Physical Properties of CaO–SiO2–B2O3 Slags Containing 15% Al2O3 and 8% MgO

Abstract

The simplex lattice method has been applied to studying the chemical composition influence of CaO–SiO₂–B₂O₃ oxide system containing 15% Al₂O₃ and 8% MgO on viscosity and solidification point (hereinafter wt % are used). The addition of boron oxide to slags of the considered oxide system expands the range of slag composition with low solidification point and viscosity. The slags with basicity of 2.0–3.0 containing 1– 3% B₂O₃ are characterized by low (1400–1450°C) solidification point and high viscosity. Viscosity of such slags upon their heating to 1550 and 1600°C does not exceed 0.20 and 0.15 Pa s, respectively. An increase in B₂O₃ content to 4–6% in slags with basicity of 2.0–3.0 is accompanied by a decrease in solidification point to 1350–1425°C with retention of low (not higher than 0.15 Pa s) viscosity at heating temperature of 1550 and 1600°C. Generated slag displacement containing 1–6% B₂O₃ to the basicity regions increasing to 3.0–5.0 retains a sufficiently high fluidity. Herewith, it can be observed that the considered oxide system is displaced to a low solidification point region with an increase in boron oxide concentration. A slag solidification point with basicity of 3.0–4.0 containing 6% B₂O₃ reaches 1400°C and actually does not exceed 1475°C for the slags with basicity of 4.0–5.0 containing 1–2% B₂O₃. At 1600°C, the slag viscosity varies from 0.15 Pa s at basicity of 3.0 and B₂O₃ content of 5– 6% to 0.25 Pa s at basicity of 4.0–5.0 and B₂O₃ content of 1–3%. A temperature decrease of the considered oxide system by 50°C is accompanied by an insignificant (not more than 0.05 Pa s) increase in viscosity.