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The article begins with analytical review of the works performed from 1940 up to nowadays, concerning the phenomenon of autohesion in the powders of inorganic compounds. The issues of terminology are concerned, the difference is discussed between the phenomena of autohesion, adhesion, and cohesion. Three groups of the components of autohesion forces are considered: van derWaals and electrical forces, cohesion and capillary forces and mechanical cohesion, as well as internal and external factors affecting these forces.
The second part of the article is devoted to the results of experiments performed to study the influence of the autohesion forces on the properties of friable inorganic powder materials. In particular, the rheological properties of powders were studied by static and dynamic methods on four kinds of electrocorundum powder with similar particle size and particle size distribution corresponding to the class of grinding powders F1200 according to FEPA standard. Special attention is paid to assessing the effect of humidity on technological properties of the powder, obtained by spray drying of ceramic slurry. This powder is widely used as a component of building mixes. The authors came to conclusion that detailed study is necessary of the autohesion effect on the parameters of friable systems for the rational choice of technological modes. The work can be useful for researchers and practitioners associated with the problems of processing, storage and transportation of powder materials. |
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