Study of phase equilibria in LiCl-KCl-PrCl3 pseudo-ternary system

The pseudo-ternary phase diagram of LiCl-KCl-PrCl3 has been investigated to understand the interaction of PrCl3 with LiCl-KCl molten salt medium by differential thermal analysis (DTA) technique and characterization of the coexisting phases in the solid state using X-ray diffraction (XRD). The results of these experiments showed that the LiCl-KCl-PrCl3 system consists of two quasi-ternary sections, namely (1) LiCl-KCl-K2PrCl5 section which has a ternary eutectic temperature of 591 ± 4 K and approximate eutectic composition of 55.1 mol% LiCl-39.6 mol% KCl-5.3 mol% K2PrCl5 and (2) LiCl-K2PrCl5-PrCl3 section having a ternary eutectic temperature of 654 ± 7 K and approximate eutectic composition of 46.8 mol% LiCl-32.2 mol% K2PrCl5-21.0 mol% PrCl3. A pseudo-ternary peritectic reaction at 762 ± 1 K is observed at 22.3 mol% LiCl-39.6 mol% KCl-38.1 mol% K2PrCl5. Isothermal sections at selected temperatures and the polythermal liquidus projection with isothermal contours are drawn over the ternary phase field.