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Lynch TJ, Birkner NR, Christian MS, Wrubel JA, Schorne-Pinto J, Van Veelen A, Bargar JR, Besmann TM, Brinkman KS, Chiu WKS. In Situ Determination of Speciation and Local Structure of NaCl-SrCl 2 and LiF-ZrF 4 Molten Salts. J Phys Chem B 2022; 126:1539-1550. [PMID: 35138853 DOI: 10.1021/acs.jpcb.1c07552] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Understanding the local environment of the metal atoms in salt melts is important for modeling the properties of melts and predicting their behavior and thus helping enable the development of technologies such as molten salt reactors and solar-thermal power systems and new approaches to recycling rare-earth metals. Toward that end, we have developed an in situ approach for measuring the coordination of metals in molten salt coupling X-ray absorption spectroscopy (XAS) and Raman spectroscopy. Our approach was demonstrated for two salt mixtures (1.9 and 5 mol % SrCl2 in NaCl, 0.8 and 5 mol % ZrF4 in LiF) at up to 1100 °C. Near-edge (X-ray absorption near-edge structure, XANES) and extended X-ray absorption fine structure (EXAFS) spectra were measured. The EXAFS response was modeled using ab initio FEFF calculations. Strontium's first shell is observed to be coordinated with chlorine (Sr2+-Cl-) and zirconium's first shell is coordinated by fluorine (Zr4+-F-), both having coordination numbers that decrease with increasing temperature. Multiple zirconium complexes are believed to be present in the melt, which may interfere and distort the EXAFS spectra and result in an anomalously low zirconium first shell coordination number. The use of boron nitride (BN) powder as a salt diluent for XAFS measurements was found to not interfere with measurements and thus can be used for investigations of such systems.
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Affiliation(s)
- Timothy J Lynch
- Department of Mechanical Engineering, University of Connecticut, Storrs, Connecticut 06369-3139, United States
| | - Nancy R Birkner
- Department of Materials Science and Engineering, Clemson University, Clemson, South Carolina 29634-0901, United States
| | - Matthew S Christian
- Nuclear Engineering Program, University of South Carolina, Columbia, South Carolina 29208, United States
| | - Jacob A Wrubel
- Department of Mechanical Engineering, University of Connecticut, Storrs, Connecticut 06369-3139, United States
| | - Juliano Schorne-Pinto
- Nuclear Engineering Program, University of South Carolina, Columbia, South Carolina 29208, United States
| | - Arjen Van Veelen
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - John R Bargar
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Theodore M Besmann
- Nuclear Engineering Program, University of South Carolina, Columbia, South Carolina 29208, United States
| | - Kyle S Brinkman
- Department of Materials Science and Engineering, Clemson University, Clemson, South Carolina 29634-0901, United States
| | - Wilson K S Chiu
- Department of Mechanical Engineering, University of Connecticut, Storrs, Connecticut 06369-3139, United States
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Peckhaus A, Kiselev A, Wagner R, Duft D, Leisner T. Temperature-dependent formation of NaCl dihydrate in levitated NaCl and sea salt aerosol particles. J Chem Phys 2016; 145:244503. [DOI: 10.1063/1.4972589] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
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Talwar DN, Vandevyver M, Zigone M. Impurity induced Raman scattering spectra in zincblende-type crystals: application to mixed indium pnictides. ACTA ACUST UNITED AC 2000. [DOI: 10.1088/0022-3719/13/19/019] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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