Measurement of boiling temperatures and calculation of vapor pressure and thermodynamic values for lead and zinc chloride melts

摘要

Pressure of saturated vapor over melted mixtures PbCl_2-ZnCl_2 was measured experimentally within the range of T=850/1150 K over all range of compositions. The data are given as equation lgP==-(A+-DELTA A)/T+(B+-DELTA B), where constants are calculated by the least-squares method. Evaporation enthalpy and normal boiling temperatures have been calculated. Total pressure in the system was found taking the literature data on activities of the components into account. The calculated data obtained were compared with the experimental ones, their coincidence for certain compositions and temperatures was shown, and the causes of differences were explained. Activities of components at T=1000 K were calculated from the experimental data. The fusion diagram was analyzed taking the experimental data and the results of calculation on the basis of studying deviation from Raoult's law into account. The results have shown that the fusion diagram of PbCl_2-ZnCl_2 relates to eutectic type, and T=260 deg C and x_(PbCl_2)=0,2 are the most probable coordinates of the eutectic point.