Vacuum distillation of a mixture of LiCl-KCl eutectic salts and RE oxidative precipitates and a dechlorination and oxidation of RE oxychlorides

J Hazard Mater. 2008 Dec 30;160(2-3):634-7. doi: 10.1016/j.jhazmat.2008.03.079. Epub 2008 Mar 22.

Abstract

In this study, a vacuum distillation of a mixture of LiCl-KCl eutectic salt and rare-earth oxidative precipitates was performed to separate a pure LiCl-KCl eutectic salt from the mixture. Also, a dechlorination and oxidation of the rare-earth oxychlorides was carried out to stabilize a final waste form. The mixture was distilled under a range of 710-759.5Torr of a reduced pressure at a fixed heating rate of 4 degrees C/min and the LiCl-KCl eutectic salt was completely separated from the mixture. The required time for the salt distillation and the starting temperature for the salt vaporization were lowered with a reduction in the pressure. Dechlorination and oxidation of the rare-earth oxychlorides was completed at a temperature below 1300 degrees C and this was dependent on the partial pressure of O2. The rare-earth oxychlorides (NdOCl/PrOCl) were transformed to oxides (Nd2O3/PrO2) during the dechlorination and oxidation process. These results will be utilized to design a concept for a process for recycling the waste salt from an electrorefining process.

MeSH terms

  • Hypochlorous Acid / chemistry
  • Lithium Chloride / analysis*
  • Metals, Rare Earth / chemistry*
  • Oxidation-Reduction
  • Potassium Chloride / analysis*
  • Temperature
  • X-Ray Diffraction

Substances

  • Metals, Rare Earth
  • Potassium Chloride
  • Hypochlorous Acid
  • Lithium Chloride