications is their relatively unknown effects on the physiological system and research needs to be carried out if these oxides are too toxic for use as biomaterials [20]. Sm 2 O 3 is one such REO having density 8.347 g/cc with high hardness Vickers (438 HV), high melting temperature (2335 • C), elastic modulus (183 GPa), Gibbs free energy (−1734.9 KJ·Mol −1 ) [21,22]. Sm 2 O 3 is an important rare earth oxide and its current scope lies in the field of solar cells, semiconductor gas, biochemical sensors, laser and photonic devices, precision guided weapons, and is also an active catalyst for CO hydrogenation [23].…”

mentioning

confidence: 99%

Significantly Enhancing the Ignition/Compression/Damping Response of Monolithic Magnesium by Addition of Sm2O3 Nanoparticles

Kujur

Mallick

Manakari

et al. 2017

Metals

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Abstract:The present study reports the development of Mg-Sm 2 O 3 nanocomposites as light-weight materials for weight critical applications targeted to reduce CO 2 emissions, particularly in the transportation sector. Mg-0.5, 1.0, and 1.5 vol % Sm 2 O 3 nanocomposites are synthesized using a powder metallurgy method incorporating hybrid microwave sintering and hot extrusion. The microstructural studies showed dispersed Sm 2 O 3 nanoparticles (NPs), refinement of grain size due to the presence of Sm 2 O 3 NPs, and presence of limited porosity. Microhardness and dimensional stability of pure Mg increased with the progressive addition of Sm 2 O 3 NPs. The addition of 1.5 vol % of Sm 2 O 3 NPs to the Mg matrix enhanced the ignition temperature by~69 • C. The ability of pure Mg to absorb vibration also progressively enhanced with the addition of Sm 2 O 3 NPs. The room temperature compressive strengths (CYS and UCS) of Mg-Sm 2 O 3 nanocomposites were found to be higher without having any adverse effect on ductility, leading to a significant increase in energy absorbed prior to compressive failure. Further, microstructural characteristics are correlated with the enhancement of various properties exhibited by nanocomposites.

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Thermodynamics of solid phases containing rare earth oxides

Abstract: This paper is dedicated to the memory of Lester R. Morss (1940-2014), a wonderful colleague and friend who contributed extensively to the thermodynamics, chemistry, and physics of lanthanides and actinides and to service to the Department of Energy.

Cited by 82 publications

References 142 publications

Hydrothermal transport, deposition, and fractionation of the REE: Experimental data and thermodynamic calculations

Hydrothermal transport, deposition, and fractionation of the REE: Experimental data and thermodynamic calculations

Rare Earth Elements in Mineral Deposits: Speciation in Hydrothermal Fluids and Partitioning in Calcite

Significantly Enhancing the Ignition/Compression/Damping Response of Monolithic Magnesium by Addition of Sm2O3 Nanoparticles

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