The development of certain indicators grindability materials techniques in a centrifugal impact mills

D. K. Zhirov

Institute of Mechanics, Ural Branch of the Russian Academy of Sciences, Izhevsk, Russia

Abstract: Every day over a hundred million tons of various materials is processed in the world. Mechanical grinding is the first step in process of obtaining high-strength structural nanomaterials. Greatest share of crushed raw materials is a bulk material, containing a few non-uniform components in the structure. There are minerals, non-metallic minerals, slag, grain, waste industry, agriculture, etc.
Multi-component materials are characterized by mechanical parameters: hardness, friability, bulk density, chemical composition. If we consider a multicomponent material as a feedstock for further processing, then, as a rule, it's solid particles with air in the voids. The distance between particles in a material during its processing varies continuously. As a result, the bulk density of particulate material is not constant value. Static or dynamic compressive load to the material allows to significantly reduce the distance between solid particles. The dynamic load, unlike static allows to compress material more.
Grinding materials can be produced in various ways, the most common: crush breakage, impact, abrasion, cutting or a combination of these methods. The analysis of the static and dynamic loading research of different materials shows that the most effective milling method for majority of heterogeneous multi-component materials is a free kick.
The analysis of existing methods for determining the grindability index from the point of efficiency using to determine the impact energy and impact quantity on the destruction process in the multistage centrifugal impact mills is produced. The analysis showed many shortcomings in existing methods applied to modeling the milling process in multistage centrifugal mills. The particle destruction technique a series of punches, provided for a total applied energy shock cycle less the energy required to break the particles with one shock has been developed. This technique allows the most authentically simulate the particles destruction process the in the multi-stage centrifugal impact mills, and allows you to define the required particle acceleration speed of the material, the optimal mode of destruction and the expected particle size distribution for the given parameters of work.
Using developed techniques in conjunction with the developed particles motion model to disperse blades can be used in the design of centrifugal impact crushers and to select optimal modes of existing mills at crushing various solid-bulk materials.

Keywords: particle, centrifugal shock mill, grindability index, escape velocity, shock, blade.

UDC: 622.73:519.6