Fundamental Study on a Salt Distillation from Mixtures of Rare Earth Precipitates and LiCl-KCl Eutectic Salt

A fundamental study on the distillation rate on LiCl-KCl eutectic salt under different vacuums from 66 to 6600 Pa (0.5 to 50 mm Hg) was performed by using both a nonisothermal and an isothermal thermogravimetric (TG) analysis. Based on the nonisothermal TG data, distillation rate equations as a function of the temperature could be derived. Calculated flux by these model flux equations was in agreement with the distillation rate obtained from isothermal TG analysis. A salt distillation operation with a moderated distillation rate of 10^-4 to 10^-5 molcm^-2s^-1 is possible at temperatures of <1300 K and vacuums of 660 to 6600 Pa. An [approximately]99% salt distillation efficiency was obtained after 1 h at a temperature above 1150 K under 6600 Pa. An increase in the vaporizing surface area is relatively effective for removing residual salt in the remaining particles, when compared to that for the vaporizing time. More than 99.95% of total distillation efficiency was obtained for a 1-h distillation operation by increasing the inner surface area from 4.52 to 12.56 cm² (about 3 times increase).