INFLUENCE OF B2O3 AND CaO–SiO2 –B2O3 –Al2O3 SLAG SYSTEM BASICITY ON CONCENTRATION OF MAGNESIUM OXIDE SATURATION

Study of the effect of boron oxide and basicity of CaO – SiO₂–B₂O₃  – Al₂ O₃ slag system on MgO saturation concentration was carried out using the simplex lattice method of experimental design, which allows one to construct mathematical models describing dependence of studied property on composition as a continuous function. Synthetic slags, corresponding in composition to vertices of studied simplex, were smelted in graphite crucibles from previously calcined oxides of analytical grade. Slag compositions corresponding to the remaining points of local simplex plan were obtained by counterblending slags of simplex tops. Using experimental data, mathematical models adequately describing effect of slag composition on saturation concentration of MgO were constructed. Graphic image of mathematical modeling results is represented by the composition diagram – saturation concentration of MgO. Analysis of experimental data presented in diagram made it possible to obtain new information on the effect of boron oxide and basicity of CaO – SiO₂  – B₂O₃ slags system containing Al₂O₃ on MgO saturation concentration. It was established that in slags formed in basicity range of 2  –  3 and B₂O₃ content of 1  –  3  %, saturation concentration of MgO varies from 3 to 9  %. Increase in B₂O₃ content in slag to 4  % leads to an increase in MgO saturation concentration in slag of 11  –  13  %. Displacement of slags to area of increased basicity up to 3  –  4 is characterized by a decrease in MgO saturation concentration to 2  –  5  %, with 1  –  3  % of В₂О₃ content and an increase to 7  –  9  % at 3  –  4  % В₂О₃ in slag. Formation of slags in basicity range of 4  –  5 and B₂O₃ content of 1  –  3  % does not lead to a significant decrease in concentration of slag saturation with magnesium oxide. Saturation concentration of MgO in slag in this area of basicity varies from 2 to 4  % and practically does not reach 7  % with an increase in В₂О₃ content to 4  %. At the same time, there is an increase in cost of steel due to an increase in consumption of lime and material containing boron oxide.

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