Influence of Nb2O5 and basicity on the viscosity and structure of CaO-SiO2-Nb2O5-CeO2-CaF2 slag system

Abstract

In order to utilize niobium concentrate of Bayan Obo effectively, the effect of Nb2 O5 and basicity on the viscosity of CaO-SiO2 -Nb2 O5 -5.0 wt.% CeO2 -5.0 wt.% CaF2 slag system was studied from 1653 to 1813 K in reducing atmosphere by rotating cylinder method. For the same condition, the as-quenched samples were investigated through X-ray diffraction and Raman spectroscopy. The results show that the viscosity, break temperature and activation energy of viscous flow decrease with the increase of Nb2 O5 and basicity. Raman spectra show that the Nb4+ ions exist in the form of [NbO6 ] octahedron with different distortion and little [NbO4 ] tetrahedron in the slags. The Nb2 O5 addition and basicity lower the degree of polymerization, where the complex Si-O network is depolymerized into simple structural units.