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Abstract

In high concentrated systems of several components the basic lows of zone refining and directional freezing are no longer valid. The dependance on the concentration of the segregation coefficient, the change in concentration and the unsufficient diffusion in the liquid phase have to be considered. A qualitativ valuation of the conditions for segregation can be drawn out of the phase diagram, though sedimentation can influence it and even reverse the direction of segregation.
In preparative and analytical chemistry and in the investigation of phase relations diretional freezing in systems of any concentration opens the way to interesting new possibilities.