Gamma-method study of the sedimenting concentrated suspensionsʹ structure

The density profiles (the density vs. height distribution) formation in various high-concentrated sedimenting suspensions have been studied by the annihilation gamma probe method. The sedimenting systems under study are found to be differed by the density profile features: (1) systems with lyophilic (as regards the dispersive liquid medium) surface character forming the sediment with uniformly increasing density down to the vessel bottom; (2) systems forming the low-density sediment layer near the vessel bottom; (3) systems with the distinct sedimentʹs macrolayers of different density; and (4) systems forming quasi-periodic macrolayers of various density along all the sedimentʹs height. The latter are characterized by a very high sedimentation stability. A possible mechanism of the macrolayers of different density formation was suggested. The layered sediments are a result of the periodical formation and destruction, when sedimenting under gravity, of a loose coagulative structure being formed over the lyophobic areas of the lyophilic–lyophobic surface mosaic particles.