Precipitation of rare earth phosphates from NaCl-2CsCl eutectic based melts

Abstract

The reaction between 15 rare earth chlorides (yttrium, lanthanum and all the lanthanides except for promethium) and sodium orthophosphate was studied in NaCl-2CsCl eutectic based melts between 550 and 750 °C under an inert atmosphere. Rare earth phosphates were precipitated from the melt and their composition determined from chemical analysis, vibrational spectroscopy and X-ray powder diffraction measurements. The effects of temperature and the initial phosphate-to-rare earth mole ratio in the melt on the phase composition of the precipitated phosphates was investigated Over 99.9% precipitation could be achieved and the mole ratio required varied between 2 and 6. The minimum excess of phosphate precipitant required for complete precipitation from the melt was determined. Copyright © 2012 by The Electrochemical Society.