Communication 1 provides a brief overview of theoretical works on the creation of mathematical models of the sintering process, ranging from simplified balance models to the three-dimensional dynamic model. A modern three-dimensional mathematical model is adapted from industrial data on the agglomeration of a sinter mix in a bed 700 mm high with a bed of sinter at the sinter plant No. 5 of PJSC “MMK”. Changes in the device circuit diagram of sinter plan, the actual temperature of the mix, segregation of fuel along the height of the bed, the mode of intensive ignition of the mix in the ignition hearth with diffusion burners, the unevenness of the sintering process across the width of the pallets, additional heating of the bed after the hearth with air from a linear cooler, the actual degree of throttling of the vacuum chambers of the sinter machine, heat exchange in pallets are taken into account. The process of a combustion zone of solid fuel formation under the ignition hearth has been analyzed, and an increase in its height during the sintering process in a high bed has been established, that due to the segregation of mix and fuel along the height of the bed and the consumption of oxygen for the oxidation of FeO above this zone. The processes of limestone dissociation and melting of the mix zones formation and their development during the sintering process are considered