The viscosities of CaO-SiO2-10wt%MgO-20wt%Al2O 3-Na2O slags (CaO/SiO2=0.8-1.2, wt%Na 2O=0-10) were measured to estimate the effect of Na2O on the viscous behavior at elevated temperatures. The slag viscosity at 1773K decreased with increasing Na2Ocontents, which is observed in a basic oxide component. However, the FT-IR spectroscopic analysis of the slag structure seemed to verify that [AlO4]-tetrahedra depolymerized more readily than [SiO4]-tetrahedra due to ionic charge compensation which has a tendency to be more effective on [AlO4]-tetrahedra. Hence, for the present slag system, the viscosity decreased with additions of Na2O by providing network breaking O2- ions, and the charge balance by Na+ ions independently contributed to the depolymerization of the network structure of the molten slag. In addition, Na2O also lowered the critical temperature (TCR) resulting in a larger temperature difference between the operating temperature (TOP) and T CR, which can enhance operational stability.
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Physical and Theoretical Chemistry
- Metals and Alloys
- Materials Chemistry