Study of the viscosity of slags of ??? - SiO2 - ?2?3 - 25 % Al2O3 - 8 % MgO System

Abstract

The effect of the B2O3 content and the slag basicity on the viscosity of the CaO–SiO2–B2O3 system containing 25 % Al2O3 and 8 % MgO2 was studied using a simplex-lattice method of experiment planning that allows obtaining mathematical models describing the dependence of the property on the composition as a continuous function. Synthetic slags, corresponding to the composition of simplex under study, were smelted in graphite crucibles from pre-calcined oxides. The composition of slags, corresponding to the remaining points of the local simplex plan, was obtained by counter-packing the slags of simplexes. The viscosity of the slag was measured in molybdenum crucibles by means of an electrovib-rational viscometer in an argon flow with continuous cooling of the melt from a homogeneous-liquid to a solid state. Mathematical models were constructed that describe the relationship between the temperature of a given viscosity and the composition of the oxide system using experimental data. Then, a set of viscosity isolines was obtained by combining the obtained composition-temperature diagrams of the given viscosity with the isothermal section of the composition-viscosity diagram. The generalization of mathematical modeling results and graphical imaging on the isothermal profile of the composition-viscosity diagram made it possible to obtain new data on the viscosity of the CaO–SiO2–B2O3 oxide system containing 25 % Al2O3 and 8 % MgO in the basic 2–5 range and 1–10 % B2O3 content. The slags of the oxide system under study in the temperature range of 1400–1500 °C are characterized by low viscosity. At a temperature of 1400 °C, the viscosity of slag with basicity 2.0–2.5, containing 7–10 % B2O3 does not exceed 3–4 Ps. The displacement of the slag into the basicity of 3–5 is accompanied by a decrease in B2O3 content to 2–6 % by increasing the slag viscosity to 12 Ps. An increase in temperature to 1450 °C leads to a significant decrease in the viscosity of slags with basicity of 2–3, even for slag with B2O3 content of 4 %, it does not exceed 4 Ps and increases to 6 Ps in the basicity of 3–5 and B2O3 content of 1–3 %. The slag viscosity in the basicity of 3–5 at B2O3 content of 1–4 % does not exceed 4 Ps at a temperature of 1500 °C. © 2017, National University of Science and Technology MISIS. All rights reserved.