Surface tension of the molten NaCl-KCl-PbCl2 system

The surface tensions of the molten NaCl-KCl, KCl-PbCl2 and NaCl-PbCl2 binary systems have been calculated based on Butler's equation, in which a phase segregation coefficient omega and a special value of beta parameter are introduced, and by using STCBE (Surface Tension Calculation based on Butler's Equation) computer program in combination with excess. Gibbs energy parameters optimized by CALPHAD (computer CALculation of PHAse Diagram) technique. The agreement between the calculated results and the available experimental data is very good. Furthermore, the surface tensions of the NaCl-KCl-PbCl, ternary system with constant PbCl2 (60 mol%) and constant KCl / NaCl (50:50) at different temperatures have been calculated. Within the experimental accuracy the calculated results are in good agreement with the experimental data and increasing the temperature decreases the surface tension. The surface tensions of the equi-molar of NaCl and KCl in the NaCl-KCl-PbCl2 ternary system at 823 and 873K have a minimum at a PbCl2 content of approximately 50mol%. This behavior is mostly due to the formation of surface active PbCl2+nn- complexes verified from the study of Raman spectra.