Contributors: Conditions Extrêmes et Matériaux : Haute Température et Irradiation (CEMHTI); Université d'Orléans (UO)-Institut de Chimie - CNRS Chimie (INC-CNRS)-Centre National de la Recherche Scientifique (CNRS); This work was supported by the National Natural Science Foundation of China (21773152, 22003039), the National 111 Project (D17002, the Program of Introducing Talents of Discipline to Universities), the Key Basic Research Projects of the Basic Strengthening Plan of the Commission of Science and Technology (2021-JCJQ-ZD-051-00-02), the Shanghai Committee of Science and Technology Fund, China (12520709200), the Open Project Program of the State Key Laboratory of Advanced Special Steel, Shanghai University, China (SKLASS2020-06), the Special Fund Project of Shanghai Municipality for Science and Technology Development (YDZX20173100001316), and the China Scholarship Council (CSC No. 202106890001).
نبذة مختصرة : International audience ; The microstructure of the molten alumina-cryolite system is an important aspect in the dissolution behavior of alumina (α-Al 2 O 3 ) in cryolite (Na 3 AlF 6 ) molten salt and impacts the physical properties of the molten system. In this work, the symmetric stretching vibrational wavenumbers of aluminum nonbridging fluorine (AlF x 3-x ) and aluminum-oxygen-fluorine (Al 2 OF y 4-y , and Al 2 O 2 F z 2-z ) bonds in the high wavenumber range, as well as their corresponding Raman scattering cross sections (RSCS), were first analyzed and determined by quantum chemistry (QC) ab initio calculations. The species in binary Al 2 O 3 -Na 3 AlF 6 melts with varying Al 2 O 3 contents were then qualitatively and quantitatively analyzed using in situ high-temperature Raman spectroscopy in conjunction with first principles calculation. The species of AlF 4 -, AlF 5 2-and AlF 6 3-were found to be present and predominant in the melts with Al 2 O 3 contents ranging from 0 to 6.0 wt%. The content of Al 2 OF 6 2-species tended to increase with Al 2 O 3 content from 0 to 3.0 wt%, while Al 2 O 2 F 4 2-species only existed in the melts with an Al 2 O 3 concentration of more than 3.0 wt%. Finally, the abundance of various species in the molten Al 2 O 3 -Na 3 AlF 6 system was further correlated to the melt viscosity. The contribution to viscosity was primarily determined by the distribution of AlF x 3-x (x=4, 5, and 6) and Al 2 OF 6 2-species, and the contribution ability of corresponding species to viscosity was Al 2 OF 6 2-, AlF 6 3-, AlF 5 2-and AlF 4 -from largest to smallest.
Processing Request
No Comments.