This paper analyzes the physical and chemical processes of sulfur removal during agglomeration of iron ore mineral raw materials to build a technologically efficient processing model. Thermodynamic aspects of the formation of sulfates are considered, taking into account the features of desulfurization of calcined ore materials in the presence of alkali-earth metal compounds in the charge of agglomerates, when sulfur dioxide is partially captured by them. It was found that the addition of limestone to concentrate and pure pyrite has no noticeable ef-fect on the removal of sulfur from the charge in the temperature range of 600-900 ° C during short-term firing due to the weak absorption of calcium carbonate by sulfur dioxide. Analysis of the agglomeration processes of sulfu-rous iron ore materials found that free lime absorbs sulfur well, since an intermediate stage is necessary for lime-stone absorption – dissociation of calcium carbonate. The factors contributing to decarbonization, which lead to a more complete removal of sulfide sulfur from oxidized iron ore materials, have been investigated. The thermody-namic analysis carried out by the authors allowed us to scientifically substantiate the experimentally observed in-tensification of the dissociation reaction of sulfates with an increase in temperature, a decrease in the partial pres-sure of oxygen in the furnace atmosphere during the processing of iron ore agglomerate. The data obtained in the study show that in oxidizing and slightly oxidizing conditions, sulfates decompose with increasing temperature if their contact with silicon and iron or aluminum oxides is ensured, and the formation of a melt accelerates mass exchange and promotes desulfurization. It is revealed that at the same time, liquid-phase sintering intensifies, in-hibiting the release of gases. In the conditions of the agglomeration process as a whole, the atmosphere is oxidiz-ing, although in some micro-volumes near the burning coke particles, the reducing potential of the gas phase is possible. Therefore, it makes sense to consider a uniform ratio between sulfate and sulfide sulfur in various gaseous environments.