STUDY OF THE VISCOSITY OF SLAGS OF СаО–SiO2 –В2 О3 – 25 % Al2 O3 – 8 % MgO SYSTEM

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 electrovibrational 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  °С, 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  °С.

boron containing slags, basicity, viscosity, experimental planning, composition-viscosity diagrams

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