Numerical and experimental analysis of an approach based on variable solute distribution coefficients during purification by zone refining

A combined theoretical and experimental approach was undertaken to quantitatively determine the influence of a variable solute distribution coefficient, k, on the impurity distribution in multi-pass purification by zone refining. A numerical model capable of predicting the solute redistribution at any stage of a multi-pass zone refining was used for providing simulations. Experimental work on zone refining was carried-out with Sb, Pb and Sn samples. Axial impurities profiles have been experimentally determined for a number of zone passes. These results have been compared with the theoretical predictions by adopting both variable and constant k values. It has been shown that the adoption of a variable solute distribution approach in the simulation of impurity profiles during different zone passes of zone refining are generally much closer to the experimental profiles than the usual adoption of a constant k.