Abstract The aim of this work was to examine the use of mixtures of high basicity ore sinters and acidic pellets in blast furnace charge. The proportion of high basicity sinters and acidic pellets depends on both the nature and basicity of the latter and is used to obtain desired slag properties as well as sufficient reducibility and mechanical strength of the furnace charge. Such an optimization of the composition of the charge brings a considerable cost reduction related to coke saving, elimination of fluxes and decrease in air pollution. The interpretation of reactions between high basicity sinters and acidic pellets in the 1130–1250°C temperature range is possible on the basis of former separate results concerning sinters and pellets or constituent phases obtained synthetically: calcium- and magnesium-doped magnetite and wustite, olivines and calcium ferrites. Particular attention was paid to the conditions of formation of the phases.