The influence of parameters of slag conditions on blast furnace smelting performance and cast iron quality

The analysis of production data on the operation of the blast furnace No. 2 for the period from 2021 to 2023 is carried out. The results of the influence of parameters of slag conditions on the technical and economic indicators (TEI) of blast furnace operation and the quality of cast iron are presented. It was found that when analyzing the performance indicators of the blast furnace operation and the results of desulfurization under conditions of instability of the composition of charge and slag, it is necessary to use the indicator of the total or complete slag basicity, which gives more objective results, unlike simple basicity. It is shown that the slag procedure should be characterized by a minimal basicity that ensures achievement of a specified cast iron quality, in order to achieve the best TEI of the blast furnace. To improve the conditions and results of metal desulfurization, it is advisable to adjust the slag composition towards increasing the MgO content to 9–10 % while reducing the level of simple slag basicity to 0.95 units and maintaining the value of the total basicity at the level of 1.16–1.18 units. In addition, it is expedient to ensure that the Al2O3/SiO2 ratio is maintained at the level of 0.2–0.25 units. When maintaining the proposed slag conditions, in addition to improving the conditions and results of desulfurization, a decrease in slag amount can be expected. This, together with the improvement of the slag physical properties (viscosity and fluidity), will reduce coke consumption and provide conditions for increasing the blast furnace productivity. The work was carried out with the financial support of the Ministry of Higher Education of Russian Federation (project No. FZRU-2023-0008) and the Russian Science Foundation, grant No. 23-79-30015 (Agreement dated 13.04.2023, http://rscf.ru/project/23-79-30015/).