Thermodynamic studies of zippeite, a uranyl sulfate common in mine wastes

Melika Sharifironizi, Jennifer E.S. Szymanowski, Ginger E. Sigmon, Alexandra Navrotsky, Jeremy B. Fein, Peter C. Burns

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Zippeite is a potassium uranyl sulfate mineral that forms on uranium mine wastes and that may be important in nuclear waste disposal. Little is known about its thermodynamic properties. In this study, we synthesized zippeite, K3(H2O)3.3[(UO2)4(SO4)2O3(OH)], and measured its thermodynamic properties. The standard enthalpy of formation of zippeite from the elements, − 8655.97 ± 12.55 kJ/mol, was calculated from the measured enthalpy of dissolution in a high-temperature oxide melt solution calorimeter. Solubility measurements were conducted from both undersaturation and supersaturation in order to constrain the equilibrium state. Using the solubility product (Ksp) obtained from the solubility data, the standard Gibbs free energy of formation of zippeite at 298 K was calculated to be − 7783.44 ± 6.87 kJ/mol. This value, coupled with the standard enthalpy of formation value determined from the calorimetric data, was then used to calculate the standard entropy of formation, − 2926.49 ± 45.64 J/mol. Our studies yield the first complete set of thermodynamic properties of zippeite, and the results allow us to predict the conditions under which its formation is favorable relative to other uranyl minerals under a wide range of conditions of geologic and engineering interest.

Original languageEnglish (US)
Pages (from-to)54-58
Number of pages5
JournalChemical Geology
Volume447
DOIs
StatePublished - Dec 30 2016

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mine waste
Sulfates
thermodynamic property
thermodynamics
enthalpy
Thermodynamics
sulfate
Enthalpy
solubility
Thermodynamic properties
Solubility
Sulfate minerals
Uranium mines
Radioactive Waste
Gibbs free energy
Supersaturation
supersaturation
mineral
Calorimeters
Waste disposal

All Science Journal Classification (ASJC) codes

  • Geology
  • Geochemistry and Petrology

Cite this

Sharifironizi, M., Szymanowski, J. E. S., Sigmon, G. E., Navrotsky, A., Fein, J. B., & Burns, P. C. (2016). Thermodynamic studies of zippeite, a uranyl sulfate common in mine wastes. Chemical Geology, 447, 54-58. https://doi.org/10.1016/j.chemgeo.2016.10.022
Sharifironizi, Melika ; Szymanowski, Jennifer E.S. ; Sigmon, Ginger E. ; Navrotsky, Alexandra ; Fein, Jeremy B. ; Burns, Peter C. / Thermodynamic studies of zippeite, a uranyl sulfate common in mine wastes. In: Chemical Geology. 2016 ; Vol. 447. pp. 54-58.
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Sharifironizi, M, Szymanowski, JES, Sigmon, GE, Navrotsky, A, Fein, JB & Burns, PC 2016, 'Thermodynamic studies of zippeite, a uranyl sulfate common in mine wastes', Chemical Geology, vol. 447, pp. 54-58. https://doi.org/10.1016/j.chemgeo.2016.10.022

Thermodynamic studies of zippeite, a uranyl sulfate common in mine wastes. / Sharifironizi, Melika; Szymanowski, Jennifer E.S.; Sigmon, Ginger E.; Navrotsky, Alexandra; Fein, Jeremy B.; Burns, Peter C.

In: Chemical Geology, Vol. 447, 30.12.2016, p. 54-58.

Research output: Contribution to journalArticle

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T1 - Thermodynamic studies of zippeite, a uranyl sulfate common in mine wastes

AU - Sharifironizi, Melika

AU - Szymanowski, Jennifer E.S.

AU - Sigmon, Ginger E.

AU - Navrotsky, Alexandra

AU - Fein, Jeremy B.

AU - Burns, Peter C.

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