Effects of CaO/Al 2 O 3,Nb 2 O 5 and SiO 2 on the viscosity and structure of molten CaO-Al 2 O 3 -5%MgO-SiO 2 -Nb 2 O 5 system

Abstract

The viscosity of CaO-Al₂O₃-5%MgO-SiO₂-Nb₂O₅ molten slags was measured experimentally. The effects of CaO/Al₂O₃ ratio, Nb₂O₅ content, and SiO₂ content on the viscous behavior of niobium-containing slags were investigated, and the effect of each factor on the microstructure of molten slag was explored by molecular dynamics (MD) simulation. The experimental results show that the viscosity of the molten slag decreases with the increase of CaO/Al₂O₃ ratio and the SiO₂ content, increases with the increase of Nb₂O₅ content. The results of the MD showed that an increase in CaO/Al₂O₃ ratio and SiO₂ content reduced slag polymerization. Meanwhile, an increase in Nb₂O₅ content increased slag polymerization. Changes in slag polymerization result in corresponding changes in slag viscosity. The present experimental data were utilized to modify several viscosity prediction models. Among these models, the modified NPL model was found to be more effective in predicting the viscosity of molten niobium-containing slag at high temperatures.