The transported entropy of Na+ in solid state cryolite

  • V. S. Sharivker
  • S. Kjelstrup Ratkje
Transport Phenomena


The transported entropy of Na+ in mixtures of NaF (s) and Na3AlF6 (s) is determined from thermocell experiments. The experiments were favorably described by the electric work method. The variation observed in the thermocell electromotive force (emf) with composition can be explained from the probable path of charge transfer in the electrolyte. The transported entropies are S*cry Na+ = 140 ± 7 J K−1 mol−1 for cryolite and S*NaFNa+ = 81 ± 8 J K−1 mol−1 for sodium fluoride between 380 °C and 500 °C. The value obtained for sodium in the solid cryolite makes us predict that the transported entropy for Na+ in themolten electrolyte mixture for aluminum production is substantial and that the reversible heat effects in the aluminum electrolysis cell are the same.


Entropy Material Transaction Seebeck Coefficient Thermoelectric Power Cryolite 
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Copyright information

© The Minerals, Metals & Materials Society - ASM International - The Materials Information Society 1996

Authors and Affiliations

  • V. S. Sharivker
    • 1
  • S. Kjelstrup Ratkje
    • 1
  1. 1.Department of Physical Chemistry, Norwegian Institute of TechnologyUniversity of TrondheimTrondheimNorway

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