Abstract
Grinding processes, which are very common and occurring in almost any industry and agriculture, require large energy costs and are associated with irretrievable losses due to wear of working units of grinders. It is generally recognized that reduction in specific energy costs is possible when using mills in which grinding will be carried out mainly due to the impact loading of a material. The results of studies of a single impact grinding of materials with various physical and mechanical properties, depending on the impact velocity and design features of a grinder in an impact-centrifugal mill, are presented. Experimental dependences of impact-centrifugal grinding are presented. Graphic dependences of the median particle mass distribution of a ground material depending on the number of blades are obtained. The number of blades for a given rotor diameter (0.4 m) was 4, 6, 8, 12 pcs. The graph shows that when grinding chalk, the number of blades does not significantly affect the quality of grinding. When grinding sylvinite and in particular gypsum stone with an increase in the number of blades to 8, the grinding fineness improves, i.e., the median particle size decreases, however, with a further increase in the number of blades, the dispersed composition of the products remains almost constant. The analysis of known data on the theory of impact grinding is given, on the basis of which the principles of creating new energy-efficient machines for grinding materials, in particular to reduce energy costs, were formed.