APPLICATION OF SIMPLEX LATTICE METHOD FOR COMPOSITION-VISCOSITY PLOTTING OF СаО – SiO2 – В2О3 SLAGS WITH 15 % Al2O3 AND 8 % MgO

The results of composition-viscosity plotting for slag of the CaO – SiO2 – B2O3 system containing 15 % of Al2O3 and 8 % of MgO using simplex lattice method are given in this paper. It allows obtaining mathematical models describing property dependence on composition as a continuous function. The study was subjected to a fixed area in a form of local simplex represented by two CaO – SiO2 – B2O3 concentration triangles. The experiment was planned in pseudo-component coordinates. To describe dependence of slag viscosity on its composition, a mathematical model of polynomial of the third degree was chosen. In experiment planning matrix, slag compositions are given in pseudo-components and original components coordinates. Slags corresponding to studied local simplex vertex composition were melted in graphite crucibles from pre-heated oxides of ChDA brand. Composition of slag, corresponding to the points of local simplex plan, was obtained by counter-mixing of simplex vertex slag. In experiments, molybdenum crucibles were used to measure slags viscosity. Measurements were carried out using an electric vibrational viscometer in an argon flow with continuous cooling of melt from homogeneous-liquid to solid state. The results of generalization of mathematical modeling and graphical representation presented in form of compositionpropertydiagrams made it possible to quantify effect of slag basicity and B2O3 content on viscosity of resulting oxide system. The slag of CaO – SiO2 – B2O3 oxide system, containing 15 % of Al2O3 and 8 % of MgO, is characterized by sufficiently low viscosity in temperature range of 1450 – 1500 °C. Viscosity of such slags increases significantly with temperatures decrease to 1400 °C. It has been established that slags with basicity of 2 to 5, containing 1 to 4 % of B2O3 , are characterized by high liquid mobility at constant concentrations of Al2O3 (15 %) and MgO (8 %), their viscosity in temperature range of 1450 – 1500 °C does not exceed 4 – 7 poise. Such slags have, as a rule, high refining properties and can be recommended for the formation on a ladle furnace installation.