Identification of ions present in LiF-DyF3 melts and the mechanism of Dy2O3 dissolution therein

• Published in: Journal of rare earths 2019-02, Vol.37 (2), p.211-217
• Main Authors: Liao, Chunfa, Chen, Shumei, Wang, Xu, Cai, Boqing, Lin, Jueyuan, Jiao, Yunfen, Zeng, Yanliang
• Format: Article
• Language: English
• Subjects: Dissolution mechanism; Flood model; LiF-DyF3-Dy2O3 melt; Melting enthalpy; Primary crystallization temperature; Temkin model
• ISSN: 1002-0721; 2509-4963
• DOI: 10.1016/j.jre.2018.05.014

Herein, the present paper were attempted to identify ions in LiF-DyF3 melts according to the law of decreasing primary crystallization temperature and model analysis. Specifically, the primary crystallization temperatures of LiF-DyF3 and LiF-DyF3-Dy2O3 melts with various DyF3 and Dy2O3 contents were determined by differential scanning calorimetry (DSC), and reactions occurring in the above melts were investigated using ideal dilute solution (Temkin and Flood) models. Moreover, crystal phases produced by rapid solidification of LiF-DyF3, LiF-Dy2O3, DyF3-Dy2O3, and LiF-DyF3-Dy2O3 melts were identified by X-ray diffraction (XRD) analysis. The primary crystallization temperature of LiF-DyF3 melts exhibits an approximately linear decrease with increasing molar fraction of DyF3, and the general formula of complex ions in these melts is expressed as DyFx(3−x), e.g., DyF4−. Finally, we investigated the dissolution of Dy2O3 in LiF-DyF3 melts, showing that it was chemical in nature and afforded Dy1+xO3xF3–3x and DyOF. Relationship between the primary crystallization temperature of LiF-DyF3 melts and the mole fraction of DyF3 therein. The primary crystallization temperature of LiF-DyF3 dilute melts exhibits an approximately linear decrease with increasing molar fraction of DyF3. [Display omitted]