Freezing, progressive component separation

Component Separation by Progressive Freezing When the distribution coefficient is less than I, the first solid which ciystaUizes contains less solute than the liquid from which it was formed. As the frac tion which is frozen increases, the concentration of the impurity in the remaining liquid is increased and hence the concentration of impurity in the sohd phase increases (for k < 1). The concentration gradient is reversed for k > 1. Consequently, in the absence of diffusion in the solid phase a concentration gradient is estabhshed in the frozen ingot. 

The results have implications for the structures in products. For example, for quiescently frozen products, the data produced here can be used to identify possible separation of solute components as freezing progresses. This implies that the frozen phase will change in composition and properties, dependent on the distance from and temperature of the cold sink. 

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