Abstract
The viscosities of CaO-SiO2-CaCl2 (CaO/SiO2 = 1.12) slags were measured to elucidate the effect of chlorine with CaCl2 content from 0 to 15 mass pct on the slags at high temperatures, and the Raman spectra of the glassy slags were detected to account for the role of chlorine in modifying the structures of the slags. The viscosity was found to increase with decreasing temperature and to decrease with increasing chlorine content at a given temperature. The critical temperature (TCR) decreased from about 1675 K to 1621 K (1402 °C to 1348 °C) with increasing CaCl2 content from 5 to 15 mass pct, and the activation energy decreased from 226 to 152 kJ/mol with CaCl2 content increasing from 0 to 15 mass pct. Meanwhile, the Raman spectra gradually shifted to lower wavenumber, the fractions of Q0 and Q2 units increased and the Q1 and Q3 units decreased continuously, and the Q3/Q2 ratio generally decreased with increasing the chlorine content in the investigated slags; all of these results above demonstrated the role of network modifier of the chlorine in decreasing the degree of polymerization in the silicon-oxygen tetrahedra.