<Original Papers>Zone-refining of Aluminium

The principal impurities, such as Fe, Cu and Si, in an Al rod refined by the zone-refining method were concentrated at the tail. The segregation of those elements was colorimetrically determined after passing 3～6 zones at the rates of 35 mm/hr and 70 mm/hr. The effective segregation coefficient K is given as follows : K_=0.21_8,K_=0.22_2 and K_=0.16_3 Except K_, they were in fairly agreement with the equilibrium segregation coefficients derived from the binary phase diagrams of Al-bearing alloy systems