The paper analyzes the properties of rocks with a shale structure, justifies the need to apply force in the direction of the lowest strength. The list of crushing equipment used in the process of obtaining cube-shaped crushed stone is given. It is established that the existing crushing equipment is not able to take into account the specific texture of the crushed materials and this does not allow obtaining cube-shaped crushed stone from shale materials. A description of the new design of the press-roll unit, which allows obtaining cuboid crushed stone from rocks with a shale structure, is given. The press-roll unit includes a device for directional feeding of shale materials to its working bodies, which create a force effect on the fed pieces of rock in the required direction. The design of the tooth of the working body is described, which allows to reduce significantly the replacement time of worn elements and reduce the bending loads acting on it. This leads to an increase in the reliability of the structure and reduces the metal consumption of repairs. A mathematical model of the directional movement of shale materials in a roll device is considered and an equation for calculating the required force is obtained. Graphical dependences of the influence of the roller installation angle and its horizontal and vertical displacement on the amount of deformation of the feed material layer are presented.
The article deals with the issues related to energy saving during grinding in a ball mill equipped with energy exchange devices, pre-milled in a press-roller grinder. The bulk solids movement analysis in a ball mill at different locations in the energy exchange devices drum is presented.
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.
The article presents the results of experimental studies on the grinding process of a clinker preliminarily ground in press roller mills in a ball mill equipped with energy exchange devices. The authors studied the influence of the coefficients of loading for grinding bodies of the first and second mill chambers, their lengths, angles of inclination, and the mutual location of energy exchange devices (the ellipse segment and the double-acting blade) on the output parameters of the grinding process (productivity, drive power consumption and specific energy consumption). It is clarified that the best results of the disaggregation and grinding process, judging by the minimum specific energy consumption in the grinding of clinker with an anisotropic texture after force deformation between the rolls of a press roller shredder, are achieved at a certain angle of ellipse segment inclination; the length of the first chamber and the coefficients of loading the chambers with grinding bodies.
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