Study on the fluorination of dysprosium oxide by ammonium bifluoride for the preparation of dysprosium fluoride

Abstract

In this report, dysprosium fluoride (DyF₃) - a material for the preparation of dysprosium (Dy) metal was prepared by the fluorination of dysprosium oxide (Dy₂O₃) by ammonium bifluoride (NH₄HF₂) reagent. The effect of reaction time and temperature on the formation of dysprosium fluoride salt has been studied. The phase composition and crystal structure of the obtained products were analysed by X-ray diffraction (XRD). Thermal analysis techniques were applied to determine the temperature range of the fluorination. Scanning electron microscopy with energy dispersive spectroscopy (SEM/EDS) was used for external morphology observation and chemical elemental composition analysis.  The results showed that the high purity phase of DyF₃ was formed at the conditions: reaction time and temperature of >1 h and >350^oC, respectively. The product is available for the preparation of Dy metal by metallothermic reduction.