Firing of magnetite iron ore pellets is shown to be accompanied by a set of physicochemical processes and oxidation of magnetite and carbonate decomposition occurring with exo- and endothermic effects are the most important among them. It is also shown that optimization of pellet heat treatment necessitates determination of the temperature intervals and duration of the processes along with the degree of their completion. This data array provides efficient distribution of the air-gas flows along the length of the burning conveyor machine taking into account the internal sources of heat Experimental gravimetric setup is used in studying kinetics of in-plant firing of Kachkanar pellets to elaborate and specify the optimum regimes of their heat treatment. The developed method can be used at various mining and processing plants of the country.