Electrical Conductivity of (LiCl–KCl)eut.–PbCl2 Molten Mixtures

Abstract

The electrical conductivity of molten (LiCl–KCl)_eut.–PbCl₂ has been measured from the liquidus temperature up to 901–994 K over the entire concentration range. Literature data on the (LiCl–KCl)–PbCl₂ density were recalculated to approximate them for our eutectic system. Using the calculated density values, the (LiCl–KCl)_eut.–PbCl₂ molar conductivity was calculated. The specific electrical conductivity of molten (LiCl–KCl)_eut.–PbCl₂ was found to decrease with PbCl₂ addition, while the molar conductivity increases. The molten PbCl₂ molar electrical conductivity is greater than the LiCl–KCl eutectic conductivity. For all molten mixtures, the ln Λ vs. 1/T dependence has a nonlinear form (Λ─molar conductivity, T─absolute temperature). At 773 K, the molar conductivity has positive deviations from additive values. The deviations shift in the negative direction and increase as the temperature grows (−5.3% at 973 K). This indicates a change in the predominant mechanism of electricity transfer as the temperature increases. Using breakpoints, the liquidus line of this system has been built. The activation energy of molar electrical conductivity decreases up to the PbCl₂ concentration of 30–40%, and then increases. The results are discussed by considering the available data on the structure of the melts.