Experimental phase diagram study of the binary KCl-Na2CO3 system

The phase diagram of the KCl-Na2CO3 system was experimentally investigated for the complete range of compositions using differential scanning calorimetry (DSC). The results are in excellent agreement with the phase diagram that is computed by the two-sublattice models. Both DSC experimental curves and the Tammann diagram were used to determine the eutectic point and the results were compared. The latter provides more reliable and accurate information with the eutectic composition found to be 50.41 +/- 0.78 wt% Na2CO3 (41.67 +/- 0.68 mol % KCl-Na2CO3). Physical properties at the eutectic point including solidification/melting temperature and latent heat of fusion/solidification were also studied. The results show a melting point of 581.76 +/- 0.57 degrees C and latent heat of fusion of 260.40 +/- 8.69 J/g. The occurrence of subcooling with a temperature difference of 5.58 +/- 0.67 degrees C was also identified. The existence of a solid solution was confirmed in the current investigation using the Tammann diagram and Scanning Electron Microscopy/Energy Dispersive X-ray Spectroscopy (SEM-EDS).

Automated summary

The phase diagram of the KCl-Na2CO3 system was experimentally investigated using DSC, with the eutectic point and composition determined through the Tammann diagram. The physical properties at the eutectic point were accurately studied, confirming the existence of a solid solution.