Theoretical and experimental studies on the behaviour of liquid impurity in solid layer melt crystallizations

The concentration inside a crystalline layer was explored theoretically and experimentally for solid layer melt crystallizations. The distribution of the purity in the crystalline layer is modelled by a mass balance equation coupled with an energy balance equation. The mass balance equation is estab lished with the combination of the growth of the layer, the inclusion of th e impurity and the migration of the impurity. The concentration profiles we re obtained by considering both the migration of inclusions after the layer build-up and the entrapment of inclusion during the growth. The mathematic al model established is solved by a numerical method. The predictions are d iscussed with respect to the interfacial distribution coefficient, the migr ation effect for removing the inclusion, the concentration and temperature at the solid-liquid interface, crystalline layer thickness, the concentrati on of the layer, the crystal growth rate and the migration rate. The purity distribution obtained by the model was appropriately verified with that ob tained by the experiments.