Regular Article

Influence of basicity and MgO/Al₂O₃ ratio on the viscosity of blast furnace slags containing chloride

¹ School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China
² State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing 100083, China

^⁎ e-mail: zhang.jianliang@hotmail.com

Received: 23 September 2016
Received in final form: 31 October 2016
Accepted: 7 November 2016

Abstract

The viscosities of CaO–SiO₂–Al₂O₃–MgO–CaCl₂ slags under conditions of CaCl₂ = 0–10%, C/S = 0.90–1.30 and MgO/Al₂O₃ = 0.40–0.67 have been experimentally measured to elucidate the effect of chlorine, basicity and MgO/Al₂O₃ ratio on the viscous behavior of the blast furnace slag. Slag viscosity gradually increases with decreasing temperature, then sharply increases at the critical temperature, and it decreases with increasing chlorine content at temperatures over 1673 K. The critical temperature decreases from 1660 K to 1590 K with increasing chlorine content from 0% to 10% CaCl₂; this may be attributed to the variation of chemical potential of primary solid phase caused by adding chloride. Slag viscosity diminishes with increase in basicity, while MgO/Al₂O₃ ratio does not significantly affect the viscosity at temperatures higher than 1645 K. The tendency of the effect of basicity on the slag viscosity corresponds closely with that of corresponding CaO–SiO₂–Al₂O₃–MgO slags obtained from literature, while the trend of MgO/Al₂O₃ ratio influence is distinct from that. The activation energy of chlorine-containing slags under the range of 182.8 kJ/mol to 213.8 kJ/mol generally decreases with increasing chlorine content, basicity and MgO/Al₂O₃ ratio in slags. Due to the dual effect of the variation of polymerization and the primary phase by adding chloride, the MgO/Al₂O₃ ratio almost has no influence on the viscosity of the chlorine-containing slags at higher temperatures.