The paper provides an analysis of grinding systems used in the world practice, including the main technical solutions in the field of fine grinding of materials using a ball mill, and also presents indicators of their efficiency. It was found that the grinding systems of the partitioned grinding process with pre-grinding in a press-roll grinder showed the greatest efficiency from their use. However, today in various countries, free-standing units are used for deagglomeration of pressure-pressed semi-finished products, which require additional space for their placement and operation and maintenance costs. The authors describe the design of a press-roll unit with a device for breaking pressure-pressed materials, which allows reducing these costs, as it performs the following technological operations: volume-shear deformation of the material is carried out due to the conical profile of the main rolls; the compressed materials are disaggregated in the reverse direction of compression by means of additional rollers that have a reverse taper to the main rolls. A scientifically-based method for calculating the energy index of a new design of press roll unit is proposed, which allows for the energy calculation of these machines.