Technological estimation of skull effect on steel melting parameters in basic oxygen furnace

Increasing the lining life of basic oxygen furnaces (BOF) reduces the expenses for refractories. Application of skull lining layer on the working surface is a good way to improve the efficiency of refractories. Features of the application of slag skull by the method of blowing a slag from previous melt with gas jet are discussed in the paper. It is shown that the presence of skull on the surface of the oxygen converter working lining affects not only the campaign duration of the unit, but also the technological parameters of steel melting, connected with its slag and thermal conditions. To quantify this effect, calculations of melting indices were performed for the conditions of BOF shop of PJSC MMK using a mathematical model based on the balance-statistical equations of physicochemical and thermal processes of oxygen-converter steel smelting. Taking into account the fact, that the skull is involved in the process as an additional material, that introduces slag-forming components and physical heat, the corresponding article of the heat balance was added to the program for melting parameters calculating. Assessment of the change of the amount of slag in the BOF in the course of steelmaking, knowing the possible arrival of the components from skull, was carried out. The calculations results of the change of the of melt metal components mass from the percentage of skull in the BOF are presented. The dependence of the change of the consumption of charge components on the amount of skull in the BOF is presented. It is shown that with an increase of the skull amount for smelting of the same steel mass some increase of metal charge will be required. This fact can be explained by increased iron loss with oxides, metallic beads and additional oxygen consumption for oxidative refining of the melt.