TABLE OF CONTENTS The refining of materials in modern technology is carried out by different methods. In a large majority of cases, the products of refining consist of particles of irregular geometrical shapes and different sizes. In most cases, the dimensions of some grains in the products of refining are hundreds and thousand times larger than the dimensions of other grains. The difference in the size of the grains of bulk materials of natural origin (for example, river or sea and) is slightly smaller than that of the products of refining but their composition is polydisperse. Strictly speaking, in nature, there are no monodisperse materials.
In most cases, the experimental determination of the grain size composition of the products of refining and classification is carried using the methods of sieve, microscopic and sedimentation analysis. Sieve analysis gives a satisfactory result only for fractions larger than 0.04 mm. For particles smaller than 0.04 mm, the grain size composition is determined by the sedimentation or centrifuging methods. These methods are based on different rates of settling of particles of different sizes. The size of the smallest grains (smaller than 5 ?m) is determined by laser scanning.
In classification in moving media, the separation of the material depends on the hydrodynamic properties of particles such as size, shape, surface condition, density, elasticity. The generally accepted analysis of the results of separation processes using sieves provides only a characteristic of the size of separation products and this is...
