"Calculation results for predictive conditions of blast furnace operation are presented with the use of converter slag in the iron ore portion of the blast furnace burden without additional measures in order to estimate the influence of converter slag on process performance parameters. Fractional converter slag can be added to the blast furnace burden to increase magnesia concentration in the burden and used as the basic flux to increase the proportion of pellets in the burden of an individual furnace not changing the established sinter basicity for the entire blast-furnace plant. This increases gas perme- ability of the dry burden for a blast furnace with the limiting upper zone in case of its profile distortion. Loading of con- verter slag into the blast furnace causes an increased quantity of phosphorus in cast iron. Long-term use of converter slag in the burden of all blast furnaces will be accompanied by accumulation of phosphorus in metal and will lead to increasing problems regarding phosphorus removal at the converter production stage. By proportioning the burden components, the content of ferrum in the fluxed burden can be kept at the level which satisfies the technology requirements and pro- vides economical conditions of blast furnace operation. The issue of efficient use of converter slag in blast furnaces can be settled by the complex analysis of the problem: evaluation of economic feasibility of its use as a fluxing agent; feasibility study of this issue for the “blast-furnace production - converter production” complex; selection of the technological mode of blast furnaces operation in accordance with operation conditions; analysis of environmental problems during operation at the factory and in the region."