The paper presents the study of the effectiveness of the grinding in an electromagnetic mill for limestone with the feed particle size up to 0.5 mm and 1 mm. The goal was to prepare material for specific particle size fractions of fine and coarse sorbents used for flue gas desulfurization. The work focused on optimizing the duration of the grinding and selecting grinding media properties to obtain the highest relative increase in the 50 μm and 50-100 μm particle size fraction in the grinding product. An important element for grinding control is the knowledge of the impact characteristics for main parameters and factors on the efficiency of the material comminution. The grinding results show its kinetics of grinding product yield. A model was also created that shows the relationship between grinding time and the process efficiency and can be used to optimize the process. The research allowed to determine the impact of changes in the parameters of the mill and the feed, which will allow to determine the controls for the system’s continuous operation. It is crucial to determine the efficiency of the mill. It depends on the degree of material fragmentation and the granularity of the feed subjected to the grinding. Both of these parameters are different for different raw materials. Determination of grinding kinetics models allowed to determine the dependence of function between the growth of the selected particle size fraction in the product and the residence time of material.