Thermodynamics of formation for zirconolite (CaZrTi2O7) from T = 298.15 K to T = 1500 K

Robert L. Putnam; Alexandra Navrotsky; Brian F. Woodfield; Juliana Boerio-Goates; Jennifer L. Shapiro

doi:10.1006/jcht.1998.0445

Thermodynamics of formation for zirconolite (CaZrTi₂O₇) from T = 298.15 K to T = 1500 K

Robert L. Putnam, Alexandra Navrotsky, Brian F. Woodfield, Juliana Boerio-Goates, Jennifer L. Shapiro

Research output: Contribution to journal › Article › peer-review

59 Scopus citations

Abstract

Zirconolite (CaZrTi₂O₇) has been proposed as a ceramic host for the long-term disposal of excess weapons-grade plutonium. Using high-temperature oxide-melt solution calorimetry, the standard molar enthalpy of formation at T = 298.15 K for zirconolite, Δ_fH^o_m = -(3713.7 ± 4.5) kJ·mol^-1, has been obtained. In combination with the third-law entropy Δ^{298.15 K}₀ S^o_m obtained by using adiabatic calorimetry on the same sample, the standard molar Gibbs free energy of formation at T = 298.15 K, Δ_fG^o_m = -(3514.5 ± 4.5) kJ·mol^-1, has also been obtained. The formation enthalpies, free energies, and third-law entropies Δ^T₀ S_m are reported from T = 298.15 K to T = 1500 K. Also reported for ZrTiO₄, a compound of interest with respect to the (CaO, TiO₂, ZrO₂) phase diagram containing zirconolite, are the first estimates of the standard molar enthalpy and Gibbs free energy of formation, Δ_fH^o_m(ZrTiO₄) = -(2048.7 ± 5.0) kJ·mol^-1, and Δ_fG^o_m(ZrTiO₄) = -(1935.7 ± 5.0) kJ·mol^-1.

Original language	English (US)
Pages (from-to)	229-243
Number of pages	15
Journal	Journal of Chemical Thermodynamics
Volume	31
Issue number	2
DOIs	https://doi.org/10.1006/jcht.1998.0445
State	Published - Feb 1999
Externally published	Yes

Keywords

Calorimetry
Enthalpy of formation
Nuclear waste
Plutonium disposition
Thermodynamic properties
Zirconolite (CaZrTiO)

ASJC Scopus subject areas

Atomic and Molecular Physics, and Optics
General Materials Science
Physical and Theoretical Chemistry

Access to Document

10.1006/jcht.1998.0445

Cite this

@article{2e755f272d964c319b386fe8581dbc06,

title = "Thermodynamics of formation for zirconolite (CaZrTi2O7) from T = 298.15 K to T = 1500 K",

abstract = "Zirconolite (CaZrTi2O7) has been proposed as a ceramic host for the long-term disposal of excess weapons-grade plutonium. Using high-temperature oxide-melt solution calorimetry, the standard molar enthalpy of formation at T = 298.15 K for zirconolite, ΔfHom = -(3713.7 ± 4.5) kJ·mol-1, has been obtained. In combination with the third-law entropy Δ298.15 K0 Som obtained by using adiabatic calorimetry on the same sample, the standard molar Gibbs free energy of formation at T = 298.15 K, ΔfGom = -(3514.5 ± 4.5) kJ·mol-1, has also been obtained. The formation enthalpies, free energies, and third-law entropies ΔT0 Sm are reported from T = 298.15 K to T = 1500 K. Also reported for ZrTiO4, a compound of interest with respect to the (CaO, TiO2, ZrO2) phase diagram containing zirconolite, are the first estimates of the standard molar enthalpy and Gibbs free energy of formation, ΔfHom(ZrTiO4) = -(2048.7 ± 5.0) kJ·mol-1, and ΔfGom(ZrTiO4) = -(1935.7 ± 5.0) kJ·mol-1.",

keywords = "Calorimetry, Enthalpy of formation, Nuclear waste, Plutonium disposition, Thermodynamic properties, Zirconolite (CaZrTiO)",

author = "Putnam, {Robert L.} and Alexandra Navrotsky and Woodfield, {Brian F.} and Juliana Boerio-Goates and Shapiro, {Jennifer L.}",

note = "Funding Information: We wish to acknowledge B. Ebbinghaus for the Rietveld refinement of the lattice parameters for zirconolite, R. VanKonynenburg at Lawrence Livermore National Laboratory for synthesis of the zirconolite sample, and D. Dooley for her work in our laboratory on TiO2 and CaTiO3 at T D 1046 K. This work was supported by a contract from Lawrence Livermore National Laboratory and by Department of Energy grant number DE-FG07-97ER45673.",

year = "1999",

month = feb,

doi = "10.1006/jcht.1998.0445",

language = "English (US)",

volume = "31",

pages = "229--243",

journal = "Journal of Chemical Thermodynamics",

issn = "0021-9614",

publisher = "Academic Press Inc.",

number = "2",

}

TY - JOUR

T1 - Thermodynamics of formation for zirconolite (CaZrTi2O7) from T = 298.15 K to T = 1500 K

AU - Putnam, Robert L.

AU - Navrotsky, Alexandra

AU - Woodfield, Brian F.

AU - Boerio-Goates, Juliana

AU - Shapiro, Jennifer L.

N1 - Funding Information: We wish to acknowledge B. Ebbinghaus for the Rietveld refinement of the lattice parameters for zirconolite, R. VanKonynenburg at Lawrence Livermore National Laboratory for synthesis of the zirconolite sample, and D. Dooley for her work in our laboratory on TiO2 and CaTiO3 at T D 1046 K. This work was supported by a contract from Lawrence Livermore National Laboratory and by Department of Energy grant number DE-FG07-97ER45673.

PY - 1999/2

Y1 - 1999/2

N2 - Zirconolite (CaZrTi2O7) has been proposed as a ceramic host for the long-term disposal of excess weapons-grade plutonium. Using high-temperature oxide-melt solution calorimetry, the standard molar enthalpy of formation at T = 298.15 K for zirconolite, ΔfHom = -(3713.7 ± 4.5) kJ·mol-1, has been obtained. In combination with the third-law entropy Δ298.15 K0 Som obtained by using adiabatic calorimetry on the same sample, the standard molar Gibbs free energy of formation at T = 298.15 K, ΔfGom = -(3514.5 ± 4.5) kJ·mol-1, has also been obtained. The formation enthalpies, free energies, and third-law entropies ΔT0 Sm are reported from T = 298.15 K to T = 1500 K. Also reported for ZrTiO4, a compound of interest with respect to the (CaO, TiO2, ZrO2) phase diagram containing zirconolite, are the first estimates of the standard molar enthalpy and Gibbs free energy of formation, ΔfHom(ZrTiO4) = -(2048.7 ± 5.0) kJ·mol-1, and ΔfGom(ZrTiO4) = -(1935.7 ± 5.0) kJ·mol-1.

AB - Zirconolite (CaZrTi2O7) has been proposed as a ceramic host for the long-term disposal of excess weapons-grade plutonium. Using high-temperature oxide-melt solution calorimetry, the standard molar enthalpy of formation at T = 298.15 K for zirconolite, ΔfHom = -(3713.7 ± 4.5) kJ·mol-1, has been obtained. In combination with the third-law entropy Δ298.15 K0 Som obtained by using adiabatic calorimetry on the same sample, the standard molar Gibbs free energy of formation at T = 298.15 K, ΔfGom = -(3514.5 ± 4.5) kJ·mol-1, has also been obtained. The formation enthalpies, free energies, and third-law entropies ΔT0 Sm are reported from T = 298.15 K to T = 1500 K. Also reported for ZrTiO4, a compound of interest with respect to the (CaO, TiO2, ZrO2) phase diagram containing zirconolite, are the first estimates of the standard molar enthalpy and Gibbs free energy of formation, ΔfHom(ZrTiO4) = -(2048.7 ± 5.0) kJ·mol-1, and ΔfGom(ZrTiO4) = -(1935.7 ± 5.0) kJ·mol-1.

KW - Calorimetry

KW - Enthalpy of formation

KW - Nuclear waste

KW - Plutonium disposition

KW - Thermodynamic properties

KW - Zirconolite (CaZrTiO)

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