Transition of Blast Furnace Slag from Silicates-Based to Aluminates-Based: Viscosity

Abstract

The effect of Al 2 O 3 and the Al 2 O 3 /SiO 2 (A/S) ratio on the viscosity of the CaOSiO 2 -Al 2 O 3 -MgO-TiO 2 slag system was studied in the present work. At a fixed CaO/SiO 2 (C/ S) ratio of 1.20, 9 mass pct MgO, and 1 mass pct TiO 2 , the viscosity increases with an increase in Al 2 O 3 content at a range of 16 to 24 mass pct due to the polymerization of the aluminosilicate structures, while it decreases when the Al 2 O 3 is higher than 24 mass pct, which means that Al 2 O 3 acts as a network modifier at higher content. Increasing A/S from 0.47 to 0.92 causes a slight decrease in viscosity of the slags and has an opposite effect when A/S is more than 0.92. The free running temperature increases with the Al 2 O 3 content and appears to show a peak at an A/S ratio of 0.92. The change of the apparent activation energy is in accordance with the change of viscosity. When Al 2 O 3 content is more than 24 mass pct with low SiO 2 , CaO content ranges from 35 to 45 mass pct, and the slag transform from silicates-based to aluminates-based can still get a good operation region. Four different viscosity models were employed to predict the viscosity and RIBOUD's model was found to be the best in predicting the viscosity by comparing the estimated viscosity with the measured viscosity.

Viscosity and Structure of CaO–SiO2–“FeO”–Al2O3–MgO System during Iron‐Extracting Process from Nickel Slag by Aluminum Dross. Part 2: Influence of Al2O3/SiO2 Ratio

“…The temperature dependence of viscosity can be described as the Arrhenius formula, Equation where η is the slag viscosity (Pa · s), A is the pre‐exponential factor, E v is the apparent activation energy (kJ mol −1 ), R is the gas constant (8.314 J mol −1 K −1 ), and T is the slag temperature (K).…”

“…Whereas, the viscosity increased after the ratio higher than 0.56, which was attributed to the presence of spinel crystals. Yan et al studied the slag viscosity of the CaO–SiO 2 –MgO–Al 2 O 3 –(1 wt%)TiO 2 system. The increment of Al 2 O 3 /SiO 2 ratio from 0.47 to 0.92 caused a slight decrease in the viscosity of the slags, which was speculated as the weaker bonding strength of Al–O than that of Si–O.…”

Effect of TiO₂ on the Liquid Zone and Apparent Viscosity of SiO₂-CaO-8wt%MgO-14wt%Al₂O₃ System

“…The experimental arrangement including the dimensions of the crucibles and spindle have been provided elsewhere. 11,12) A rotating viscometer (Brookfield, model LVDV-II + Pro, Middleboro, MA) set on the furnace was connected with a computer to record the value of the torque from the rotation of the spindle. The heater of the furnace is made of MoSi 2 .…”

Smelting separation behaviors and mechanisms of high-alumina rich-manganese ore obtained from metallic reduction and magnetic separation

“…The influence of alumina on the viscosity decrease can be explained on the basis of a decrease in the degree of polymerization by the increase in the relative fraction of the [AlO 6 ]-octahedral units. The slag transforms from silicates-based to aluminates-based with an increase of Al content and Al/Si ratio [20]. Therefore, the high-alumina rich-manganese ore containing high Al 2 O 3 content and Al/Si ratio were applied to smelt HCFeMn alloy to research the substitution of SiO 2 with Al 2 O 3 , and provide an opportunity to explain smelting and separation mechanisms.…”